Scientific American Supplement, No. 514, November 7, 1885
by
Various
Part 2 out of 2
21| " |1872|Taylor | " | " | " | "
| | | | | | |
22| " |1872|Waterbury | " | " | " | "
| | | | | | |
23| " |1872|Sulphate | " |Pennsyl- | " |J.A. Partridge
| | | of iron | | vania Ave| |
| | | | | | |
24| " |1872|Samuel | " |F. Street | " | "
| | | | | | |
25| " |1872|Samuel | " |16th St. | " | "
| | | | | | |
26|Norvolk, Va.| - |Red lead |Pine and |Teredo | " |P.C. Asserson
| | | | oak | | |
| | | | | | |
27| " | - |White zinc | " | " | " | "
| | | | | | |
28| " | - |Tar and | " | " | " | "
| | | plaster | | | |
| | | | | | |
29| " | - |Kerosene | " | " | " | "
| | | | | | |
30| " | - |Rosin and | " | " | " | "
| | | tallow | | | |
| | | | | | |
31| " | - |Fish oil & | " | " | " | "
| | | tallow | | | |
| | | | | | |
32| " | - |Verdigris | " | " | " | "
| | | | | | |
33| " | - |Bark on | " | " |Good for | "
| | | pile | | | 5 years |
| | | | | | |
34| " | - |Carbolic | " | " |Failure | "
| | | acid | | | |
| | | | | | |
35| " | - |Tar and | " | " | " | "
| | | cement | | | |
| | | | | | |
36| " | - |Davis' | " | " | " | "
| | | compound | | | |
| | | | | | |
37| " | - |Carbolized | " | " | " | "
| | | paper | | | |
| | | | | | |
38| " | - |Paint | " | " | " | "
| | | | | | |
39| " | - |Thilmany | " | " | " | "
| | | | | | |
40| " | - |Vulcanized | " | " | " | "
| | | fiber | | | |
| | | | | | |
41| " | - |Charring | " | " |Good for | "
| | | | | | 9 years |
| | | | | | |
42|New Orleans |1872| " |Piles | " |Failure |J.W. Putnam
| & Mobile | | | | | |
| R.R. | | | | | |
| | | | | | |
43| " |1872| " & | " | " |Temporary| "
| | | oiling | | | prot'n |
| | | | | | |
44|Galveston & |1870|Charring | " | " | " | "
| Houston |1874| | | | |
| R.R. | | | | | |
--+------------+----+-----------+---------+----------+---------+---------------
COMMENTS ON MISCELLANEOUS EXPERIMENTS.
Experiments Nos. 1, 2, and 3 relate to the Earle process, from which
great results were expected from 1839 to 1844. It consisted in immersing
timber, rope, canvas, etc., in a hot solution of one pound of sulphate
of copper and three pounds of sulphate of iron mixed in twenty gallons
of water. It was first tested on some hemlock paving blocks on Chestnut
Street, Philadelphia, and for a time seemed to promise good results.
Experiments with prepared rope, exposed in a fungus pit, by Mr. James
Archbald, Chief Engineer of the Delaware and Hudson Canal, seemed also
favorable.
The process was, therefore, thoroughly tried at the Watervliet Arsenal,
where it was applied to some 63,000 cubic ft. of timber, at a cost of
about seven cents per cubic foot. The timber was used for various
ordnance purposes, and while it was found to have its life extended, as
would naturally be expected from the known character of the antiseptics
used, its strength was so far impaired, and it checked and warped so
badly, that the process was abandoned in 1844.
The committee is indebted to General S.V. Benet, Chief of Ordnance, for
a full copy of the reports upon these experiments.
Experiments Nos. 4 and 7 represent the lime process, which has been
applied to a considerable extent in France. The fact that platforms and
boxes used for mixing lime mortar seem to resist decay has repeatedly
suggested the use of lime for preserving timber. In 1840 Mr. W.R.
Huffnagle, Engineer of the Philadelphia and Columbia Railroad, laid a
portion of its track on white pine sills, which had been soaked for
three months in a vat of lime-water as strong as could be maintained.
Similar experiments were tried on the Baltimore and Ohio in 1850. The
result was not satisfactory, as might be expected from the fact that
lime is a comparatively weak antiseptic (52.5 by atomic weight, while
creosote is 216), and from the extreme tediousness of three months'
soaking.
Experiments Nos. 5 and 8 were tried with sulphate of iron, sometimes
known as payenizing, and the particulars of the former have been
furnished by Mr. I. Hinckley, President of the Philadelphia, Wilmington,
and Baltimore Railroad, to whom your committee is much indebted for a
large mass of information on the subject of timber preservation.
Mr. Hinckley has had longer and more varied experience on this subject
than any other person in this country. Beginning with sulphate of copper
in 1846, following with chloride of mercury in 1847, and chloride of
zinc in 1852, going back to chloride of mercury, and again to chloride
of zinc, using the latter until 1865, then using creosote to protect the
piles against the _teredo_ at Taunton Great River (experiment No. 2.
creosoting), he has had millions of feet of timber and lumber prepared
by the various processes, and has kindly placed at our disposal many
original reports in manuscript and pamphlets which are now very rare.
Experiment No. 6 was made by Mr. Ashbel Welch, former President of this
Society, and consisted in boring hemlock track sills 6 x 12 with a 1-1/8
inch auger-hole 10 inches deep every 15 inches. These were filled with
common salt and plugged up, as is not infrequently done in
ship-building, but while the life of the timber was somewhat lengthened,
it was concluded that the process did not pay.
Salt has been experimented with numberless times. It is cheap, but is a
comparatively weak antiseptic, its atomic weight being 58.8 in the
hydrogen scale, as against 135.5 for chloride of mercury.
Experiment No. 9 is included in order to notice the well-known and most
ancient process of charring the outside of timber. In this particular
case, the fence posts after charring were dipped for about three feet
into a hot mixture of raw linseed oil and pulverized charcoal, which
probably acted by closing the sap cells against the intrusion of
moisture, which, as is well known, much hastens decay. The posts, which
had been set butt-end upward, were mostly sound in 1879, after 24 years'
exposure.
