Theory of the Earth, Volume 1 (of 4)
by
James Hutton
Part 3 out of 6
Substances.
A theory which is founded on a new principle, a theory which has to make
its way in the public mind by overturning the opinions commonly received
by philosophising men, and one which has nothing to recommend it but the
truth of its principles, and the view of wisdom or design to which it
leads, neither of which may perhaps be perceived by the generality of
people, such a theory, I say, must meet with the strongest opposition
from the prejudices of the learned, and from the superstition of those
who judge not for themselves in forming their notions, but look up to
men of science for authority. Such is the case with some part of the
Theory of the Earth, which I have given, and which will probably give
offence to naturalists who have espoused an opposite opinion. In order,
then, to obtain the approbation of the public, it may not be enough to
give a theory that should be true, or altogether unexceptionable it may
be necessary to defend every point that shall be thought exceptionable
by other theorists, and to show the fallacy of every learned objection
that may be made against it. It is thus, in general, that truth and
error are forced to struggle together, in the progress of science; and
it is only in proportion as science removes erroneous conceptions, which
are necessarily in the constitution of human knowledge, that truth will
find itself established in natural philosophy.
Mr Kirwan has written a dissertation, entitled, _Examination of the
Supposed Igneous Origin of Stony Substances_, which was read in the
Royal Irish Academy. The object of that dissertation is to state certain
objections, which have occurred to him, against the Theory of the Earth
published in the Transactions of the Edinburgh Royal Society; and he has
attacked that theory in all the points where it appears to him to be
vulnerable. It is to these objections that I am now to give an answer.
The authority given to this dissertation, by the Royal Irish Academy,
as well as the reputation of the author, make it necessary for me
to endeavour to put in their true light the facts alleged in that
performance, and to analyse the arguments employed, in order to judge of
the reasoning by which the theory of mineral fusion is refuted in this
Examination.
A theory founded on truth, and formed according to the proper rules of
science, can ever suffer from a strict examination, by which it would
be but the more and more confirmed. But, where causes are to be traced
through a chain of various complicated effects, an examination not
properly conducted upon accurate analytical principles, instead of
giving light upon a subject in which there had been obscurity and doubt,
may only serve to perplex the understanding, and bring confusion into a
subject which was before sufficiently distinct. To redress that evil,
then, must require more labour and some address; and this is an
inconveniency that may be looked for, more or less, in every
controversial discussion.
I do not mean to enter any farther into the defence of my theory in
this chapter, than what is necessary to answer a man of science and
respectability, who has stated his objections. The observations which
he has made appear to me to be founded on nothing more than common
prejudice, and misconceived notions of the subject. I am therefore
to point out that erroneous train of reasoning, into which a hasty
superficial view of things, perhaps, has led the patron of an opposite
opinion to see my theory in an unfavourable light. This, however, is not
all; for, that train of inconsequential reasoning is so congenial with
the crude and inconsiderate notion generally entertained, of solid
mineral bodies having been formed by the infiltration of water into
the earth, that no opportunity should be lost of exposing an erroneous
manner of reasoning, which is employed in supporting a hypothesis
founded upon certain operations of the surface of this earth that cannot
be properly applied to the formation of mineral bodies. This object,
therefore, so far as it may come in the way, will be attended to in
this discussion, although I shall have another opportunity of farther
enlarging upon that subject.
Our author begins by examining a geological operation, the very opposite
to that of mineral consolidation, and which would seem to have little
connection with the subject of this dissertation. In my theory, I
advanced two propositions with regard to the economy of this world:
First, That the solid masses of this earth, when exposed to the
atmosphere, decay, and are resolved into loose materials, of which the
vegetable soil upon the surface is in part composed; and, secondly, That
these loose materials are washed away by the currents of water, and
thus carried at last into the sea. Our author says "Here are two
suppositions, neither of which is grounded on facts;" and yet he has
but the moment before made the following confession: "That the soil,
however, receives an increase from some species of stones that moulder
by exposition to the air cannot be denied, but there is no proof that
all soil has arisen from decomposition."--Surely _all soil_, that
is made from the _hard and compact_ body of the land, which is my
proposition, must have arisen from _decomposition_; and I have no where
said, that _all_ the soil of this earth is made from the decomposition
or detritus of those stony substances; for, masses of looser sand and
softer substances contribute still more to the formation of vegetable
soils.
With regard to the other proposition, our author says, "Soil is not
constantly carried away by the water, even from mountains."--I have not
said that it is _constantly_ washed away; for, while it is soil in which
plants grow, it is not travelling to the sea, although it be on the road,
and must there arrive in time. I have said, that it is _necessarily_
washed away, that is, occasionally. M. de Luc's authority is then
referred to, as refuting this operation of water and time upon the soil.
Now, I cannot help here observing, that our author seems to have as
much misapprehended M. de Luc's argument as he has done mine. That
philosopher, in his letters to the Queen, has described most accurately
the decay of the rocks and solid mountains of the Alps and Jura, and the
travelling of their materials by water, although he does not carry them
to the sea. It is true, indeed, that this author, who supposes the
present earth on which we dwell very young, is anxious to make an earth,
_in time_, that shall not decay nor be washed away at all; but that time
is not come yet; therefore the authority, here given against my
theory, is the speculative supposition, or mere opinion, of a natural
philosopher, with regard to an event which may never come to pass, and
which I shall have occasion to consider fully in another place.
Our author had just now said, that I have advanced two suppositions,
_neither of which is grounded on facts_: Now, with regard to the one, he
has acknowledged, that the mouldering of stones takes place, which is
the fact on which that proposition is grounded; and with regard to the
other, the only authority given against it is founded expressly upon
the moving of soil by means of the rain water, in order to make sloping
plains of mountains. Here, therefore, I have grounded my propositions
upon facts; and our author has founded his objections, first, upon a
difficulty which he has himself removed; and, secondly, upon nothing but
a visionary opinion, with regard to an earth which is not yet made, and
which, when once made, is never more to change.
After making some unimportant observations,--of all water not flowing
into the sea,--and of the travelled materials being also deposited upon
the plains, etc. our author thus proceeds: "Hence the conclusion of our
author relative to the imperfect constitution of the globe falls to the
ground; and the pains he takes to learn, _by what means a decayed world
may be renovated_, are superfluous."--The object of my theory is
to show, that this decaying nature of the solid earth is the very
_perfection_ of its constitution, as a living world; therefore, it
was most proper that I should _take pains to learn_ by what means the
decayed parts might be renovated. It is true, indeed, that this will be
superfluous, when once that constitution of the earth, which M. de Luc
thinks is preparing, shall be finished; but, in the mean time, while
rivers carry the materials of our land, and while the sea impairs the
coast, I may be allowed to suppose that this is the actual constitution
of the earth.
I cannot help here animadverting upon what seems to be our author's
plan, in making these objections, which have nothing to do with his
examination. He accuses me of giving this world a false or imperfect
constitution, (in which the solid land is considered as resolvable, and
the materials of that land as being washed away into the sea,) for no
other reason, that I can see, but because this may imply the formation
of a future earth, which he is not disposed to allow; and, he is now to
deny the stratified construction of this present earth to have been made
by the deposits of materials at the bottom of the sea, because that
would prove the existence of a former earth, which is repugnant to his
notion of the origin of things, and is contrary, as he says, to reason,
and the tenor of the Mosaic history. Let me observe, in passing, that M.
de Luc, of whose opinions our author expresses much approbation, thinks
that he proves, from the express words and tenor of the Mosaic history,
that the present earth was at the bottom of the sea not many years ago,
and that the former earth had then disappeared.
But, what does our author propose to himself, in refusing to admit my
view of the operations which are daily transacting upon the surface of
this earth, where there is nothing dark or in the least mysterious, as
there may be in the mineral regions? Does he mean to say, that it is not
the purpose of this world to provide soil for plants to grow in? Does
he suppose that this soil is not moveable with the running water of the
surface? and, Does he think that it is not necessary to replace that
soil which is removed? This is all that I required in that constitution
of the world which he has thus attacked; and I wish that he or any
person would point out, in what respect I had demanded any thing
unreasonable, or any thing that is not actually to be observed every
day.
Thus I have endeavoured to show, that our author has attacked my theory
in a part where I believe it must be thought invulnerable; but this is
only, I presume, in order that he may make an attack with more advantage
upon another part, viz. the composition of strata from the materials of
an earth thus worn out in the service of vegetation,--materials which
are necessarily removed in order to make way for that change of things
in which consists the active and living system of this world. If he
succeed in this attempt to refute my theory of the original formation
of strata, he would then doubtless find it more easy to persuade
philosophers that the means which I employ in bringing those materials
again to light, when transformed into such solid masses as the system of
this earth requires, are extravagant, unnatural, and unnecessary. Let us
then see how he sets about this undertaking.
With regard to the composition of the earth, it is quoted from my
theory, that _the solid parts of the globe are in general composed
of sand, gravel, argillaceous and calcareous strata, or of various
compositions of these with other substances_; our author then adds,
"This certainly cannot be affirmed as a fact, but rather the contrary;
it holds only true of the surface, the basis of the greater part of
Scotland is evidently a granitic rock, to say nothing of the continents,
both of the Old and New World, according to the testimony of all
mineralogists." This proposition, with regard to the general composition
of the earth, I have certainly not assumed, I have maintained it as a
fact, after the most scrupulous examination of all that, with the most
diligent search, I have been able to see, and of all that authors
have wrote intelligibly upon the subject. If, therefore, I have so
misrepresented this great geological fact on which my theory is
absolutely founded, I must have erred with open eyes; and my theory
of the earth, like others which have gone before it, will, upon close
examination, appear to be unfounded, as the dissertation now before us
is endeavouring to represent it.
Our author here, I think, alleges that the contrary to this, my
fundamental proposition, is the truth; and he has given us Scotland as
an example in which his assertion (founded upon the testimony of all
mineralogists), is illustrated. Now my geological proposition should
certainly be applicable to Scotland, which is the country that I ought
to be best acquainted with; consequently, if what our author here
asserts be true, I would have deserved that blame which he is willing to
throw on me. Let me then beg the readers attention for a moment, that I
may justify myself from that charge, and place in its proper light this
authority, upon so material a point in geology.
I had examined Scotland from the one end to the other before I saw one
stone of granite in its native place, I have moreover examined almost
all England and Wales, (excepting Devonshire and Cornwall) without
seeing more of granite than one spot, not many hundred yards of extent;
this is at Chap; and I know, from information, that there is another
small spot in the middle of England where it is just seen. But, let me
be more particular with regard to Scotland, the example given in proof.
I had travelled every road from the borders of Northumberland and
Westmoreland to Edinburgh; from Edinburgh, I had travelled to
Port-Patrick, and from that along the coast of Galloway and Airshire
to Inverary in Argyleshire, and I had examined every spot between the
Grampians and the Tweedale mountains from sea to sea, without seeing
granite in its place. I had also travelled from Edinburgh by Grief,
Rannock, Dalwhiny, Fort Augustus, Inverness, through east Ross and
Caithness, to the Pentland-Frith or Orkney islands, without seeing one
block of granite in its place. It is true, I met with it on my return
by the east coast, when I just saw it, and no more, at Peterhead and
Aberdeen; but that was all the granite I had ever seen when I wrote
my Theory of the Earth. I have, since that time, seen it in different
places; because I went on purpose to examine it, as I shall have
occasion to describe in the course of this work.
I may now with some confidence affirm, from my own observation, and from
good information with regard to those places where I have not been,
except the northwest corner, I may affirm, I say, that instead of the
basis of the greatest part of Scotland being a granitic rock, which our
author has maintained as an evident thing, there is very little of it
that is so; not perhaps one five hundred part. So far also as I am to
judge from my knowledge of the mineral construction of England and
Wales, which I have examined with the greatest care, and from the
mineral chart which my friend Mr Watt made for me from his knowledge of
Cornwall, I would say that there is scarcely one five hundred part
of Britain that has granite for its basis. All the rest, except the
porphyry and basaltes, consists of stratified bodies, which are composed
more or less of the materials which I mentioned, generally, in the above
quotation, and which our author would dispute.