Experiments Nos. 41, 42, 43, and 44 did not, however, result as well,
and numberless failures throughout the country attest that charring is
uncertain and disappointing in its results.
Much ingenuity has been wasted in devising and patenting machinery for
charring wood on a large scale to preserve it against decay. The
process, however, is so tedious in comparison with the benefits which it
confers, and the charred surface is so objectionable for many uses, that
nothing is to be expected from the process upon a large commercial
scale.
In 1857-58 Mr. H.K. Nichols tried sundry experiments (No. 10), at
Pottsville, Pa., upon timber which he endeavored to impregnate with
pyrolignite of iron by means of capillary action. Similar experiments
had previously been thoroughly tried in France by Dr. Boucherie, but the
result has not been found satisfactory.
In 1858 the Erie Railway purchased the right of using the Nichols
patent, and erected machinery at its Owego Bridge shop for boring a 2
inch hole longitudinally through the center of bridge timbers. This
continued till 1870, when the works were burned, and in rebuilding them
the boring machinery was not replaced. The longitudinal hole allowed a
portion of the sap to evaporate without checking the outside of the
timber, and undoubtedly lengthened its life. It is believed there are
yet (1885) some sticks of timber in the bridges of the road that were so
prepared in 1868 or 1869.
In 1867 Mr. W.H. Smith patented a method of preserving timber, by
incasing it in vitrified earthenware pipes, and filling the space
between the timber and the pipe with a grouting of hydraulic cement.
This was applied to the railroad bridge connecting the mainland with
Galveston Island (experiment No. 12), and so well did it seem to succeed
at first that it was proposed to extend the process to railroad
trestlework, to fencing, to supports for houses, and to telegraph poles.
But after a while the earthenware pipes were displaced and broken, the
process was given up, and Galveston bridge is now creosoted.
In 1868 Mr. S. Beer patented a process for preserving wood by simply
washing out the sap from its cells. Having ascertained that borax is a
solvent for sap, he prepared a number of specimens by boiling them in a
solution of borax. For small specimens, this answered well, and a
signboard treated in that way (experiment No. 13) was preserved a long
time; but when applied to large timber, the process was found very
tedious and slow, and no headway has been made in introducing it.
Experiment No. 14 was brought about by accident. Some years age it was
discovered that there was a strip of road in the track of the Union
Pacific Railroad, in Wyoming Territory, about ten miles in length, where
the ties do not decay at all. The Chief Engineer, Mr. Blinkinsderfer,
kindly took up a cotton wood tie in 1882, which had been laid in 1868,
and sent a, piece of it to the committee. It is as sound and a good deal
harder than when first laid, 14 years before, while on some other parts
of the road cottonwood ties perish in two or five years.
The character of the soil where these results have been observed is
light and soapy, and Mr. E. Dickinson, Superintendent of the Laramie
Division, furnishes the following analysis:
Sodium chloride 10.64
Potassium 4.70
Magnesium sulphate 1.70
Silica 0.09
Alumina 1.94
Ferric oxide 5.84
Calcium carbonate 22.33
Magnesium 3.39
Organic matter 4.20
Insoluble matter 941.47
Loss in analysis 4.00
Traces of phosphorous acid and ammonia.
The following remarks made by the chemists who made the analysis may be
of interest:
"The decay of wood arises from the presence in the wood of substances
which are foreign to the woody fiber, but are present in the juices of
the wood while growing, and consist of albuminous matter, which, when
beginning to decay, causes also the destruction of the other
constituents of the wood."
"One of the means adopted to prevent the destruction of wood by decay is
by the chemical alteration of the constituents of the sap."
"This is brought about by impregnating the wood with some substance
which either enters into combination with the constitutents of the sap
or so alters their properties as to prevent the setting up of
decomposition."
"The analysis of this soil shows that it contains large quantities of
the substances (sodium, potassium chloride, calcium, and iron) most used
in the different processes of preserving or kyanizing wood. It also
contains much inorganic matter, which also acts as a preserving agent."
Some of the ties so preserved have been transferred to other portions of
the track, and some of the soil has also been transported to other
localities, so that it is hoped that in the discussion that may be
expected to follow this report, some further light will be thrown on the
subject by an account of the results of these experiments.
Experiments Nos. 15, 16, 17, and 18 are most instructive, and convey a
useful lesson.
In 1865 Mr. B.S. Foreman patented the application of a dry powder for
preserving wood, which was composed of certain proportions of salt,
arsenic, and corrosive sublimate. This action was based upon an
experience which he had had when, as a working mechanic of Ellisburg,
Jefferson County, N.Y., in 1838, he had preserved a water-wheel shaft by
inserting such a compound in powder in the body of the wood, and
ascertained that it was still sound some 14 years later.
His theory of the action of his compound upon timber was briefly this:
"That all wood before it can decay must ferment; that fermentation
cannot exist without heat and moisture; that the chemical property or
nature of his compound, when inserted dry into wood, is to attract
moisture, and this moisture, aided by fermentation, liquefies the
compound; that capillary attraction must inevitably convey it through
the sap ducts and medullary rays to every fiber of the stick.... Were
these crystallizations salt alone, they would soon dissolve, but the
arsenic and corrosive sublimate have rendered them insoluble; hence they
remain intact while any fiber of the wood is left."
"The antiseptic qualities of arsenic are also well known, and have been
known for centuries. Chemical analysis of the _mummies of Egypt_ to-day
shows the presence of arsenic in large quantities in every portion of
their substance. Whatever other ingredients may have entered into the
compound that has been so potent in preserving from decay the bodies of
the old kings of Egypt, and even the linen vestments of their tombs,
arsenic was most certainly one."
The mode of application used by Mr. Foreman was to bore holes two inches
in diameter three-fourths of the way through sticks of square timber,
four feet apart, to fill them with the dry powder, and to plug them up
with a bung. For railroad ties he bored two holes two inches in
diameter, six inches inside of the rails, and filled and plugged them.