But do not let me take the advantage of this error of our author with
regard to the mineralogy of Scotland, and thus draw what may be thought
an undue conclusion in favour of my general theory; let us go over and
examine the continent of Europe, and see if it is any otherwise there
than in Britain. From the granite of the Ural mountains, to that which
we find in the Pyrenees, there is no reason, so far as I have been able
to learn, to conclude that things are formed either upon any other
principle, or upon a different scale. But, instead of one five hundred
part, let us suppose there to be one fiftieth part of the earth in
general resting upon granite, I could not have expressed myself
otherwise than I have done; for, when I maintained that the earth in
general consisted of stratified bodies, I said that this was only _nine
tenths, or perhaps ninety-nine hundredths_ of the whole, and I mentioned
that there were other masses of a different origin, which should be
considered separately. Our author, on the contrary, asserts that the Old
and New Worlds, as well as Scotland, are placed upon granite as a basis,
which he says is according to the testimony of all mineralogists.
I shall have occasion to examine this opinion of mineralogists, in
comparing it with those masses of granite which appear to us; and I hope
fully to refute the geological, as well as mineralogical notions with
regard to that body. In the mean time, let me make the following
reflection, which here naturally occurs.
My Theory of the Earth is here examined,--not with the system of
nature, or actual state of things, to which it certainly should have
corresponded,--but with the systematic views of a person, who has formed
his notions of geology from the vague opinion of others, and not from
what he has seen. Had the question been, How far my theory agreed with
other theories, our author might very properly have informed his readers
that it was diametrically opposite to the opinions of mineralogists;
but, this was no reason for concluding it to be erroneous; on the
contrary, it is rather a presumption that I may have corrected the error
of mineralogists who have gone before me, in like manner as it is most
reasonable to presume that our author may have corrected mine. Let us
then proceed to examine how far this shall appear to be the case.
Our author has stated very fairly from the Theory, viz. _That all the
strata of the earth, not only those consisting of calcareous masses, but
others superincumbent on these, have had their origin at the bottom
of the sea, by the collection of sand, gravel, shells, coralline, and
crustaceous bodies, and of earths and clays variously mixed, separated,
and accumulated._ He then adds, "Various geological observations
contradict this conclusion. There are many stratified mountains of
argillaceous slate, gneiss, serpentine, jasper, and even marble, in
which either sand, gravel, shells, coralline, or crustaceous bodies are
never, or scarce ever found."
Here our author seems to have deceived himself, by taking a very partial
view of things which should be fully examined, and well understood,
before general conclusions are to be drawn from those appearances; for,
although those particular objects may not be visible in the strata which
he has enumerated, or many others, they are found in those strata which
are either immediately connected and alternated with them, or with
similar strata; something to that purpose I think I have said; and, if
I had not, it certainly requires no deep penetration to have seen this
clear solution of that appearance of those objects not being found in
every particular stratum. He says that those marks of known materials
are never or scarce ever found;--by _scarce ever_ he surely means that
they are sometimes found; but if they shall only _once_ be found, his
argument is lost. I have not drawn my geological conclusion from every
particle in strata being distinguishable, but from there being certain
distinguishable particles in strata, and from our knowing what had been
the former state and circumstances of those distinguished parts.
If every stone or part of a stratum, in which those known objects are
not immediately visible, must be considered as so _many geological
observations that contradict my theory_, (of strata being formed from
the materials of a former earth), then, surely every stone and every
stratum which visibly contains any of those materials, must prove my
theory. But if every stratum, where these are found in any part of it,
is to be concluded as having had its origin at the bottom of the sea;
and, if every concomitant stratum, though not having those objects
visible or sufficiently distinct, must be considered as having had the
same or a similar origin, that pretended contradiction of my theory
comes to no more than this, that every individual stone does not bear
in it the same or equal evidence of that general proposition which
necessarily results from the attentive consideration of the whole,
including every part.
But to see how necessary it is to judge in this manner, not partially,
but upon the whole, we may observe, that there are two ways by which the
visible materials or distinguishable bodies of a former earth, not only
_may_ be rendered invisible in the composition of our present earth,
but _must_ be so upon many occasions. These are, _first_, by mechanical
comminution, which necessarily happens, more or less, in that operation
by which bodies are moved against one another, and thus transported from
the land to the bottom of the deepest seas; _secondly_, by chemical
operations, (whatever these may be, whether the action of water or of
fire, or both), which are also necessarily employed for consolidating
those loose materials, that are to form the rocks and stones of
this earth, and by means of which those materials are to have their
distinguishable shapes affected in all degrees and obliterated.
Therefore, to demand the visible appearance of those materials in every
stratum of the earth, or in every part of a stratum, is no other than to
misunderstand the subject altogether. The geological observations,
which have been thus alleged as contradicting my theory, are stratified
bodies, containing proofs of the general origin which I attribute to the
earth, but proofs which may not always be seen with equal facility as
those which even convince the vulgar.
Our author has surely perplexed himself with what writers of late have
said concerning primitive mountains as they are called, a subject of
deeper search, than is commonly imagined, as I hope to show in the
course of this work. It is an interesting subject of investigation,
as giving us the actual view of those operations of nature which, in
forming my Theory of the Earth, more general principles had led me to
conclude _might be_. But, it is a subject which, I am afraid, will lead
me to give farther offence to our author, however innocent I may be in
giving nothing but what I have from nature.
The reason for saying so is this; I am blamed for having endeavoured
to trace back the operations of this world to a remote period, by the
examination of that which actually appears, contrary, as is alleged,
"to reason, and the tenor of the Mosaic history, thus leading to an
abyss, from which human reason recoils, etc." In a word, (says our
author), "to make use of his own expression, _We find no vestige of
a beginning._ Then this system of successive worlds must have been
eternal." Such is the logic by which, I suppose, I am to be accused of
atheism. Our author might have added, that I have also said--_we see
no prospect of an end_; but what has all this to do with the idea of
eternity? Are we, with our ideas of _time_, (or mere succession), to
measure that of eternity, which never succeeded any thing, and which
will never be succeeded? Are we thus to measure eternity, that boundless
thought, with those physical notions of ours which necessarily limit
both space and time? and, because we see not the beginning of created
things, Are we to conclude that those things which we see have always
been, or been without a cause? Our author would thus, inadvertently
indeed, lead himself into that gulf of irreligion and absurdity into
which, he alleges, I have _boldly plunged_.
In examining this present earth, we find that it must have had its
origin at the bottom of the sea, although our author seems willing to
deny that proposition. Farther, in examining the internal construction
of this stratified and sea-born mass, we find that it had been composed
of the moved materials of a former earth; and, from the most accurate
and extensive examination of those materials, which in many places are
indeed much disguised, we are led necessarily to conclude, that there
had been a world existing, and containing an animal, a vegetable, and a
mineral system. But, in thus tracing back the natural operations which
have succeeded each other, and mark to us the course of time past, we
come to a period in which we cannot see any farther. This, however,
is not the beginning of those operations which proceed in time and
according to the wise economy of this world; nor is it the establishing
of that, which, in the course of time, had no beginning; it is only the
limit of our retrospective view of those operations which have come to
pass in time, and have been conducted by supreme intelligence.
My principal anxiety was to show how the constitution of this world
had been wisely contrived; and this I endeavoured to do, not from
supposition or conjecture, but from its answering so effectually the end
of its intention, viz. the preserving of animal life, which we cannot
doubt of being its purpose. Here then is a world that is not eternal,
but which has been the effect of wisdom or design.
With regard again to the prospective view of the creation, How are we to
see the end of that wise system of things which so properly fulfils the
benevolent intention of its maker,--in giving sustenance to the animal
part, and information to intellectual beings, who, in these works of
nature, read what much concerns their peace of mind,--their intellectual
happiness? What then does our author mean, in condemning that
comprehensive view which I have endeavoured to take of nature? Would he
deny that there is to be perceived wisdom in the system of this world,
or that a philosopher, who looks into the operations of nature, may not
plainly read the power and wisdom of the Creator, without recoiling, as
he says, from the abyss? The abyss, from which a man of science should
recoil, is that of ignorance and error.
I have thus shown, that, from not perceiving the wise disposition of
things upon the surface of this earth for the preservation of vegetable
bodies, our author has been led to deny the necessary waste of the
present earth, and the consequent preparation of materials for the
construction of another; I have also shown, that he denies the origin
which I had attributed to the stratified parts of this earth, as having
been the collection of moving materials from a former earth; and now
I am come to consider the professed purpose of this paper, viz. the
examination of solid stony substances which we find in those strata
of our earth, as well as in more irregular masses. Here, no doubt, my
theory would have been attacked with greater success, had our author
succeeded in pointing out its error with regard to the original
composition of those indurated bodies, to which I ascribe fusion as the
cause of their solidity. For, if we should, according to our author's
proposition, consider those consolidated bodies as having been
originally formed in that solid state, here the door might be shut
against any farther investigation;--But to what purpose?--Surely not to
refute my theory, but to explode every physical inquiry farther on the
subject, and thus to lead us back into the science of darkness and of
scepticism. But let us proceed to see our author's sentiments on this
subject.
As I had proved from matter of fact, or the actual appearances of
nature, that all the strata of the earth had been formed at the bottom
of the sea, by the subsidence of those materials which either come from
the decaying land, or are formed in the sea itself, it was necessary
that I should consider in what manner those spongy or porous bodies of
loose materials, gathered together at the bottom of the sea, could have
acquired that consolidated state in which we find them, now that they
are brought up to our examination. Upon this occasion, our author says,
"The particles which now form the solid parts of the globe need not be
supposed to have originally been either spongy or porous, the interior
parts at the depth of a few miles might have been originally, as at
present, a solid mass." If, indeed, we shall make that supposition, we
may then save ourselves the trouble of considering either how the strata
of the earth have been formed or consolidated; for, they might have been
so originally. But, how can a naturalist who had ever seen a piece of
Derbyshire marble, or any other shell limestone, make that supposition?
Here are, to the satisfaction of every body of common understanding who
looks at them, bodies which are perfectly consolidated, bodies which
have evidently been formed at the bottom of the sea, and therefore which
were not originally a solid mass. Mr Bertrand, it is true, wrote a book
to prove that those appearances were nothing but a _lusus naturae_; and,
I suppose he meant, with our author, that those strata had been also
originally, as at present, a solid mass.
With regard to the consolidation of strata, that cardinal point for
discussion, our author gives the following answer: "Abstracting from his
own gratuitous hypothesis, it is very easy to satisfy our author on this
head; the concreting and consolidating power in most cases arises from
the mutual attraction of the component particles of stones to each
other." This is an answer with regard to the _concreting power_, a
subject about which we certainly are not here inquiring. Our author,
indeed, has mentioned a _consolidating power_; but that is an improper
expression; we are here inquiring, How the interstices, between the
collected materials of strata, deposited at the bottom of the sea, have
been filled with a hard substance, instead of the fluid water which had
originally occupied those spaces. Our author then continues; "If these
particles leave any interstices, these are filled with water, which no
ways obstructs their solidity when the points of contact are numerous;
hence the decrepitation of many species of stones when heated."