Fresh cut lumber and shingles were prepared by piling layers upon each
other with the dry powder sprinkled between in the ratio of twenty
pounds to the thousand feet of lumber. This was allowed to remain at a
temperature of at least 458 deg. F. until fermentation took place, when the
lumber was considered fully "foremanized."
The process was first applied to the timber and lumber for a steamboat,
and in 1879 the result was reported to be favorable. It was then applied
to some ties on the Illinois Central Railroad, where it did not succeed,
and to some on the Chicago and Northwestern, where they seem to have
been lost sight of, being few in number, so that your committee has not
been able to learn the result.
Great expectations were, however, entertained, and a conditional sale
was made to various parties of the right of using the process, notably,
it is said, to the Memphis and Charleston Railroad for $50,000; and some
ten miles of ties were prepared on that road, when the poisonous nature
of the ingredients used brought about disaster.
Some shingles were prepared for a railroad freight house at East St.
Louis, but all the carpenters who put them on were taken very ill, and
one of them died.
The arsenic and corrosive sublimate effloresced from the ties along the
Memphis and Charleston Railroad. Cattle came and licked them for the
sake of the salt, and they died, so that the track for ten miles was
strewed with dead cattle. The farmers rose up in arms, and made the
railroad take up and burn the ties. The company promoting foremanizing
was sued and cast in heavy damages, and it went out of business.
In 1870 Mr. A.B. Tripler patented a mixture of arsenic and salt, and the
succeeding year a specimen of wood prepared under that patent was
submitted to the Board of Public Works of Washington, D.C., and examined
by its chemist, Mr. W.C. Tilden (experiment 19). He found the
impregnation uneven, and the absorptive power high, but he did not find
any arsenic, though its use was claimed.
The Samuel process (experiment 20) consisted in the injection, first, of
a solution of sulphate of iron, and afterward of common burnt lime. Mr.
Tilden reported the wood to be brittle, and the water used to test the
absorptive power to have been filled with threads of fungi in
forty-eight hours.
The Taylor process (experiment No. 21) used a solution of sulphide of
calcium in pyroligneous acid. It was condemned by Mr. Tilden.
The Waterbury process (experiment 22) consisted in forcing in a solution
of common salt, followed by dead oil or creosote. It was also condemned
by Mr. Tilden.
The examinations of Mr. Tilden extended to some fourteen different
processes, most of which have already been noticed in this report, and
their practical results given.
The Board of Public Works, however, laid down a considerable amount of
prepared wood pavement in Washington, all of which is understood to have
proved a dismal failure. After a good deal of inquiry, your committee
has been enabled to obtain information of the results of three of these
experiments.
The pine paving blocks upon Pennsylvania Avenue (experiment 23) were
first kiln-dried, and then immersed in a hot solution of sulphate of
iron.
The spruce blocks on E Street (experiment 24) were treated with chloride
of zinc, or, in other words, burnettized; but the mode of application is
not stated.
The pine blocks upon Sixteenth Street (experiment 25) were treated with
the residual products of petroleum distillation. It is stated that this
was the only process in which pressure was used.
In from three and a half to four and a half years the blocks were badly
decayed, and large portions of the streets were almost impassable, while
other streets paved in the same year with untreated woods remained in
fair condition.
It has been stated to your committee that this result, which did much
toward bringing all wood preserving processes into contempt, was chiefly
owing to the very dishonest way in which the preparation was done; that
in fact there was a combination between the officials and the
contractors by which the latter were chiefly interested "how not to do
it," and that the above results, therefore, prove very little on the
subject of wood preservation.
Through the kindness of the United States Navy Department your committee
is enabled to give the results of a series of experiments (Nos. 26 to 41
inclusive) which have been carried on at the Norfolk, Va., Navy Yard,
for a series of years, by Mr. P.C. Asserson, Civil Engineer, U.S.N., to
test the effect of various substances as a protection against the
_Teredo navalis_. It will be noticed that the application of two coats
of white zinc paint, of two coats of red lead, of coal tar and plaster
of Paris mixed, of kerosene oil, of rosin and tallow mixed, of fish oil
and tallow mixed and put on hot, of verdigris, of carbolic acid, of coal
tar and hydraulic cement, of Davis' patent insulating compound, of
compressed carbolized paper, of anti-fouling paint, of the Thilmany
process, and of "vulcanized fiber," have proved failures.
The only favorable results have been that oak piles cut in the month of
January and driven with the bark on have resisted four or five years, or
till the bark chafed or rubbed off, and that cypress piles, well
charred, have resisted for nine years.
This merely confirms the general conclusion which has been stated under
the head of creosoting, that nothing but the impregnation with creosote,
and plenty of it, is an effectual protection against the _teredo_.
Numberless experiments have been tried abroad and in this country, and
always with the same result.
There are quite a number of other experiments which your committee has
learned about which are here passed in silence. The accounts of them are
vague, or the promised results of such slight importance as not to
warrant cumbering with them this already too voluminous report.
The committee also forbears from discussing the merits of the many
patents which have been taken out for wood preservation. It had prepared
a list of them, and investigated the probable success of many of them,
but has concluded that it is better to confine itself to the results of
actual tests, and to stick to ascertained facts.
Neither does the committee feel called upon to point out the great
importance of the subject, and the economical advantages which will
result from the artificial preparation of wood as its price advances.
They hope, however, that the members of this Society, in discussing this
report, will dwell upon this point.
We shall instead give as briefly as possible the general conclusions
which we have reached as the result of our protracted investigation.
DECAY OF TIMBER.
Pure woody fiber is said by chemists to be composed of 52.4 parts of
carbon, 41.9 parts of oxygen, and 5.7 parts of hydrogen, and to be the
same in all the different varieties. If it can be entirely deprived of
the sap and of moisture, it undergoes change very slowly, if at all.
Decay originates with the sap. This varies from 35 to 55 per cent. of
the whole, when the tree is felled, and contains a great many
substances, such as albuminous matter, sugar, starch, resin, etc., etc.,
with a large portion of water.
Woody fiber alone will not decay, but when associated with the sap,
fermentation takes place in the latter (with such energy as may depend
upon its constituent elements), which acts upon the woody fiber, and
produces decay. In order that this may take place, it is believed that
there must be a concurrence of four separate conditions:
1st. The wood must contain the elements or germs of fermentation when
exposed to air and water.
2d. There must be water or moisture to promote the fermentation.
3d. There must be air present to oxidize the resulting products.
4th. The temperature must be approximately between 50 deg. and 100 deg. F. Below
32 deg. F. and above 150 deg. F., no decay occurs.
When, therefore, wood is exposed to the weather (air, moisture, and
ordinary temperatures), fermentation and decay will take place, unless
the germs can be removed or rendered inoperative.
Experience has proved that the coagulation of the sap retards, but does
not prevent, the decay of wood permanently.[1] It is therefore necessary
to poison the germs of decay which may exist, or may subsequently enter
the wood, or to prevent their intrusion, and this is the office
performed by the various antiseptics.
[Footnote 1: Angus Smith, 1869, "Disinfectants." S.B. Boulton, 1884,
Institution Civil Engineers, "On the Antiseptic Treatment of Timber."]
We need not here discuss the mooted question between chemists, whether
fermentation and decay result from slow combustion (eremacausis) or from
the presence of living organisms (bacteria, etc.); but having in the
preceding pages detailed the results of the application of various
antiseptics, we may now indicate under what circumstances they can
economically be applied.
_(To be continued)_.
* * * * *
THE SPAN OF CABIN JOHN BRIDGE.
_To the Editor of the Scientific American Supplement:_
Your issue of 17th October contains the fifth or sixth imprint of Mr. B.
Baker's, C.E., recent address at the British Association of Aberdeen
which has come into my hands.
In speaking of stone bridges, he alludes to the bridge over the Adda as
500 years old. It was never more than 39 years old as stated in the same
address, and he belittles the American Cabin John Bridge by making its
span _"after all only 215 ft."_ As the builder of this greatest American
stone arch, I regret that on so important and public an occasion the
writer was not accurate.
The clear span of Cabin John Bridge is 220 ft. The difference is not
great, but in the length of a bridge span it is the last foot that
counts, as in an international yacht race to be beaten by one minute is
to fail to capture the cup.
M.C. MEIGS.
Washington, D.C., Oct. 16, 1885.
* * * * *
THE GERMAN CORVETTE AUGUSTA.
On the 3d of June of this year, the German cruising corvette Augusta
left the island of Perrin, in the Straits of Bab el Mandeb, for
Australia; and as nothing has been heard of her since that day, the
report that she was destroyed in the typhoon on June 3 is probably
correct. The vessel left Kiel on April 28, with the crews for the
cruisers of the Australian squadron; 283 men were on board, including
the commander, Corvette Captain Von Gloeden. There is still a
possibility that the Augusta was dismasted, and is drifting somewhere in
the Indian Ocean, or has stranded on an island; but this is not very
probable, as the Augusta was not well adapted to weather a typhoon.
During her cruise of 1876 to 1878, all the upper masts, spars, etc, had
to be removed, that she might be better adapted to weather a cyclone or
like storm. If the Augusta had not met with an accident, she would have
arrived at Port Albany in Australia by the 30th of June or beginning of
July. She was due June 17.
The Augusta was built at Armands' ship yards at Bordeaux, and was bought
in 1864 by Prussia. She was a screw steamer with ship's rigging, 2371/2
feet long, 351/2 feet beam, 16 feet draught, and 1,543 tons burden. Her
engines had 400 horse-power, and her armament consisted of 14 pieces.
[Illustration: THE GERMAN CORVETTE AUGUSTA.]
During the Franco-German war of 1870-71, she was commanded by Captain
Weikhmann, and captured numerous vessels on the French coast. January 4,
1871, she captured the French brig St. Marc, in the mouth of the
Gironde; the brig was sailing from Dunkirken to Bordeaux with flour and
bread for the Third French Division. The Augusta then captured the
Pierre Adolph, loaded with wheat, which was being carried from Havre to
Bordeaux. Then the French transport steamer Max was captured and burned.
The French men of war finally forced the Augusta to retreat into the
Spanish port of Vigo, from which she sailed Jan. 28, and arrived March
28 at Kiel, with the captured brig St. Marc in tow.--_Illustrirte
Zeitung_.
* * * * *
IMPROVEMENT IN METAL WHEELS.
In the Inventions Exhibitions may be seen a good form of metal wheel,
the invention of Mr. H.J. Barrett, of Hull, Eng., and which we
illustrate.
[Illustration: FIG. 1. FIG. 2. FIG. 3.]
Fig. 1 is a perspective view of the wheel, Fig. 2 a transverse section,
and Fig. 3 a longitudinal section of the boss. These wheels are made in
two classes, A and B. Our engraving illustrates a wheel of the former
class, these wheels being designed for use on rough and uneven roads,
and when very great jolting strains may be met with, being stronger than
those of class B design. The wheels are made with mild steel spokes,
which are secured by metal straps in the recesses cut in the annular
flanges on the boss, and by a taper bolt or rivet through the tire and
rim. These spokes can be easily taken out and renewed when necessary by
any unskilled person in a few minutes. The spokes being twisted midway
of their length give greater strength to the wheel and power to resist
side strains in pulling out of deep ruts or holes, without increasing
the weight. The bosses and straps are made of malleable iron, in which
the metal bushes are secured by means of a key with a washer screwed up
on the front end. They are also fitted with steel oil caps to the end of
the bushes, which are provided with a small set screw, so that the cap
need not be taken off when it is necessary to lubricate the wheel, as by
simply taking out the set screw oil may be poured through the hole into
the cap. The set screw also forms a fulcrum for a key, so that the cap
can be taken off or put on when required, as well as a means of
preventing the cap being lost by shaking loose on rough roads. In all
hot and dry climates, the continued shrinking of wood wheels and
loosening of the tires is a constant source of expense and
inconvenience. This wheel having a tire and rim entirely of metal does
away with the difficulty, as the expansion and contraction are equal,
consequently the tires need only be removed when worn out, and others
can be supplied, drilled complete, ready for putting on, which can be
done by any unskilled person. The wheels of class B design are the same
in principle of construction as those of class A, but they have cast
metal bosses or naves, without loose bushes, and are suitable for
general work and ordinary roads where the strains are not so severe. The
bosses or naves are readily removed in case of breakage, and they can be
fitted with steel oil caps for lubricating.--_Iron_.