If I understand our author's argument, the particles of stone are, by
their mutual attractions, to leave those hard and solid bodies which
compose the strata, that is to say, those hard bodies are to dissolve
themselves; but, To what purpose? This must be to fill up the
interstices, which we must suppose occupied by the water. In that case,
we should find the original interstices filled with the substances which
had composed the strata, and we should find the water translated into
the places of those bodies; here would be properly a transmutation, but
no consolidation of the strata, such as we are here to look for, and
such as we actually find among those strata. It may be very easy for
our author to form those explanations of natural phenomena; it costs
no tedious observation of facts, which are to be gathered with labour,
patience, and attention; he has but to look into his own fancy, as
philosophers did in former times, when they saw the abhorrence of a
vacuum and explained the pump. It is thus that we are here told the
consolidation of strata _arises from the mutual attraction of the
component particles of stones to each other_; the power, by which the
particles of solid stony bodies retain their places in relation to each
other, and resist separation from the mass, may, no doubt, be properly
enough termed their mutual attractions; but we are not here inquiring
after that power; we are to investigate the power by which the particles
of hard and stony bodies had been separated, contrary to their mutual
attractions, in order to form new concretions, by being again brought
within the spheres of action in which their mutual attractions might
take place, and make them one solid body. Now, to say that this is by
their mutual attraction, is either to misunderstand the proper question,
or to give a most preposterous answer.
It is not every one who is fit to reason with regard to abstract general
propositions; I will now, therefore, state a particular case, in
illustration of that proposition which has been here so improperly
answered. The strata of Derbyshire marbles were originally immense
collections at the bottom of the sea, of calcareous bodies consisting
almost wholly of various fragments of the _entrochi_; and they were then
covered with an indefinite number of other strata under which these
_entrochi_ must have been buried. In this original state of those
strata, I suppose the interstices between the fragments of the coralline
bodies to have been left full of sea-water; at present we find those
interstices completely filled with a most perfectly solid body of
marble; and the question is, whether that consolidating operation
has been the work of water and solution, by our naturalist's termed
infiltration; or if it has been performed, as I have maintained, by the
softening power or heat, or introduction of matter in the fluid state
of fusion. Our author does not propose any other method for the
consolidation of those loose and incoherent bodies, but he speaks of the
_mutual attraction of the component particles of stone to each other_;
Will that fill the interstices between the coralline bodies with solid
marble, as well as consolidate the coralline bodies themselves? or, if
it should, How are those interstices to be thus filled with a substance
perfectly different from the deposited bodies, which is also frequently
the case? But, how reason with a person who, with this consolidation of
strata, confounds the well known operation by which the mortar, made
with caustic lime and sand, becomes a hard body! One would imagine
that he were writing to people of the last age, and not to chemical
philosophers who know so well how that mortar is concreted.
To my argument, That these porous strata are found _consolidated with
every different species of mineral substance_, our author makes the
following observation: "Here the difficulties to the supposition of an
aqueous solution are placed in the strongest light; yet it must be owned
that they partly arise from the author's own gratuitous supposition,
that strata existed at the bottom of the sea previous to their
consolidation;"--gratuitous supposition!--so far from being a
supposition of any kind, it is a self evident proposition; the terms
necessarily imply the conclusion. I beg the readers attention for a
moment to this part of our author's animadversion, before proceeding to
consider the whole; for, this is a point so essential in my theory,
that if it be a gratuitous supposition, as is here asserted, it would
certainly be in vain to attempt to build upon it the system of a world.
That strata may exist, whether at the bottom of the sea, or any other
where, without being consolidated, will hardly be disputed; for, they
are actually found consolidated in every different degree. But, when
strata are found consolidated, at what time is it that we are to suppose
this event to have taken place, or this accident to have happened to
them?--Strata are formed at the bottom of water, by the subsidence or
successive deposits of certain materials; it could not therefore
be during their formation that such strata had been consolidated;
consequently, we must necessarily _conclude_, without any degree of
_supposition_, that _strata had existed at the bottom of the sea
previous to their consolidation_, unless our author can show how they
may have been consolidated previous to their existing.
This then is what our author has termed a gratuitous supposition of
mine, and which, he adds, "is a circumstance which will not be allowed
by the patrons of the aqueous origin of stony substances, as we have
already seen."--I am perfectly at a loss to guess at what is here
alluded to _by having been already seen_, unless it be that which I have
already quoted, concerning things which have been never seen, that
is, _those interior parts of the earth which were originally a solid
mass_.--I have hardly patience to answer such reasoning;--a reasoning
which is not founded upon any principle, which holds up nothing
but chimera to our view, and which ends in nothing that is
intelligible;--but, others, perhaps, may see this dissertation of our
author's in a different light; therefore, it is my duty to analyse the
argument, however insignificant it may seem to me.
I have minutely examined all the stratified bodies which I have been
able, during a lifetime, to procure, both in this country of Britain,
and from all the quarters of the globe; and the result of my inquiry has
been to conclude, that there is nothing among them in an original state,
as the reader will see in the preceding chapter. With regard again to
the masses which are not stratified, I have also given proof that they
are not in their original state, such as granite, porphyry, serpentine,
and basaltes; and I shall give farther satisfaction, I hope, upon that
head, in the course of this work. I have therefore concluded, That there
is nothing to be found in an original state, so far as we see, in the
construction of this earth. But, our author answers, That the interior
parts _might have been in an original state of solidity_.--So might
they have been upon the surface of the earth, or on the summits of our
mountains; but, we are not inquiring What they _might have been_, but
What they truly _are_. It is from this actual state in which the solid
parts of the earth are found, that I have endeavoured to trace back the
different states in which they must have been; and, by generalising
facts, I have formed a theory of the earth. If this be a wrong principle
or manner of proceeding in a physical investigation, or if, proceeding
upon that principle, I have made the induction by reasoning improperly
on any occasion, let this be corrected by philosophers, who may reason
more accurately upon the subject. But to oppose a physical investigation
with this proposition, _that things might have been otherwise_, is to
proceed upon a very different principle,--a principle which, instead of
tending to bring light out of darkness, is only calculated to extinguish
that light which we may have acquired.
I shall afterwards have occasion to examine how far the philosophers,
who attribute to aqueous solution the origin of stony substances, have
proceeded in the same inductive manner of reasoning from effect to
cause, as they ought to do in physical subjects, and not by feigning
causes, or following a false analogy; in the mean time, I am to answer
the objections which have been made to the theory of the earth.
In opposition to the theory of consolidating bodies by fusion, our
author has taken great pains to show, that I cannot provide materials
for such a fire as would be necessary, nor find the means to make it
burn had I those materials. Had our author read attentively my theory he
would have observed, that I give myself little or no trouble about that
fire, or take no charge with regard to the procuring of that power, as I
have not founded my theory on the _supposition_ of subterraneous
fire, however that fire properly follows as a conclusion from those
appearances on which the theory is founded. My theory is founded upon
the general appearances of mineral bodies, and upon this, that mineral
bodies must necessarily have been in a state of fusion. I do not pretend
to prove, demonstratively, that they had been even hot, however that
conclusion also naturally follows from their having been in fusion. It
is sufficient for me to demonstrate, That those bodies must have been,
more or less, in a state of softness and fluidity, without any species
of solution. I do not say that this fluidity had been without heat;
but, if that had been the case, it would have answered equally well the
purpose of my theory, so far as this went to explain the consolidation
of strata or mineral bodies, which, I still repeat, must have been
by simple fluidity, and not by any species of solution, or any other
solvent than that universal one which permeates all bodies, and which
makes them fluid.
Our author has justly remarked the difficulty of fire burning below the
earth and sea. It is not my purpose here to endeavour to remove those
difficulties, which perhaps only exist in those suppositions which are
made on this occasion; my purpose is to show, that he had no immediate
concern with that question, in discussing the subject of the
consolidation which we actually find in the strata of the earth, unless
my theory, with regard to the igneous origin of stony substances, had
proceeded upon the supposition of a subterraneous fire. It is surely one
thing to employ fire and heat to melt mineral bodies, in supposing this
to be the cause of their consolidation, and another thing to acknowledge
fire or heat as having been exerted upon mineral bodies, when it is
clearly proved, from actual appearances, that those bodies had been in
a melted state, or that of simple fluidity. Here are distinctions which
would be thrown away upon the vulgar; but, to a man of science, who
analyses arguments, and reasons strictly from effect to cause, this is,
I believe, the proper way of coming at the truth. If the patrons of
the aqueous origin of stony substances can give us any manner of
scientifical, _i.e._ intelligible investigation of that process, it
shall be attended to with the most rigid impartiality, even by a patron
of the igneous origin of those substances, as he wishes above all things
to distinguish, in the mineral operations, those which, on the one hand,
had been the effect of water, from those which, on the other hand, had
been the immediate effect of fire or fusion;--this has been my greatest
study. But, while mineralists or geologists give us only mere opinions,
What is science profited by such inconsequential observations, as are
founded upon nothing but our vulgar notions? Is the figure of the
earth, _e.g._ to be doubted, because, according to the common notion of
mankind, the existence of an antipod is certainly to be denied?
I am not avoiding to meet that question with regard to the providing
of materials for such a mineral fire as may be required; no question I
desire more to be asked to resolve; but it must not be in the manner
that our author has put that question. He has included this supposed
difficulty among a string of other arguments by which he would refute my
theory with regard to the igneous origin of stony substances, as if I
had made that fire a necessary condition or a principle in forming my
theory of consolidation. Now, it is precisely the reverse; and this is
what I beg that mineral philosophers will particularly attend to, and
not give themselves so much unnecessary trouble, and me so disagreeable
a talk. I have proved that those stony substances have been in the fluid
state of fusion; and from this, I have inferred the former existence of
an internal heat, a subterraneous fire, or a certain cause of fusion by
whatever name it shall be called, and by whatever means it shall have
been procured. The nature of that operation by which strata had been
consolidated, like that by which they had been composed, must, according
to my philosophy, be decided by ocular demonstration; from examining the
internal evidence which is to be found in those bodies as we see them in
the earth; because the consolidating operation is not performed in our
sight, no more than their stratification which our author has also
denied to have been made, as I have said, by the deposits of materials
at the bottom of the sea. Now, with regard to the means of procuring
subterraneous fire, if the consolidating operation shall be thus decided
to have been that of fusion, as I think I have fully shown, and for
which I have as many witnesses, perhaps as there are mineral bodies,
then our author's question, (how I am to procure a fire) in the way that
he has put it, as an argument against the fusion, would be at least
useless; for, though I should here confess my ignorance with regard to
the means of procuring fire, the evidence of the melting operation, or
former fluidity of those mineral bodies, would not be thereby in the
least diminished. If again no such evidence for the fusion of those
bodies shall appear, and it be concluded that they had been consolidated
by the action of water alone, as our author seems inclined to maintain,
he would have no occasion to start difficulties about the procuring of
fire, in order to refute a theory which then would fall of itself as
having no foundation.
But in order to see this author's notion of the theory which he is here
examining, it may be proper to give a specimen of his reasoning upon
this subject of heat. He says, "That my supposition of heat necessary
for consolidating strata is _gratuitous_, not only because it is
unnecessary, as we have already shown, but also because it is
inconsistent with our author's own theory." Let us now consider those
two propositions. _First_, it is unnecessary, _as we have already
shown_;--I have already taken particular notice of what we have been
shown on this occasion, viz. That the earth at a certain depth _may
have been originally in a solid state_; and, that, where it is to be
consolidated, this is done by the _mutual attraction of the stony
particles_. Here is all that we have been shown to make subterraneous
heat, for the consolidation of strata, unnecessary; and now I humbly
submit, if this is sufficient evidence, that mineral heat is a
gratuitous supposition.
Secondly, "_it is inconsistent with our author's own theory._" Here
I would beg the readers attention to the reasoning employed on
this occasion. He says, "according to him these strata, which were
consolidated by heat, were composed of materials gradually worn from a
preceding continent, casually and successively deposited in the sea;
Where then will he find, and how will he suppose, to have been formed
those enormous masses of sulphur, coal, or bitumen, necessary to produce
that immense heat necessary for the fusion of those vast mountains of
stone now existing? All the coal, sulphur, and bitumen, now known, does
not form the 100,000 part of the materials deposited within one quarter
of a mile under the surface of the earth; if, therefore, they were, as
his hypothesis demands, carried off and mixed with the other materials,
and not formed in vast and separate collections, they could never
occasion, by their combustion, a heat capable of producing the smallest
effect, much less those gigantic effects which he requires."
Here is a comparative estimate formed between two things which have not
any necessary relation; these are, the quantity of combustible materials
found in the earth, on the one hand, and the quantity which is supposed
necessary for hardening and consolidating strata, on the other. If this
earth has been consolidated by the burning of combustible materials,
there must have been a superfluity, so far as there is a certain
quantity of these actually found unconsumed in the strata of the earth.
Our author's conclusion is the very opposite; let us then see how he
is to form his argument, by which he proves that the supposition of
subterraneous heat for hardening bodies is gratuitous and unnecessary,
as being inconsistent with my theory.
According to my theory, the strata of this earth are composed of the
materials which came from a former earth; particularly these combustible
strata that contain plants which must have grown upon the land. Let
us then suppose the subterraneous fire supplied with its combustible
materials from this source, the vegetable bodies growing upon the
surface of the land. Here is a source provided for the supplying of
mineral fire, a source which is inexhaustible or unlimited, unless
we are to circumscribe it with regard to time, and the necessary
ingredients; such as the matter of light, carbonic matter, and the
hydrogenous principle. But it is not upon any deficiency of this kind
that our author founds his estimate; it is upon the superfluity of
combustible materials which is actually found in this earth, after it
had been properly consolidated and raised above the surface of the sea.
This is a method of reasoning calculated to convince only those who do
not understand it; it is as if we should conclude that a person had died
of want, because he had left provision behind him. Our author certainly
means to employ nothing but the combustible minerals of the present
earth, in feeding the subterraneous fire which is to concoct a future
earth; in that case, I will allow that his provision is deficient; but
this is not my theory.
I am not here to enter into any argument concerning subterraneous
fire; the reader will find, in the foregoing theory, my reasons for
concluding, That subterraneous fire had existed previous to, and ever
since, the formation of this earth,--that it exists in all its vigour
at this day,--that there is, in the constitution of this earth, a
superfluity of subterranean heat,--and that there is wisely provided a
proper remedy against any destructive effect to the system, that might
arise from that superabundant provision of this necessary agent. Had our
author attended to the ocular proof that we have of the actual existence
of subterraneous fire, and to the physical demonstrations which I have
given of the effects of heat in melting mineral bodies, he must have
seen that those arguments of his, with regard to the difficulty or
impossibility of procuring that fire, can only show the error of his
reasoning. I am far from supposing that my theory may be free from
inconsistency or error; I am only maintaining that, in all his confident
assertions, this author has not hitherto pointed any of these out.
So far I have answered our author's objections as to consolidation, and
I have given a specimen of his reasoning upon that subject; but with
regard to my Theory of the Earth, although simple fluidity, without
heat, would have answered the purpose of consolidating strata that had
been formed at the bottom of the sea, it was necessary to provide a
power for raising those consolidated strata from that low place to the
summits of the continents; now, in supposing heat to be the cause of
that fluidity which had been employed in the consolidation of those
submarine masses, we find a power capable of erecting continents, and
the only power, so far as I see, which natural philosophy can employ
for that purpose. Thus I was led, from the consolidation of strata, to
understand the nature of the elevating power, and, from the nature of
that power, again to understand the cause of fluidity by which the rocks
and stones of this earth had been consolidated.
Having thus, without employing the evidence of any fire or _burning_,
been necessarily led to conclude an extreme degree of heat exerted in
the mineral regions, I next inquire how far there are any appearances
from whence we might conclude whether that active subterraneous power
still subsists, and what may be the nature of that power. When first I
conceived my theory, naturalists were far from suspecting that basaltic
rocks were of volcanic origin; I could not then have employed an
argument from these rocks as I may do now, for proving that the fires,
which we see almost daily issuing with such force from volcanos, are a
continuation of that active cause which has so evidently been exerted
in all times, and in all places, so far as have been examined of this
earth.
With regard to the degree of heat in that subterraneous fire, our
author, after proving that combustible materials would not burn in the
mineral regions, then says, that suppose they were to burn, this would
be "incapable of forming a heat even equal to that of our common
furnaces, as Mr Dolomieu has clearly shown to be the case with respect
to volcanic heat." The place to which he alludes, I believe to be that
which I have quoted from the Journal de Physique (Part I. page 139) to
which I here beg leave to refer the reader. After what I have already
said, this subject will appear to be of little concern to me; but, it
must be considered, that my object, in these answers, is not so much to
justify the theory which I have given, as it is to remove that prejudice
which, to those who are not master of chemical and mineral subjects,
will naturally arise from the opinion or authority of a scientific man,
and a chemist; therefore, I think it my business to show how much he
has misconceived the matter which he treats of, and how much he
misunderstands the subject of my theory.
Mr Dolomieu alleges that the volcanic fire operates in the melting of
bodies, not by the intensity of its heat, which is the means employed by
us in our operations, but in the long continuance of its action. But in
that proposition, this philosopher is merely giving us his opinion; and,
this opinion our author mistakes, I suppose, for the fact on which that
opinion had been (perhaps reasonably) founded. The reader will see, in
the place quoted, or in the _avant-propos_ to his _Memoire sur les Iles
Ponces_, the fact to be this; That the Chevalier Dolomieu finds those
bodies which we either cannot melt in our fires, or which we cannot melt
without changing them by calcination and vitrification, he finds, I say,
these substances had actually been melted with his lavas; he also finds
those substances, which are necessarily dissipated in our fires, to have
been retained in those melted mineral substances. Had our author quoted
the text, instead of giving us his own interpretation, he could not have
offered a stronger confirmation of my theory; which certainly is not
concerned with the particular intensity of volcanic fire, and far less
with what may be the opinion of any naturalist with regard to that
intensity, but only with the efficacy of that volcanic heat for the
melting of mineral substances. Now this efficacy of volcanic fire, so
far as we are to found upon the authority given on this occasion, is
clearly confirmed by the observations of a most intelligent mineralist,
and one who is actually a patron of the opposite theory to that which I
have given. This being the state of the case, Must I not conclude, that
our author has misunderstood the subject, and that he has been led to
give a mutilated opinion of Mr Dolomieu, in order to refute my theory,
when either the entire opinion, or the facts on which the opinion had
been founded, would have confirmed it?
I have thus endeavoured to put in its true light a species of reasoning,
which, while it assumes the air and form of that inductive train of
thought employed by men of science for the investigation of nature, is
only fit to mislead the unwary, and, when closely examined, will appear
to be inconsequential or unfounded. How mortifying then to find, that
one may be employed almost a lifetime in generalising the phenomena of
nature, or in gathering an infinity of evidence for the forming of a
theory, and that the consequence of this shall only be to give offence,
and to receive reproach from those who see not things in the same
light!--While man has to learn, mankind must have different opinions.
It is the prerogative of man to form opinions; these indeed are often,
commonly I may say, erroneous; but they are commonly corrected, and it
is thus that truth in general is made to appear.
I wrote a general Theory for the inspection of philosophers, who
doubtless will point out its errors; but this requires the study of
nature, which is not the work of a day; and, in this political age, the
study of nature seems to be but little pursued by our philosophers. In
the mean time, there are, on the one hand, sceptical philosophers, who
think there is nothing certain in nature, because there is misconception
in the mind of man; on the other hand, there are many credulous
amateurs, who go to nature to be entertained as we go to see a
pantomime: But there are also superficial reasoning men, who think
themselves qualified to write on subjects on which they may have read
in books,--subjects which they may have seen in cabinets, and which,
perhaps, they have just learned to name; without truly knowing what they
see, they think they know those regions of the earth which never can be
seen; and they judge of the great operations of the mineral kingdom,
from having kindled a fire, and looked into the bottom of a little
crucible.
In the Theory of the Earth which was published, I was anxious to warn
the reader against the notion that subterraneous heat and fusion could
be compared with that which we induce by our chemical operations
on mineral substances here upon the surface of the earth; yet,
notwithstanding all the precaution I had taken, our author has bestowed
four quarto pages in proving to me, that our fires have an effect upon
mineral substances different from that of the subterraneous power which
I would employ.
He then sets about combining metals with sulphur in the moist way, as if
that were any more to his purpose than is the making of a stalactite for
the explanation of marble. Silver and lead may be sulphurated, as he
says, with hepatic gas; but, Has the sulphurated solid ores of those
metals, and that of iron, been formed in the moist way, as in some
measure they may be by the fusion of our fires? But, even suppose that
this were the case, Could that explain a thousand other appearances
which are inconsistent with the operation of water? We see aerated lead
dissolved in the excavations of our mines, and again concreted by the
separation of the evaporated solvent, in like manner as stalactical
concretions are made of calcareous earth; but, so far from explaining
mineral appearances, as having had their concretions formed in the same
manner, here is the most convincing argument against it; for, among the
infinite variety of mineral productions which we find in nature, Why
does no other example of aqueous concretion ever occur upon the surface
of the earth except those which we understand so well, and which we
therefore know cannot be performed in the bodies of strata not exposed
to the evaporation of the solvent, a circumstance which is necessary.
I have given a very remarkable example of mineral fusion, in reguline
manganese, (as the reader will see in page 68.) It is not that this
example is more to the purpose of my theory than what may be found in
every species of stone; but this example speaks so immediately to
the common sense of mankind, (who are often convinced by a general
resemblance of things, when they may not see the force of demonstration
from an abstract principle) that I thought it deserved a place on that
account, as well as being a curious example, But more particularly to my
antagonist, who has been pleased (very improperly indeed) to try some
part of my theory in the fire, here is an example which should have
been absolutely in point, and without any manner of exception:--Has he
acknowledged this?--No; he has, on the contrary, endeavoured to set this
very example aside.
On this occasion, he says, "Manganese has been found in a reguline state
by M. de la Peyrouse, and in small grains, as when produced by fire.
True; but it was mixed with a large quantity of iron, which is often,
found in that form without any suspicion of fusion. A fire capable of
melting quartz might surely produce it in larger masses." We have here
a kind of two arguments, for removing the effect of this example; and I
shall consider them separately.
The first of these is, the not being suspected of having been in fusion;
now, if this were to be admitted as an argument against the igneous
origin of stony substances, it might have superseded the adducing of any
other, for it is applicable perhaps to every mineral; but we must here
examine the case more minutely.
This argument, of the manganese being in a mine of iron, if I understand
it rightly, amounts to this, that, as iron ore is not suspected of
having been melted, therefore, we should doubt the manganese having been
so. If this be our author's meaning, it is not the fair conclusion which
the case admits of; for, so far as the manganese appears evidently to
have been in a melted state, the iron ore should be _suspected_ of
having been also in fusion, were there no other evidence of that fact.
In science, however, it is not suspicion that should be employed in
physical investigation; the question at present is; If the phenomena of
the case correspond to the conclusion which the intelligent mineralist,
who examined them, has formed? and, to this question, our author gives
no direct answer. He says, _iron is often found in that form without any
suspicion of fusion_. This is what I am now to answer.
The form in which the manganese appears is one of the strongest proofs
of those masses having been in fusion; and, if iron should ever be found
in that form, it must give the same proof of mineral fusion as this
example of manganese; let us then see the nature of this evidence. The
form of the manganese is that of a fluid body collecting itself into a
spherical figure by the cohesion or attraction of its particles, so far
as may be admitted by other circumstances; but, being here refilled by
the solid part on which it rests, this spherical body is flattened by
the gravitation of its substance. Now here is a regular form, which
demonstrates the masses to have been in the state of fusion; for, there
is no other way in which that form of those reguline masses could have
been induced.