* * * * *
APPARATUS FOR THE PRODUCTION OF WATER GAS.
The apparatus shown in the accompanying engraving is designed for the
manufacture of water gas for heating purposes, and is described in a
communication, by Mr. W.A. Goodyear, to the American Institute of Mining
Engineers.
The generator, A, is lined with refractory bricks and is filled with
fuel, which may be coal, coke, or any suitable carbonaceous material. B
and B' are two series of regenerating chambers lined with refractory
brick, and, besides, filled with refractory bricks piled up as shown in
the figure. The partitions, C and C', are likewise of refractory brick,
and are rendered as air-proof as possible. Apertures, D and D', are
formed alternately at the base of one partition and the top of the
adjacent one, in order to oblige the gases that traverse the series of
chambers to descend in one of them and to rise in the following,
whatever be the number of chambers in use.
The two flues, E and E', lead from the bottom of the two nearest
regenerator on each side to the bottom of the generator A, and serve to
bring the current of air or steam into contact with the fuel. Valves, F
and F', placed in these flues, permit of regulating the current in the
two directions. Pipes, M and M', provided with valves, G and G', put the
upper part of the generator in communication with the contiguous
chambers, T and T'. Other pipes, N and N', with valves, H and H', permit
of the introduction of a current of air from the outside into the
chambers, T and T'. The pipes, O and O', and the valves, I and I',
connected with a blower, serve for the same purpose. The pipes, P and
P', and their valves, J and J', lead a current of steam. The conduits, Q
and Q', and their valves, K and K', direct the gases toward the
purifiers and the gasometer. Finally, the pipes, R and R', provided with
valves, L and L', are connected with a chimney.
The generator, A, is provided at its upper part with a feed hopper. The
doors, S and S', of the ash box close the apertures through which the
ashes are removed.
When it is desired to use the apparatus, the pipes, P, Q, and R, are
closed by means of their valves, J, K, and L, and the valve, I, of the
pipe, O, is opened. The pipes, M and N, are likewise closed, while the
flue, E, is opened. On the other side of the generator the reverse order
is followed, that is to say, the flue, E', is closed, the pipes, M' and
N', are opened, the pipes, O', P', and Q', are closed, and R' is opened.
A current of air is introduced through the pipe, O, and this traverses
the regenerators, B, enters the chamber, T, and the generator, A,
through the flue, E. As this air rises through the mass of incandescent
fuel, its oxygen combines with an atom of carbon and forms carbonic
oxide. This gas that is disengaged from the upper part of the fuel
consists chiefly of nitrogen and carbonic oxide, mixed with volatile
hydrocarburets derived from the fuel used. This gas, through the action
of the air upon the fuel, is called "air gas," in order to distinguish
it from the "water gas" formed in the second period of the process.
The air gas, on issuing from the generator through the pipe, M', in
order to pass into the chamber, F', meets in the latter a second current
of air coming in through the pipe, N', and which burns it and produces,
in doing so, considerable heat. The strongly heated gases resulting from
the combustion traverse the regenerators, B', and give up to the bricks
therein the greater part of their heat, and finally make their exit,
relatively cool, through the pipe, R', which leads them to the chimney.
When the operation has been continued for a sufficient length of time to
give the refractory bricks in the chamber, B', next the regenerator a
high temperature, the valve, I, is closed, thus shutting off the
entrance of air through the pipe, Q. The valve, F, of the flue, E, is
also closed, and that of the pipe, M, is opened. The valves, G', H', L',
of the pipes, M', N', R', are closed, and that, F', of the flue, E', is
opened. The valve, J', of the pipe, P', is then opened, and a jet of
steam is introduced through the latter.
The steam becomes superheated in traversing the regenerators, B', and in
this state enters the bottom of the generator through the flue, E'. In
passing into the incandescent fuel that fills the generator, the steam
is decomposed, and there forms carbonic oxide, while hydrogen is
liberated. The mixture of these two gases with the hydrocarburets
furnished by the fuel constitutes water gas. This gas on making its exit
from the generator through the pipe, M', passes through the chambers, B,
and abandons therein the greater part of its heat, and enters the pipe,
R, whence it passes through Q into the purifiers, and then into the
gasometer.
As the production of water gas implies the absorption of a large
quantity of sensible heat, it is accompanied with a rapid fall of
temperature in the chambers, B', and eventually also in the generator,
A, while at the same time the chambers, B, are but moderately heated by
the sensible heat of the current of gas produced. When this cooling has
continued so long that the temperature in the generator, A, is no longer
high enough to allow the fuel to decompose the steam with ease, the
valve, J', of the pipe, P', that leads the steam is closed, as is also
the valve, K, of the pipe, Q, while the valves, L and H, of the pipes, R
and N, are opened. After this the valve, I', is opened, and a current of
air is let in through the pipe, O'. This air, upon traversing the
chambers, B' and T', is raised to a high temperature through the heat
remaining in these chambers, and then enters at the bottom of the
generator, through the flue, E'. The air gas that now makes its exit
from the pipe, M, in the chamber, T, meets another current of air coming
from the pipe, N, and is thus burned. The products resulting from such
combustion pass into the chambers, B, and then into the chimney, through
the pipe, R. The temperature then rapidly lowers in the chambers, B',
and rises no less rapidly in the generator, A, while the chambers, B,
are soon heated to the same temperature that first existed in the
chambers, B'. As soon as the desired temperature is obtained in the
generator, A, and the chambers, B, the air is shut off by closing the
valve, I', of the pipe, O'; the valve, F', of the flue, E', is also
closed, the valves, G' and K', of the pipes, M' and Q', are opened, the
valves, G, H, and L, of the pipes, M, N, and R, are closed, and the
valve, F, of the flue, E, and the valve, J, of the pipe, P, are opened.