There now remains to be considered what our author has observed
respecting the intensity of the fire and size of the masses. "A
fire capable of melting quartz might surely produce it (meaning the
manganese) in larger masses." M. de la Peyrouse says, that those masses
were in all respects as if formed by art, only much larger, as the
powers of nature exceed those of our laboratories. What then is it that
is here meant to be disputed? We are comparing the operation of nature
and that of art, and these are to be judged of by the product which we
examine; but the quantity, in this case, or the size of the masses,
makes no part of the evidence, and therefore is here most improperly
mentioned by our author. With regard again to the nature of the fire by
which the fusion had been produced, he is much mistaken if he imagines
that the reduction of the reguline or metallic manganese depends upon
the intensity of the heat; it depends upon circumstances proper for the
separation of the oxygenating principle from the calx, in like manner as
the calcination of calcareous spar must depend upon circumstances proper
for allowing the separation of the carbonic acid or fixed air.
But do not let us lose sight of our proper subject, by examining things
foreign or not so immediately to the purpose. We are only inquiring if
those flattened spheres of native manganese had been formed by water, or
if it were by fusion; for, our author agrees that there is no other way.
Why then does he endeavour to evade giving a direct answer, and fly away
to consider the quantity of the product, as if that had any thing to do
with, the question, or as if that quantity were not sufficient, neither
of which is the case. In short, our author's whole observation, on this
occasion, looks as if he were willing to destroy, by insinuation, the
force of an argument which proves the theory of mineral fusion; and that
he wishes to render doubtful, by a species of sophistry, what in fair
reasoning he cannot deny.
Our author has written upon the subject of phlogiston; one would suppose
that he should be well acquainted with inflammable bodies at least; let
us see then what he has to observe upon that subject. He quotes from
my Theory, that spar, quartz, pyrites, crystallised upon or near each
other, and adhering to coal, or mixed with bitumen, etc. are found;
circumstances that cannot be explained in the hypothesis of solution
in the moist way.--He then answers;--"Not exactly, nor with certainty;
which is not wonderful: But they are still less explicable in the
hypothesis of dry solution, as must be apparent from what has been
already said. How coal, an infusible substance, could be spread into
strata by mere heat, is to me incomprehensible."--It is only upon the
last sentence that I am here to remark: This, I believe, will be a
sufficient specimen of our author's understanding, with regard at least
to my Theory which he is here examining.
The reader will see what I have said upon the subject of coal, by
turning back to the second section of the preceding chapter. I had given
almost three quarto pages upon that subject, endeavouring to explain how
all the different degrees of _infusibility_ were produced, by means of
heat and distillation, in strata which had been originally more or less
oily, bituminous, and _fusible_; and now our author says, that it is
incomprehensible to him, how coal, _an infusible substance_, could be
spread into strata by mere heat.--So it truly may, either to him or to
any other person; but, it appears to me almost as incomprehensible, how
a person of common understanding should read my Dissertation, and impute
to it a thing so contrary to its doctrine.
Nothing can better illustrate the misconceived view that our author
seems to have taken of the two opposite theories, (_i. e_. of
consolidation by means of heat, and by means of water alone,) than
his observation upon the case of mineral alkali. To that irrefragable
argument (which Dr Black suggested) in proof of this substance having
been in a state of fusion in the mineral regions, our author makes the
following reply; "What then will our author say of the vast masses
of this salt which are found with their full quantity of water of
crystallization?"--There is in this proposition, insignificant as it may
seem, a confusion of ideas, which it certainly cannot be thought worth
while to investigate; but, so far as the doctrine of the aqueous theory
may be considered as here concerned, it will be proper that I should
give some answer to the question so triumphantly put to me.
Our author is in a mistake in supposing that Dr Black had written any
thing upon the subject; he had only suggested the argument of this
example of mineral alkali to me, as I have mentioned; and, the use I
made of that argument was to corroborate the example I had given of sal
gem. If, therefore, our author does not deny the inference from the
state of that mineral alkali, his observation upon it must refer to
something which this other example of his is to prove on the opposite
side, or to support the aqueous instead of the igneous theory; and, this
is a subject which I am always willing to examine in the most impartial
manner, having a desire to know the true effect of aqueous solution in
the consolidation of mineral bodies, and having no objection to allow it
any thing which it can possibly produce, although denying that it can do
every thing, as many mineralists seem to think.
The question, with regard to this example of our author's of a mineral
alkali with its water of crystallization, must be this, Whether those
saline bodies had been concreted by the evaporation of the aqueous
solvent with which they had been introduced, or by the congelation of
that saline substance from a fluid state of fusion; for, surely, we are
not to suppose those bodies to have been created in the place and state
in which we find them. With regard to the evaporation or separation
of the aqueous solvent, this may be easily conceived according to the
igneous theory; but, the aqueous theory has not any means for the
producing of that effect in the mineral regions, which is the only place
we are here concerned with. Therefore, this example of a concreted body
of salt, whatever it may prove in other respects, can neither diminish
the evidence of my Theory with regard to the igneous origin of stony
substances, nor can it contribute to support the opposite supposition of
an aqueous origin to them.
But to show how little reason our author had for exulting in that
question which he so confidently proposed in order to defeat my
argument, let us consider this matter a little farther. I will for a
moment allow the aqueous theory to have the means for separating
the water from the saline solution, and thus to concrete the saline
substance in the bowels of the earth; this concretion then is to be
examined with a view to investigate the last state of this body, which
is to inform us with regard to those mineral operations. But, our author
has not mentioned whether those masses appear to have been crystallised
from the aqueous solution, or if they appear to have been congealed from
the melted state of their _aqueous fusion_.--Has he ever thought of
this? Now this is so material a point in the view with which that
example has been held out to us, that, without showing that this salt
had crystallised from the solution, he has no right to employ it as an
example; and if, on the other hand, it should appear to have simply
congealed from the state of aqueous fusion, then, instead of answering
the purpose for which our author gave it, it would refute his
supposition, as certainly as the example which I have given.
So far I have reasoned upon the supposition of this alkali, with its
water of crystallization, being truly a mineral concretion; but, I see
no authority for such a supposition: It certainly may be otherwise;
and, in that case, our author would have no more right to give it as an
example in opposition to Dr Black's argument, than he would have to give
the crystallization of sea-salt, on Turk's Island, in opposition to the
example which I had given, of the salt rock, at Northwych in Cheshire,
having been in the state of fusion.
It certainly was incumbent on our author to have informed us, if those
masses of salt were found in, what may be properly termed, their mineral
state; or, if the state in which they are found at present had been
produced by the influences of the atmosphere, transforming that saline
substance from its mineral state, as happens upon so many other
occasions; I am inclined to suspect that this last is truly the case.
It may be thought illiberal in me to suppose a natural philosopher thus
holding out an example that could only serve to lead us into error, or
to mislead our judgment with regard to those two theories which is the
subject of consideration. This certainly would be the case, almost
on any other occasion; but, when I find every argument and example,
employed in this dissertation, to be either unfounded or misjudged,
Whether am I to conclude our author, on this occasion, to be consistent
with himself, or not?
I have but one article more to observe upon. I had given, as I thought,
a kind of demonstration, from the internal evidence of the stone, that
granite had been in the fluid state of fusion, and had concreted by
crystallization and congelation from that melted state. This no doubt
must be a stumbling block to those who maintain that granite mountains
are the primitive parts of our earth; and who, like our author, suppose
that "things may have been originally, as at present, in a solid state."
It must also be a great, if not an invincible obstacle in the way of the
aqueous theory, which thus endeavours to explain those granite veins
that are found traversing strata, and therefore necessarily of a
posterior formation.
To remove that obstacle in the way of the aqueous theory, or to carry
that theory over the obstacle which he cannot remove, our author
undertakes to refute my theory with regard to the igneous origin of
stony substances, by giving an example of granite formed upon the
surface of the earth by means of water, or in what is called the
moist way; and he closes his Dissertation with this example as an
_experimentum crucis_. It is therefore necessary that I take this
demonstration of our author into particular consideration; for, surely,
independent of our controversy, which is perhaps of little moment, here
is the most interesting experiment, as it is announced, that mineralogy
could be enriched with.
"To close this controversy," says our author, "I shall only add,
that granite, recently formed in the moist way, has been frequently
found."--Of that remarkable event, however, he has selected only one
example. This is to be found upon the Oder; and the authority upon which
our author has given it, is that of Lasius Hartz.
The formation of a granite stone, from granite sand, by means of water,
is inconsistent with our chemical knowledge of those mineral substances
which constitute that stone; it is repugnant to the phenomena which
appear from the inspection of the natural bodies of this kind; and it
is directly contrary to the universal experience in granite countries,
where, instead of any thing concreting, every thing is going into
decay, from the loose stones and sand of granite, to the solid rock and
mountains which are always in a state of degradation. Therefore, to have
any credit given to such a story, would require the most scientific
evidence in its favour. Now, in order that others may judge whether this
has been the case in this example, I will transcribe what our author has
said upon the subject; and then I will give the view in which it appears
to me.
He says, "a mole having been constructed in the Oder in the year 1723,
350 feet long, 54 feet in height, 144 feet broad at bottom, and 54 at
the top, its sides only were granite, without any other cement than
moss; the middle space was entirely filled with granite sand. In a short
time this concreted into a substance so compact as to be impenetrable by
water."--Here is an example, according to our author, of _granite formed
in the moist way_. But now, I must ask to see the evidence of that fact;
for, from what our author has told us, I do not even see reason to
conclude that there was the least concretion, or any stone formed at
all. A body of sand will be _so compacted as to be impenetrable by
water_, with the introduction of a very little mud, and without any
degree of concretion; muddy water, indeed, cannot be made to pass
through such a body without compacting it so; and this every body finds,
to their cost, who have attempted to make a filter of that kind.
But I shall suppose Lasius has informed our author that there had been
a petrifaction in this case; and, before I admit this example of the
formation of granite, I must ask what sort of a granite it was;--whether
of two, three, or four ingredients; and, how these were disposed. If,
again, it were not properly a granite, but a stone formed of granite
sand, What is the cementing substance?--Is it quartz, felt-spar, mica,
or schorl?--or, Was it calcareous? If our author knows any thing about
these necessary questions, Why has he not informed us, as minutely as
he has done with regard to the dimensions of the mole, with which we
certainly are less concerned? If, again, he knows no more about the
matter than what he has informed us of, he must have strangely imposed
upon himself, to suppose that he was giving us an example of the
_formation of granite in the moist way_, when he has only described an
effectual way of retaining water, by means of sand and mud.
CHAP. III.
Of Physical Systems, and Geological Theories, in general.
In the first chapter I have given a general theory of the earth,
with such proofs as I thought were sufficient for the information of
intelligent men, who might satisfy themselves by examining the facts on
which the reasoning in that theory had been founded.
In the second chapter, I have endeavoured to remove the objections which
have been made to that theory, by a strenuous patron of the commonly
received opinion of mineralogists and geologists,--an opinion which, if
not diametrically opposite, differs essentially from mine. But now I am
to examine nature more particularly, in order to compare those different
opinions with the actual state of things, on which every physical theory
must be founded. Therefore, the opinions of other geologists should be
clearly stated, that so a fair comparison may be made of theories which
are to represent the system of this earth.
Now, if I am to compare that which I have given as a theory of the
earth, with the theories given by others under that denomination, I
find so little similarity, in the things to be compared, that no other
judgment could hence be formed, perhaps, than that they had little or no
resemblance. I see certain treatises named Theories of the Earth; but, I
find not any thing that entitles them to be considered as such, unless
it be their endeavouring to explain certain appearances which are
observed in the earth. That a proper theory of the earth should explain
all those appearances is true; but, it does not hold, conversely, that
the explanation of an appearance should constitute a theory of the
earth. So far as the theory of the earth shall be considered as the
philosophy or physical knowledge of this world, that is to say, a
general view of the means by which the end or purpose is attained,
nothing can be properly esteemed such a theory unless it lead, in some
degree, to the forming of that general view of things. But now, let us
see what we have to examine in that respect.
We have, first, Burnet's Theory of the Earth. This surely cannot be
considered in any other light than as a dream, formed upon the poetic
fiction of a golden age, and that of iron which had succeeded it; at the
same time, there are certain appearances in the earth which would, in a
partial view of things, seem to justify that imagination. In Telliamed,
again, we have a very ingenious theory, with regard to the production of
the earth above the surface of the sea, and of the origin of those
land animals which now inhabit that earth. This is a theory which has
something in it like a regular system, such as we might expect to find
in nature; but, it is only a physical romance, and cannot be considered
in a serious view, although apparently better founded than most of that
which has been wrote upon the subject.
We have then a theory of a very different kind; this is that of the
Count de Buffon. Here is a theory, not founded on any regular system,
but upon an irregularity of nature, or an accident supposed to have
happened to the sun. But, are we to consider as a theory of the earth,
an accident by which a planetary body had been made to increase the
number of these in the solar system? The circumvolution of a planetary
body (allowing it to have happened in that manner) cannot form the
system of a world, such as our earth exhibits; and, in forming a theory
of the earth, it is required to see the aptitude of every part of this
complicated machine to fulfil the purpose of its intention, and not to
suppose the wise system of this world to have arisen from, the cooling
of a lump of melted matter which had belonged to another body. When
we consider the power and wisdom that must have been exerted in the
contriving, creating, and maintaining this living world which sustains
such a variety of plants and animals, the revolution of a mass of dead
matter according to the laws of projectiles, although in perfect wisdom,
is but like a unite among an infinite series of ascending numbers.
After the theory of that eloquent writer, founded on a mere accident, or
rather the error of a comet which produced the beautiful system of this
world, M. de Luc, in his Theory of the earth, has given us the history
of a disaster which befell this well contrived world;--a disaster which
caused the general deluge, and which, without a miracle, must have
undone a system of living beings that are so well adapted to the present
state of things. But, surely, general deluges form no part of the theory
of the earth; for, the purpose of this earth is evidently to maintain
vegetable and animal life, and not to destroy them.
Besides these imaginary great operations in the natural history of this
earth, we have also certain suppositions of geologists and mineralists
with regard to the effect of water, for explaining to us the
consolidation of the loose materials of which the strata of the earth
had been composed, and also for producing every other appearance, or any
which shall happen to occur in the examination of the earth, and require
to be explained. That this is no exaggerated representation, and
that this is all we have as a theory, in the suppositions of those
geologists, will appear from the following state of the case.
They suppose water the agent employed in forming the solid bodies of the
earth, and in producing those crystallised bodies which appear in
the mineral kingdom. That this is a mere supposition will appear by
considering; first, that they do not know how this agent water is to
operate in producing those effects; nor have they any direct proof
of the fact which is alleged, from a very fallaceous analogy; and,
secondly, that they cannot tell us where this operation is to be
performed. They cannot say that it is in the earth above the level of
the sea: for, the same appearances are found as deep as we can examine
below that level; besides, we see that water has the opposite effect
upon the surface of the earth, through which it percolates dissolving
soluble substances, and thus resolving solid bodies in preparing soil
for plants. If, again, it be below the level of the sea, that strata of
the earth are supposed to be consolidated by the infiltration of that
water which falls from the heavens; this cannot be allowed, so far as
whatever of the earth is bibulous, in that place, must have been always
full of water, consequently cannot admit of that supposed infiltration.
But allowing those suppositions to be true, there is nothing in them
like a theory of the earth,--a theory that should bring the operations
of the world into the regularity of ends and means, and, by generalizing
these regular events, show us the operation of perfect intelligence
forming a design; they are only an attempt to show how certain things,
which we see, have happened without any perceivable design, or without
any farther design than this particular effect which we perceive. If we
believe that there is almighty power, and supreme wisdom employed for
sustaining that beautiful system of plants and animals which is so
interesting to us, we must certainly conclude, that the earth, on which
this system of living things depends, has been constructed on principles
that are adequate to the end proposed, and procure it a perfection which
it is our business to explore. Therefore, a proper system of the earth
should lead us to see that wise contraction, by which this earth is made
to answer the purpose of its intention and to preserve itself from every
accident by which the design of this living world might be frustrated as
this world is an active scene, or a material machine moving in all its
parts, we must see how this machine is so contrived, as either to have
those parts to move without wearing and decay, or to have those parts,
which are wasting and decaying, again repaired.
A rock or stone is not a subject that, of itself, may interest a
philosopher to study; but, when he comes to see the necessity of those
hard bodies, in the constitution of this earth, or for the permanency
of the land on which we dwell, and when he finds that there are means
wisely provided for the renovation of this necessary decaying part, as
well as that of every other, he then, with pleasure, contemplates this
manifestation of design, and thus connects the mineral system of
this earth with that by which the heavenly bodies are made to move
perpetually in their orbits. It is not, therefore, simply by seeing the
concretion of mineral bodies that a philosopher is to be gratified in
his his intellectual pursuit, but by the contemplation of that system in
which the necessary resolution of this earth, while at present it serves
the purpose of vegetation, or the fertility of our soil, is the very
means employed in furnishing the materials of future land.
It is such a view as this that I have endeavoured to represent in the
theory which I have given. I have there stated the present situation of
things, by which we are led to perceive a former state; and, from that
necessary progress of actual things, I have concluded a certain system
according to which things will be changed, without any accident or
error. It is by tracing this regular system in nature that a philosopher
is to perceive the wisdom with which this world has been contrived; but,
he must see that wisdom founded upon the aptitude of all the parts to
fulfil the intention of the design; and that intention is to be deduced
from the end which is known to be attained. Thus we are first to reason
from effect to cause, in seeing the order of that which has already
happened; and then, from those known causes, to reason forwards, so as
to conceive that which is to come to pass in time. Such would be the
philosophy of this earth, formed by the highest generalisation
of phenomena, a generalisation which had required the particular
investigation of inductive reasoning.
That no such theory as this, founded upon water as an agent operating in
the changes of this earth, has yet appeared, will, I believe be easily
allowed. With regard again to fire as an agent in the mineral operations
of this earth, geologists have formed no consistent theory. They see
volcanoes in all the quarters of the globe, and from those burning
mountains, they conjecture other mountains have been formed. But a
burning mountain is only a matter of fact; and, they have not on this
formed any general principle, for establishing what may be called a
theory of the earth. Those who have considered subterraneous fires as
producing certain effects, neither know how these have been procured,
nor do they see the proper purpose for which they are employed in the
system of this world. In this case, the agent fire is only seen as
a destructive element, in like manner as deluges of water have been
attributed by others to changes which have happened in the natural state
of things. These operations are seen only as the accidents of nature,
and not as part of that design by which the earth, which is necessarily
wasted in the operations of the world, is to be repaired.
So far from employing heat or subterraneous fire as an agent in the
mineral operations of the earth, the volcanic philosophers do not
even attempt to explain upon that principle the frequent nodules of
calcareous, zeolite, and other spatose and agaty substances, in those
basaltic bodies which they consider as lavas. Instead then of learning
to see the operation of heat as a general principle of mineral
consolidation and crystallization, the volcanic philosophers endeavour
to explain those particular appearances, which they think inconsistent
with fusion, by aqueous infiltration, no otherwise than other
mineralists who do not admit the igneous origin of those basaltic
bodies. Thus, that great agent, subterraneous heat, has never been
employed by geologists, as a general principle in the theory of the
earth; it has been only considered as an occasional circumstance, or as
the accident of having certain mineral bodies, which are inflammable,
kindled in the earth, without so much as seeing how that may be done.
This agent heat, then, is a new principle to be employed in forming a
theory of the earth; a principle that must have been in the constitution
of this globe, when contrived to subsist as a world, and to maintain
a system of living bodies perpetuating their species. It is therefore
necessary to connect this great mineral principle, subterraneous fire
or heat, with the other operations of the world, in forming a general
theory. For, whether we are to consider those great and constant
explosions of mineral fire as a principal agent in the design, or only
as a casual event depending upon circumstances which give occasion to an
operation of such magnitude, here is an object that must surely have its
place in every general theory of the earth.
In examining things which actually exist, and which have proceeded in a
certain order, it is natural to look for that which had been first; man
desires to know what had been the beginning of those things which now
appear. But when, in forming a theory of the earth, a geologist shall
indulge his fancy in framing, without evidence, that which had preceded
the present order of things, he then either misleads himself, or writes
a fable for the amusement of his reader. A theory of the earth, which
has for object truth, can have no retrospect to that which had preceded
the present order of this world; for, this order alone is what we have
to reason upon; and to reason without data is nothing but delusion. A
theory, therefore, which is limited to the actual constitution of this
earth, cannot be allowed to proceed one step beyond the present order of
things.
But, having surveyed the order of this living world, and having
investigated the progress of this active scene of life, death and
circulation, we find ample data on which to found a train of the most
conclusive reasoning with regard to a general design. It is thus that
there is to be perceived another system of active things for the
contemplation of our mind;--things which, though not immediately within
our view, are not the less certain in being out of our sight; and things
which must necessarily be comprehended in the theory of the earth, if we
are to give stability to it as a world sustaining plants and animals.
This is a mineral system, by which the decayed constitution of an earth,
or fruitful surface of habitable land, may be continually renewed in
proportion as it is wasted in the operations of this world.
It is in this mineral system that I have occasion to compare the
explanations, which I give of certain natural appearances, with the
theories or explanations which have been given by others, and which are
generally received as the proper theory of those mineral operations. I
am, therefore, to examine those different opinions, respecting the
means employed by nature for producing particular appearances in the
construction of our land, appearances which must be explained in some
consistent mineral theory.
These appearances may all be comprehended under two heads, which are now
to be mentioned, in order to see the importance of their explanation, or
purpose which such an explanation is to serve in a theory of the earth.
The first kind of these appearances is that of known bodies which we
find composing part of the masses of our land, bodies whose natural
history we know, as having existed in another state previous to the
composition of this earth where they now are found; these are the
relicts or parts of animal and vegetable bodies, and various stony
substances broken and worn by attrition, all which had belonged to a
former earth. By means of these known objects, we are to learn a great
deal of the natural history of this earth; and, it is in tracing that
history, from where we first perceive it, to the present state of
things, that forms the subject of a geological and mineralogical theory
of this earth. But, we are more especially enabled to trace those
operations of the earth, by means of the second kind of appearances,
which are now to be mentioned.
These again are the evident changes which those known bodies have
undergone, and which have been induced upon such collected masses of
which those bodies constitute a part. These changes are of three sorts;
_first_, the solid state, and various degrees of it, in which we now
find those masses which had been originally formed by the collection of
loose and incoherent materials; _secondly_, the subsequent changes which
have evidently happened to those consolidated masses which have been
broken and displaced, and which have had other mineral substances
introduced into those broken and disordered parts; and, _lastly_, that
great change of situation which has happened to this compound mass
formed originally at the bottom of the sea, a mass which, after being
consolidated in the mineral region, is now situated in the atmosphere
above the surface of the sea.
In this manner we are led to the system of the world, or theory of the
earth in general; for, that great change of situation, which our land
has undergone, cannot be considered as the work of accident, or any
other than an essential part in the system of this world. It is
therefore a proper view of the necessary connection and mutual
dependence of all those different systems of changing things that forms
the theory of this earth as a world, or as that active part of nature
which the philosophy of this earth has to explore. The animal system is
the first or last of these; next comes the vegetable system, on which
the life of animals depends; then comes the system of this earth,
composed of atmosphere, sea, and land, and comprehending the various
chemical, mechanical, and meteorologically operations which take place
upon that surface where vegetation must proceed; and, lastly, we have
the mineral system to contemplate, a system in which the wasting surface
of the earth is employed in laying the foundation of future land within
the sea, and a system in which the mineral operations are employed in
concocting that future land.