A current of steam enters the apparatus through the pipe, P, traverses
the chambers, B, and enters the generator through the flue, E. The gas
produced makes its exit from the generator, passes through the pipe, M',
and the chambers, T' and B', and the pipe, R, and enters the gasometer
through the pipe, Q'.
[Illustration: WATER-GAS APPARATUS.]
When the chamber, B, and the generator, A, are again in so cool a state
that the fuel no longer decomposes the steam easily, the valves are so
maneuvered as to stop the entrance of the latter, and to send a current
of air into the apparatus in the same direction that the steam had just
been taking. The temperature thereupon quickly rises in the generator,
A, while, at the same time, the combustion of the air gas produced soon
reheats the chambers, B'. The cooled products of combustion go, as
before, to the chimney. The position of the valves is then changed again
so as to send a current of steam into the apparatus in a direction
contrary to that which the air took in the last place, and the water gas
obtained again is sent to the gasometer.
As will be seen, the process is entirely continuous, each current of air
following the same direction in the apparatus (from left to right, or
right to left) that the current of steam did which preceded it, while
each current of steam follows a direction opposite that of the current
of air which preceded it.
The inventor estimates that the cost of the coal necessary for his
process will not exceed a tenth of a cent per cubic foot of gas.
One important advantage of the apparatus is that it can be made of any
dimensions. Instead of giving the generator the limited size and form
shown in the engraving, with doors at the bottom for the removal of the
ashes by hand from time to time, it may be constructed after the general
model of the shaft of blast furnaces, with a hearth at the base. Upon
adding to the fuel a small quantity of flux, all the mineral parts
thereof can be melted into a liquid slag, which may be carried off just
like that of blast furnaces. There is no difficulty in constructing
regenerators of refractory bricks of sufficient capacity, however large
the generators be; and a single apparatus might, if need be, convert one
thousand tons of anthracite per day into more than five million cubic
feet of gas.
* * * * *
LIGHTING AND VENTILATING BY GAS.
[Footnote: A paper read before the Gas Institute, Manchester, June,
1885.]
By WILLIAM SUGG, of London.
Ever since the introduction of electric lighting, the public have been
assured, by those interested in the different kinds of lamps--arc, glow
or otherwise--that henceforth, by means of such lamps, rooms are to be
lighted without heat or baneful products such as they assert attend the
use of gas, lamps, or candles. But I think it must not be implied, from
what any one has said in favor of the electric light as a means of
lighting our dwellings, that gas is unsuitable for the purpose, or that
the glow lamp is a perfect substitute for gas, or that there is a very
large difference throughout the year on the points of health,
convenience, or comfort, or that the balance in favor rests with
electric light upon all or any of these points. The fact is, the glow
lamp is only one more means (not without certain disadvantages) of
producing light added to those which already exist, and of which the
public have the choice. Now, looking to best means of lighting rooms,
and particularly the principal rooms of a small dwelling-house, I beg to
say that the arguments which can be adduced in favor of gas lighting in
preference to any other means greatly preponderate, and that it can be
substantiated that, light for light, under the heads of convenience,
health, comfort, reliability, readiness, and cheapness, gas is superior
to all.
As a scientific means for the purposes mentioned, gas is comparatively
untried. This assertion may sound somewhat astounding; but I think it is
a true one. More than that, even in the crude and unscientific way in
which it has most frequently been used up to the present, it has been
far from unsuccessful in comparison with electricity or other means of
lighting; and in the future it will prove the best and cheapest
practical means, although, for effect, glow lamps may be used in
palatial dwellings in conjunction with it.
It must be remembered that, in laying down a system of artificial
lighting, we have to imitate, as well as we can, that most beautiful and
perfect natural light which, without our aid, and without even a thought
from us, shines regularly every day upon all, in such an immense volume,
so perfectly diffused, and in such wonderful chemical combination, that
it may safely be said that not one atom of the whole economy of Nature
is unaffected by it, and that we and all the animal kingdom, in common
with trees and plants, derive health and vigor therefrom. This glorious
natural light leaves our best gas, electricity, oil lamp, and all our
multiplicity of candles, immeasurably behind. But although we cannot
hope to equal, in all its beneficent results, the effects of daylight,
or to perfectly replace it, we can more perfectly make the lighting of
our homes comfortable (and as little destructive to the eyes and to the
general health) by the aid of gas than by any other means. It must also
be borne in mind that, in this country at least, we have to fulfill the
conditions of artificial lighting under frequent differences of
temperature and barometric influence, exaggerated by the manner in which
our homes are built; and that for at least nine months of the year we
require heat as well as light in our dwellings, and that for the other
three months (excepting in some few favored localities) the nights are
often chilly, even though the days may be hot. Therefore, independently
of any effect produced by the lighting arrangements, there must be
widely different effects produced in the temperature and conditions of
the air in rooms by influences entirely beyond our control.
As an example of what I mean, a short time ago I had to preside over a
meeting which was held in a large room--one of two built exactly alike,
and in communication with each other by means of folding doors. These
rooms formed part of one of the best hotels in London--let us call it
the "Magnificent." Of course, it was lighted by electric glow lamps, in
accordance with the latest fashion in that department of artificial
lighting, viz., suspension lamps, in which the glow lamps grew out of
leaves and scrolls, twisted and twirled in and out, very much after the
pattern of our most aesthetic gas lamps, which, of course, are in the
style of the most artistic (late eighteenth century) oil lamps, which
were in imitation of the most classic Roman lamps, which followed the
Persian, and so on back to the time of Tubal Cain, the great
arch-artificer in metals, who most likely copied in metal some lamps he
had seen in shells or flints. Both rooms were heated by means of the
good old blazing coal fire so dear to a Briton's heart; and they were
ventilated with all due regard to the latest state of knowledge on the
subject among architects and builders. In fact, no pains had been spared
to make these rooms comfortable in the highest acceptation of the word.