Now, such must surely be the theory of this earth, if the land is
continually wasting in the operations of this world; for, to acknowledge
the perfection of those systems of plants and animals perpetuating their
species, and to suppose the system of this earth on which they must
depend, to be imperfect, and in time to perish, would be to reason
inconsistently or absurdly. This is the view of nature that I would wish
philosophers to take; but, there are certain prejudices of education or
prepossession of opinion among them to be overcome, before they can be
brought to see those fundamental propositions,--the wasting of the land,
and the necessity of its renovation by the co-operation of the mineral
system. Let us then consider how men of science, in examining the
mineral state of things, and reasoning from those appearances by which
we are to learn the physiology of this earth, have misled themselves
with regard to physical causes, and formed certain mineralogical and
geological theories, by which their judgment is so perverted, in
examining nature, as to exclude them from the proper means of correcting
their first erroneous notions, or render them blind to the clearest
evidence of any other theory that is proposed.
When men of science reason upon subjects where the ideas are distinct
and definite, with terms appropriated to the ideas, they come to
conclusions in which there is no difference of opinion. It is otherwise
in physical subjects, where things are to be assimilated, in being
properly compared; there, things are not always compared in similar and
equal circumstances or conditions; and there, philosophers often draw
conclusions beyond the analogy of the things compared, and thus judge
without data. When, for example, they would form the physical induction,
with regard to the effect of fire or water upon certain substances in
the mineral regions, from the analogy of such events as may be observed
upon the surface of the earth, they are apt to judge of things acting
under different circumstances or conditions, consequently not producing
similar effects; in which case, they are judging without reason, that
is, instead of inductive reasoning from actual data or physical truth,
they are forming data to themselves purely by supposition, consequently,
so far as these, imagined data may be wrong, the physical conclusion, of
these philosophers may be erroneous.
It is thus that philosophers have judged, with regard to the effects of
fire and water upon mineral substances below the bottom of the sea,
from what their chemistry had taught them to believe concerning bodies
exposed to those agents in the atmosphere or on the surface of the
earth. If in those two cases the circumstances were the same, or
similar, consequently the conditions of the action not changed, then,
the inductive reasoning, which they employ in that comparison, would be
just; but, so far as it is evidently otherwise, to have employed that
inductive conclusion for the explanation of mineral appearances, without
having reason to believe that those changed circumstances of the case
should not make any difference in the action or effect, is plainly to
have transgressed the rules of scientific reasoning; consequently,
instead of being a proper physical conclusion, it is only that imperfect
reasoning of the vulgar which, by comparing things not properly analysed
or distinguished, is so subject to be erroneous. This vague reasoning,
therefore, cannot be admitted as a part of any geological or mineral
theory. Now I here maintain, that philosophers have judged in no other
manner than by this false analogy, when they conclude that water is the
agent by which mineral concretions have been formed. But it will be
proper to state more particularly the case of that misunderstanding
among mineral philosophers.
In forming a geological theory, the general construction of this earth,
and the materials of which it is composed, are such visible objects, and
so evident to those who will take the pains to examine nature, that
here is a subject in which there cannot be any doubt or difference of
opinion. Neither can there be any dispute concerning the place and
situation of mass when it was first formed or composed; for, this is
clearly proved, from every concomitant circumstance, to have been at the
bottom of the sea. The only question in this case, that can be made, is,
How that mass comes now to be a solid body, and above the surface of the
sea in which it had been formed?
With regard to the last, the opinions of philosophers have been so
dissonant, so vague, and so unreasonable, as to draw to no conclusion.
Some suppose the land to be discovered by the gradual retreat of the
ocean, without proposing to explain to us from whence had come the known
materials of a former earth, which compose the highest summits of the
mountains in the highest continents of the earth. Others suppose the
whole of a former earth to have subsided below the bottom even of the
present sea, and together with it all the water of the former sea, from
above the summits of the present mountains, which had then been at the
bottom of the former sea. The placing of the bottom of the sea, or any
part of it, in the atmosphere so as to be dry land, is no doubt a great
operation to be performed, and a difficult task to be explained; but
this is only an argument the more for philosophers to agree in adopting
the most reasonable means.
But though philosophers differ so widely in that point, this is not the
case with regard to the concretion of mineral bodies; here mineralists
seem to be almost all of one mind, at the same time without any reason,
at least, without any other reason than that false analogy which they
have inconsiderately formed from the operations of the surface of this
earth. This great misunderstanding of mineralists has such an extensive
and baneful effect in the judging of geological theories, that it
will be proper here to explain how that has happened, and to shew the
necessity of correcting that erroneous principle before any just opinion
can be formed upon the subject.
Fire and water are two great agents in the system of this earth; it is
therefore most natural to look for the operation of those agents in the
changes which are made on bodies in the mineral regions; and as the
consolidated state of those bodies, which had been collected at the
bottom of the sea, may have been supposed to be induced either by
fusion, or by the concretion from a solution, we are to consider how far
natural appearance lead to the conclusion of the one or other of those
two different operations. Here, no doubt, we are to reason analogically
from the known power and effects of those great agents; but, we must
take care not to reason from a false analogy, by misunderstanding the
circumstances of the case, or not attending to the necessary conditions
in which those agents act.--We must not conclude that fire cannot burn
in the mineral regions because our fires require the ventilation of the
atmosphere; for, besides the actual exigence of mineral fire being a
notorious matter of fact, we know that much more powerful means _may_
be employed by nature, for that mineral purpose of exciting heat, than
those which we practise.--We must not conclude that mineral marble is
formed in the same manner as we see a similar stony substance produced
upon the surface of the earth, unless we should have reason to suppose
the analogy to be complete. But, this is the very error into which
mineral philosophers have fallen; and this is the subject which I am now
to endeavour to illustrate.
The manner in which those philosophers have deceived themselves when
reasoning upon the subject of mineral concretion, is this: They see,
that by means of water a stony substance is produced; and, this stony
body so much resembles mineral marble as to be hardly distinguishable in
certain cases. These mineral philosophers then, reasoning in the manner
of the vulgar, or without analysing the subject to its principle,
naturally attribute the formation of the mineral marble to a cause
of the same sort; and, the mineral marble being found so intimately
connected with all other mineral bodies, we must necessarily conclude,
in reasoning according to the soundest principles, that all those
different substances had been concreted in the same manner. Thus, having
once departed one step from the path of just investigation, our physical
science is necessarily bewildered in the labyrinth of error. Let us
then, in re-examining our data, point out where lies that first devious
step which had been impregnated with fixed air, or carbonic acid gas,
(as it is called), dissolves a certain portion of mild calcareous
earth or marble; consequently such acidulated water, that is, water
impregnated with this gas, will, by filtrating through calcareous
substances, become saturated with that solution of marble; and, this
solution is what is called a _petrifying water_. When this solution is
exposed to the action of the atmosphere, the acid gas, by means of which
the stony substance is dissolved, evaporates from the solution, in
having a stronger attraction for the atmospheric air; it is then that
the marble, or calcareous substance, concretes and crystallises,
separating from the water in a sparry state, and forming a very solid
stone by the successive accretion from the solution, as it comes to
be exposed to the influence of the atmosphere in flowing over the
accumulating body. Here is the source of their delusion; for, they do
not distinguish properly the case of this solution of a stony substance
concreting by means of the separation of its solvent, and the case of
such a solution being in a place where that necessary condition cannot
be supposed to exist; such as, e.g., the interstices among the particles
of sand, clay, etc. deposited at the bottom of the sea, and accumulated
in immense stratified masses.
No example can better illustrate how pernicious it is to science to have
admitted a false principle, on which a chain of reasoning is to proceed
in forming a theory. Mineral philosophers have founded their theory upon
that deceitful analogy, which they had concluded between the stalactical
concretions of petrifying waters and the marble formed in the mineral
regions; thus, blinded by prejudice, they shut the door against the
clearest evidence; and it is most difficult to make them see the error
of their principle. But this is not to be wondered at, when we consider
how few among philosophising men remount to the first principles of
their theory; and, unless they shall thus remount to that first step,
in which the concreting operation of a dissolved stony substance
is supposed to take place without the necessary conditions for the
petrifying operation, it is impossible to be convinced that their
theory, thus formed with regard to mineral concretion, is merely
supposition, and has no foundation in matter of fact from whence it
should proceed.
But this is not all; for, even supposing their theory to be well founded
and just, it is plainly contradicted by natural appearances. According
to that theory of aqueous consolidation, all the stratified bodies, of
which this earth in general consists, should be found in the natural
order of their regular formation; but, instead of this, they are found
every where disturbed in that order more or less; in many places this
order and regularity is so disturbed as hardly to be acknowledged; in
most places we find those stratified bodies broken, dislocated, and
contorted, and this aqueous theory of mineralists has neither the means
for attaining that end, were it required in their theory, nor have they
any such purpose in their theory, were that end attainable by the means
which they employ. Thus blinded by the prejudice of a false analogy,
they do not even endeavour to gratify the human understanding (which
naturally goes in quest of wisdom and design) by forming a hypothetical
or specious theory of the mineral system; and they only amuse themselves
with the supposition of an unknown operation of water for the
explanation of their cabinet specimens, a supposition altogether
ineffectual for the purpose of forming a habitable earth, and a
supposition which is certainly contradicted by every natural appearance.
Thus, in examining geological and mineralogical theories, I am laid
under the disagreeable necessity of pointing out the errors of physical
principles which are assumed, the prejudices of theoretical opinions
which have been received, and the misconceived notions which
philosophers entertain with regard to the system of nature, in which may
be perceived no ineffectual operation, nor any destructive intention,
but the wise and benevolent purpose of preserving the present order of
this world. But, though thus misled with regard to the cause of things,
naturalists are every where making interesting observations in the
mineral kingdom, I shall therefore avail myself of that instructive
information, for the confirmation of my theory.
It may now be proper to consider what must be required, in order to have
a geological and mineral theory established upon scientific principles,
or on such grounds as must give conviction to those who will examine
the subject; for, unless we may clearly see that there are means for
attaining that desirable end, few philosophers will be persuaded to
pursue this branch of knowledge.
A theory is nothing but the generalization of particular facts; and, in
a theory of the earth, those facts must be taken from the observations
of natural history. Nature is considered as absolutely true; no error or
contradiction can be found in nature. For, if such contradiction were
truly found, if the stone, for example, which fell to day were to rise
again to-morrow, there would be an end of natural philosophy, our
principles would fail, and we would no longer investigate the rules of
nature from our observations.
Every natural appearance, therefore, which is explained, _i.e._ which is
made to come into the order of things that happen, must so far confirm
the theory to which it then belongs. But is it necessary, that every
particular appearance, among minerals, should be thus explained in
a general theory of the earth? And, is any appearance, which is not
explained by it, to be considered as sufficient to discredit or confute
a theory which corresponded with every other appearance? Here is a
question which it would require some accuracy to resolve.
If we knew all the powers of nature, and all the different conditions in
which those powers may have their action varied, that is to say, if we
were acquainted with every physical cause, then every natural effect, or
all appearances upon the surface of this earth, might be explained in a
theory that were just. But, seeing that this is far from being the case,
and that there may be many causes of which we are as yet ignorant, as
well as certain conditions in which the known action of powers may be
varied, it must be evident, that a theory of the earth is not to be
confuted by this argument alone, That there are, among natural bodies,
certain appearances which are not explained by the theory. We must
admit, that, not having all the data which natural philosophy requires,
we cannot pretend to explain every thing which appears; and that our
theories, which necessarily are imperfect, are not to be considered as
erroneous when not explaining every thing which is in nature, but only
when they are found contrary to or inconsistent with the laws of nature,
which are known, and with which the case in question may be properly
compared.
But we may have different theories to compare with nature; and, in that
case, the question is not, How far any of those theories should explain
all natural appearances? but, How far any one particular theory might
explain a phenomenon better than another? In this case of comparison, it
will be evident, that if one theory explains natural appearances, then
the opposite to that theory cannot be supposed to explain the same
appearances. If for example, granite, porphyry, or basaltes, should be
found naturally formed by fusion, the formation of those stones could
not be supposed in any case as formed by water, although it could not
be demonstrated that water is incapable of forming those mineral
productions.