There were, some of our members remarked, no gas burners to heat and
deteriorate the atmosphere, or to blacken the ceilings; and therefore,
under the brilliant sparkle of glow lamps, the summit of such human
felicity as is expected by a body of eighteen or twenty business men,
intent on dispatching business and restoring the lost tissue by means of
a nice little dinner afterward, ought, according to the calculations of
the architect of the building, to have been reached. I instance this
case because it is a typical one, which, under most aspects, does not
materially differ from the conditions of home life in such residences as
those whose occupiers are likely to use electric lighting. The rooms
were spacious (about 20 feet by 35 feet, and about 15 feet high); and
they were lighted during the day by means of large lantern
ceiling-lights, with double glass windows. The evening in question was
chilly, not to say cold.
Upon commencing our business, we all admired the comfort of the room;
but as time went on, most of the company began to complain of a little
draught on the head and back of the neck. The draught, which at first
was only a suspicion, became a certainty, and in another hour or so, by
the time our business was over, notwithstanding a screen placed before
the door, and a blazing fire, we were delighted to make a change to the
comfortable dining-room, which communicated with the room we had just
left by means of folding doors, closed with the exception of just
sufficient space left at one end of the room to allow a waiter to pass
in and out. Very curiously, before the soup was finished, we became
aware that the candles which assisted the electric glow lamps (merely
for artistic effect) began to flare in a most uncandlelike manner--the
flames turning down, as if some one were blowing downward on the wicks;
and at the same time the complaints of "Draughts, horrid draughts!"
became general, and from every quarter. Finding that, as the dinner went
on, the discomfort became unbearable, even although the doors were shut
and screens put before them, I gave up dining, and took to scientific
discovery. The result of a few moments' observation induced me to order
"those gas jets," which I saw peeping out from among the foliage of the
electroliers, to be lighted up. In two or three minutes the flames of
the candles burned upright and steadily, and in less than ten minutes
the draughts were no longer felt; in fact, the room became really
comfortable.
The reason of the change was simple. The stratum of air lying up at the
ceiling was comparatively cold. The column of heated air from the bodies
of the twenty guests, joined to the heat produced by the movements of
themselves and the waiters, together with the steam from the viands and
respiration, displaced the colder air at the ceiling, and notably that
coldest air lying against the surface of the glass. This cold air simply
dropped straight down, after the manner of a douche, on candles and
heads below. The remedy I advised was the setting up of a current of
hotter steam and air from the gas burners, which stopped the cooling
effect of the glass, and created a stratum of heated steam and air in
slow movement all over the ceiling. The effect was a comfortable
sensation of warmth and entire absence of draught all round the table.
Later on, to avoid the possibility of overheating the room, the gas was
put out, and the electric lights left to themselves. But before we left,
the chilliness and draughts began to be again felt.
The incident here narrated occurred at the end of the month of April
last, when we might reasonably have hoped to have tolerably warm nights.
It is therefore clear that in this instance neither electricity nor
candles could effectually replace gas for lighting purposes. They both
did the lighting, but they utterly failed to keep the currents of air
steady. I have always remarked draughts whenever I have remained any
length of time in rooms where the electric light is used. On a warm
evening the electric light and candles would undoubtedly have kept the
room cooler than gas, with the same kind of ventilation; I do not think
they would have put an end to cold draughts. This the steam from the gas
does in all fairly built rooms.
It is a well-known fact that dry air parts with its relatively small
amount of specific heat, in an almost incredibly rapid manner, to
anything against which it impinges. Steam, on the contrary, from its
great specific heat, remains in a heated state for a much longer time
than air. It is not so suddenly reduced to a low temperature, and in
parting with its own heat it communicates a considerable amount of
warmth to those bodies with which it comes in contact. Thus the products
of the combustion of gas (which are principally steam) serve a useful
purpose in lighting, by keeping at the ceiling level a certain stratum
of heated vapor, which holds up, as it were, the carbonic acid and
exhalation from the lungs given off by those using the room. The obvious
inference, therefore, is that if we take off these products from the
level of the ceiling, we shall take off at the same time the impure and
vitiated air. On the other hand, if we make use of a system of
artificial lighting, which does not produce any steam, then we shall
have to adopt means to keep the air at the ceiling level warm, in order
to prevent the heated impure air from descending in comparatively rapid
currents, after having parted with its heat to the ceiling. It may very
frequently be observed on chilly days that a number of currents of cold
air seem to travel about our rooms, although there may be no crevices in
the doors and windows sufficient to account for them; and, further, that
these currents of cold air are not noticed when the curtains are drawn
and the gas is lighted. The reason is that there is generally not enough
heat at the ceiling level in a room unlighted with gas to keep these
currents steady. Hence the complaints of chilliness which we constantly
hear when electric lights are used for the illumination of public
buildings. For example, at the annual dinner of the Institution of Civil
Engineers, held at the end of April last in the Conservatory of the
Horticultural Gardens, the heat from the five hundred guests, and from
an almost equal number of waiters and attendants, displaced the cold air
from the dome of the roof, and literally poured down on the assembly
(who were in evening dress) in a manner to compel many of them to put on
overcoats. If the Conservatory had been lighted with gas suspended below
the roof, this would not have been the case, because sufficient steam
would have been generated to stop these cold douches, and keep them up
in the roof. In fact, if electric lights are to be used in such a
building, it will be necessary to lay hot-water pipes in the roof, to
keep warm the upper as well as the lower stratum of air, and thus steady
the currents.