In like manner, if those three bodies were proved to have been actually
formed by water alone, then, in other cases where we should have no
proof, they could not be supposed as having been formed by fire or
fusion. It must be evident, that an equal degree of proof of those two
different propositions would leave our judgment in suspence, unless that
proof were perfect, in which case, we would have two different causes
producing similar effects. But, if we shall have a sufficient proof
upon the one side, and only a presumptive proof or probability upon the
other, we must reject that probability or presumption, when opposed by
a proof, although that proof were only an induction by reasoning from
similar effects as following similar causes. _A fortiori_, if there be
on one side a fair induction, without the least suspicion of error,
and on the other nothing but a mere presumption founded upon a distant
analogy, which could not even properly apply, then, the inductive proof
would be as satisfactory as if there had not been any supposition on the
opposite side.
So far as a theory is formed in the generalization of natural
appearances, that theory must be just, although it may not be perfect,
as having comprehended every appearance; that is to say, a theory is
not perfect until it be founded upon every natural appearance; in which
case, those appearances will be explained by the theory. The theory of
gravitation, though no ways doubtful, was not so perfect before the
shape of this globe had been determined by actual measurement, and
before the direction of the plummet had been tried upon Shihallion, as
after those observations had been made. But a theory which should be
merely hypothetical, or founded upon a few appearances, can only be
received as a theory, after it has been found to correspond properly
with nature; it would then be held a proper explanation of those natural
appearances with which it corresponded; and, the more of those phenomena
that were thus explained by the theory, the more would that, which had
been first conjectural, be converted into a theory legitimately founded
upon natural appearances.
Matter of fact is that upon which science proceeds, by generalization,
to form theory, for the purpose of philosophy, or the knowledge of all
natural causes; and it is by the companion of these matters of fact with
any theory, that such a theory will be tried. But, in judging of matter
of fact, let us be cautious of deceiving ourselves, by substituting
speculative reasoning in place of actual events.
Nature, as the subject of our observation, consists of two sorts of
objects; for, things are either active, when we perceive change to take
place in consequence of such action, or they are quiescent, when we
perceive no change to take place. Now, it is evident, that in judging
of the active powers of nature from the quiescent objects of our
information, we are liable to error, in misinterpreting the objects
which we see; we thus form to ourselves false or erroneous opinion
concerning the general laws of action, and the powers of nature. In
comparing, therefore, generalised facts, or theory, with particular
observations, there is required the greatest care, neither, on the one
hand, to strain the appearances, so as to bring in to the theory a fact
belonging to another class of things; nor, on the other, to condemn a
proper theory, merely because that theory has not been extended to the
explanation of every natural appearance.
But, besides the misinterpretation of matters of fact, we are also to
guard against the misrepresentation of natural appearances. Whether
warped by the prejudice of partial and erroneous theory, or deceived by
the inaccuracy of superficial observation, naturalists are apt to see
things in an improper light, and thus to reason from principles which
cannot be admitted, and, which often lead to false conclusions. A
naturalist, for example, comes to examine a cavity in the mines, he
there finds water dropping down all around him, and he sees the cavity
all hung with siliceous crystals; he then concludes, without hesitation,
that here is to be perceived cause and effect, or that he actually sees
the formation of those crystallizations from the operation of water. It
is thus that I have been told by men of great mineral knowledge, men who
must have had the best education upon that subject of mineralogy, and
who have the superintendance of great mineral concerns in Germany, that
they had actually seen nature at work in that operation of forming
rock-crystal;--they saw what I have now described; they could see no
more; but, they saw what had convinced them of that which, there is
every reason to believe, never happened. With regard to my theory,
I wish for the most rigorous examination; and do not ask for any
indulgence whatever, whether with regard to the principles on which the
theory is built, or for the application of the theory to the explanation
of natural appearances. But, let not geologists judge my theory by their
imperfect notions of nature, or by those narrow views which they take of
the present state of things;--let not mineralogists condemn my theory,
for no other reason but because it does not correspond with their false
principles, and those gratuitous suppositions by which they had been
pleased to explain to themselves every thing before. First let them look
into their own theory, and correct that erroneous principle, with regard
to the action of water, or the assumption of unknown causes, upon which
they have reasoned in forming their vague notions of the mineral region,
before they can be properly qualified to examine, impartially, a theory
which employs another principle. Every thing which has come under my
observation shall be, as far as I can, faithfully related; nor shall I
withhold those which neither the present theory, nor any other that I am
acquainted with, can, I think, explain.
Appearances cannot well be described except in relation to some theory
or general arrangement of the subject; because the particular detail,
of every part in a complicated appearance, would be endless and
insignificant. When, however, any question in a theory depends upon the
nature of an appearance, we cannot be too particular in describing that
by which the question is to be decided. But though it be sometimes
proper to be minute in a particular, it is always, and above all things,
necessary to be distinct; and not to confound together things which are
of different natures. For, though it be by finding similarity, in things
which at first sight may seem different, that science is promoted and
philosophy attained, yet, we must have a distinct view of those things
which are to be assimilated; and surely the lowest state of knowledge
in any subject, is the not distinguishing things which, though not to
common observation different, are not truly the same.
To confound, for example one stone with another, because they were both
hard, friable, and heavy, would be to describe, with the superficial
views of vulgar observation; whereas science specifies the weight and
hardness, and thus accurately distinguishes the stone.
Before naturalists had learned to distinguish what they saw, and to
describe, in known terms, those natural appearances, a theorist must
have generalised only from his proper observation. This has been my
case. When I first conceived my theory, few naturalists could write
intelligibly upon the subject; but that is long ago, and things are much
altered since; now there are most enlightened men making observations,
and communicating natural knowledge. I have the satisfaction, almost
every day, to compare the theory, which I had formed from my proper
observations, with the actual state of things in almost every quarter of
the globe.
Whether, therefore, we mean to try a theory by its application to
such phenomena as are well understood, or to learn something from the
application of particular phenomena to a well established theory,
we shall always find it interesting to have appearances described;
particularly such as may be referred to some general rule, as
circumscribing it to certain conditions, or as finding rule in rule,
that is to say, discovering those particular conditions in which the
general laws of action may be affected.
Instead, for example, of the rule which we find in the application of
heat for the fusion and evaporation of mineral substances upon the
surface of this earth, we may find it necessary to consider the effect
which changed circumstances produce in the mineral regions, and occasion
a change of that rule of action which we have learned from experience,
when melting and evaporating those substances in the atmosphere or on
the surface of the earth.
It is in this manner that a theory, which was formed by the
generalization of particular facts, comes to be a source of information,
by explaining to us certain appearances which otherwise we could not
understand. Thus, it was not the appearance of the tides that taught the
theory of gravitation; it was the theory of gravitation that made us
understand the appearance of the tides. In like manner, the law of
gravitation, which was demonstrated from the motion of the moon in her
orbit round this earth, when applied to the paths of comets, explained
that appearance. Our theory, of a central fire, has been formed upon
the consolidation of the strata of this earth; but this theory is to be
applied for the explanation of various different appearances. In this
manner, two different purposes will be served; the trying of the theory
by its application to phenomena; and the explanation of phenomena by the
principles laid open in the theory.
I may repeat it; a theory of the earth must ultimately depend upon
matter of fact or particular observation; but those observations must be
distinct, and those distinguished things must be generalised. We have
just now given for an example, a distinction among stones, in knowing
them by their sensible qualities. But, besides distinguishing those
objects, we are also to inquire into the origin and cause of those
things which are distinguished. Here, again, we take into our aid the
chemical as well as the mechanical properties of these several things;
and hence learn to know on what their natural form and constitution may
depend. Having thus attained the natural philosophy of stones, we next
inquire into the place and application of those things in nature; and
in this manner we acquire some knowledge with regard to the natural
constitution of this earth. We find this earth composed of known things;
it is therefore the operations, required in these compositions, which
form the natural philosophy of this earth, considered as a body of solid
land. But, the solid land is only one part of the globe; therefore,
the philosophy of the globe proceeds still farther by knowing the
constitution of this planetary body, as consisting of different parts
united for a purpose, which is that of a world.
The general theory of this earth as a world, will thus appear to be a
complex thing, which however founded upon simple principles, contains
many subjects of discussion, and requires attention to a variety of
particulars. For, not only the great features of this earth are to be
explained by the theory, but also the most minute appearance, such as
are to be found, even with microscopic observation, in every particular
part.
Thus the nature, constitution, and cause of every particular appearance
in the construction of this earth, are to be investigated in a
geological theory, as well as that general constitution of the world in
which all the particular parts are to be employed for a purpose.
If the subject here examined shall be found properly explained, there
will remain little doubt with regard to the justness of the theory,
which will then be applicable to other appearances that may occur;
although every appearance is not to be explained, in a manner equally
satisfactory, by any theory which is not perfect.
The first subject to be examined is the modern theory of primitive
mountains. I have written several chapters upon that subject, having
successively acquired more light in this interesting part of the theory,
by observations of my own in several places of this country, as well as
from the natural history of other countries. I shall give these nearly
in the order in which they occurred, or had been written.
CHAP. IV.
The Supposition of Primitive Mountains refuted.
In the theory now given, the earth has been represented as a composition
of different materials, which had existed in another form, and as the
effect of natural operations; therefore, however various may be found
the structure of our earth, and however dissimilar some parts of
its composition may be in comparison with others, no part should be
considered as original, in relation to the globe, or as primitive, in
relation to second causes, _i.e._ physical operations by which those
parts should have been formed. But it is pretended by naturalists, that
there are certain primitive mountains in the earth, bodies which have
had another origin than that of the general strata of the globe and
subsequent masses; an origin, therefore, which cannot be considered as
having been produced from natural operations, or as effected in the
course of known causes. Now, if it can be made to appear, that there is
no solid ground for this distinction; and if it can be shown, that there
is truly no mineral body in this earth which may not have been produced
by operations natural to the globe, we should thus procure a certain
confirmation of the doctrine. This also will be the more interesting,
in being deduced from a part of natural appearances, which seemed to be
inconsistent with the theory.
Certain masses or mountains of granite, are the only bodies of this
earth which have apparently a certain pretension to this species
of originality. These, therefore, must be now the subject of our
examination.
Granite, considered by itself, does not appear to have any claim to
originality in its nature. It is composed of bodies which are capable of
being analyzed; and these are then found to be compositions of different
substances, which are also sometimes variously proportioned. The
feldspar and the mica, for example, as well as the schorl, are found
variously coloured in different granites, and coloured in various
proportions. Besides the variety in the composition, or chemical mixture
of the different bodies which compose granite, this rock admits of a
great diversity, from the variety of its mechanical mixture, or from
the different species of bodies which are its constituent parts. M. de
Saussure, who has examined this subject perhaps more than any other
person, and who has had the very best opportunities for this purpose,
says, that this composition may be found in all the different
combinations which may be produced by every possible composition of 7
or 8 different kinds of stone, (page 108, Voyage dans les Alpes, etc.).
Neither does this fill up the measure of its variety; for, another
source of change is found in the grain of this rock stone; I have a
specimen of this variety from the size almost of sand to that of some
inches.
Were granite, therefore, to be supposed as in the original state of its
creation, nature would be considered as having operated in an indefinite
diversity of ways, without that order and wisdom which we find in all
her works; for here would be change without a principle, and variety
without a purpose. There is no reason, however, to suppose granite
original, more than any other composite rock, although we may be
ignorant of the particular process in which it is formed, and although,
comparatively in relation to certain other rocks, granite, or certain
masses of this composition, may be found of a more ancient date.
If granite be truly stratified, and those strata connected with the
other strata of the earth, it can have no claim to originality; and
the idea of primitive mountains, of late so much employed by natural
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