Having pointed out difficulties which arise under certain conditions of
the atmosphere in rooms built with care, to make them comfortable when
electric lighting is substituted for gas, I will lay before you some few
particulars relative to the condition of small rooms of about 12 ft. by
15 ft. by 10 ft., or any ordinary room such as may be found in the usual
run of houses in this country. The cubical contents of such a room
equals 1,700 cubic feet. If the room is heated by means of a coal fire,
we shall for the greatest part of the year have a quantity of air taken
out of it at about 2 feet from the floor by the chimney draught, varying
(according to atmospheric conditions and the state of the fire) from 600
to 2,000 or more cubic feet. This quantity of air must, therefore, be
admitted by some means or other into the room, or the chimney will, in
ordinary parlance, "smoke;" that is, the products of combustion, very
largely diluted with fresh air, will not all find their way up the flue
with sufficient velocity to overcome the pressure of the heavy cold air
at the top of the chimney. If no proper inlets for air are made, this
supply to the fire must be kept up from the crevices of the doors and
windows. In the line of these currents of cold air, or "draughts" as
they are usually called, it is impossible to experience any
comfort--quite the contrary; and colds, rheumatism, and many other
serious maladies are brought on through this abundant supply of fresh
air in the wrong way and place.
According to General Morin (one of the best authorities on ventilation),
300 cubic feet of air per hour are required for every adult person in
ordinary living rooms. Peclet says 250 cubic feet are sufficient; less
than this renders the atmosphere stuffy and unhealthy. It is generally
admitted that an average adult breathes out from 20 to 30 cubic inches
of steam and vitiated air per minute, or, as Dr. Arnott says, a quantity
equal in bulk to that of a full-sized orange. This vitiated air and
steam is respired at a temperature of 90 deg. Fahr.; and therefore, by
reason of this heat, it immediately ascends to the ceiling, together
with the heat and carbonic acid given off from the pores of the skin.
This fact, by the bye, can be clearly demonstrated by placing a person
in the direct rays from a powerful limelight or electric lamp, and thus
projecting his shadow sharply on a smooth white surface. It will be
observed that from every hair of the head and beard, and every fiber of
his clothing, a current of heated air in rapid movement is passing
upward toward the ceiling. These currents appear as white lines on the
surface of the wall; the cause probably being that the extreme
rarefaction of the air by the heat of the body enables the rays of light
to pass through them with less refraction than through the denser and
more moist surrounding cold air. An adult makes, on an average, about 15
respirations per minute, and therefore he in every hour renders to the
atmosphere of the room in which he is staying from 10 to 15 cubic feet
of poisonous air. This rises to the ceiling line, if it is not
prevented; and thus vitiates from 100 to 150 cubic feet of air to the
extent of 1 per cent, in an hour. General Morin thought that air was not
good which contained more than 1/2 per cent, of air which had been exhaled
from the lungs; and when we consider how dangerous to health these
exhalations are, we must admit that he was right in his view. Therefore
in one hour the 15 foot by 12 foot room is vitiated to more than 2 feet
from the ceiling by one person to the extent of 1/2 per cent., and it will
be vitiated by two persons to the extent of 1 per cent, in the same
time.
It must be remembered here that the degree of diffusion of the vitiated
air into the lower fresh air contained in the remaining 8 feet of the
height of the room depends very materially on the difference of
temperature between these upper and lower strata and the movements of
air in the room. The heavy poisonous vapors and gases fall into and
diffuse themselves among the fresh air of the lower strata--very readily
if they are nearly the same temperature as the upper, but scarcely at
all if the air at the ceiling line is much hotter. Hence it occurs that,
in warmed rooms of such size as I have mentioned, where one or two
petroleum lamps are used for lighting them, after two or three hours of
occupation by a family of three or four persons in winter weather, the
air at the ceiling line has become so poisonous that a bird dies if
allowed to breathe it for a very short time--sometimes, indeed, for only
a few minutes. With candles, if the illumination of the room is
maintained at the same degree as in the case of lamps, the contamination
of the air is very much worse. It is doubtless the case that poisonous
germs are rapidly developed in atmospheres which are called "stuffy;"
and although, in a healthy state of the body, we are able to breathe
them without perceptible harm, yet even then the slight headache and
uneasiness we feel is a symptom which does not suffer itself to be
lightly regarded, whenever, from some cause or other, the general
condition is weak.
The products of combustion from coal gas (which are steam and carbonic
acid mixed with an infinitesimal quantity of sulphur) are,
proportionately, far less injurious to animal life than the products
from an equal illuminating power derived from either oil or candles.
They are, however, it is certain, destructive to germ life; and
therefore, if taken off from the ceiling level, where they always
collect if allowed to do so, no possible inconvenience or danger to
health can be felt by any one in the room. But in our endeavors to take
off the foul air at the ceiling, we encounter our first serious check in
all schemes of ventilation. We draw the elevation and section of the
room, and put in our flues with pretty little black arrows flying out of
the outlets for vitiated air, and other pretty little red arrows flying
in at the inlets; but when we see our scheme in practice, the black
arrows will persist in putting their wings where their points ought to
be; in other words, flying into instead of out of the room.
One of the best ways of finding the true course of all the hot and cold
currents in a room is to make use of a small balloon, such as used to be
employed for ascertaining the specific gravity of gases; and, having
filled it with ordinary coal gas, balance it by weights tied on to the
car till it will rest without going up or down in a part of the room
where the air can be felt to be at about the mean temperature, and free
from draught. Then leave it to itself, to go where it will.
As soon as it arrives in a current of heated air, it will ascend,
passing along with the current, and descending or rising as the current
is either warm or cold. The effect of the cold fresh air from windows or
doors, as well as the effect of the radiant heat from the fire, can be
thus thoroughly studied. Some of our pet theories may receive a cruel
shock from this experiment; but, in the end, the ventilation of the room
will doubtless be benefited, if we apply the information obtained. It
will be discovered that the wide-throated chimney is the cause of the
little black arrows turning their backs on the right path and our
theoretical outlets for vitiated air becoming inlets. The chimney flue
must have an enormous supply of air, and it simply draws it from the
most easily accessible places. From 1,000 to 2,000 cubic feet of air per
hour is a large "order" for a small room. Therefore, until we have made
ample provision for the air supply to the fire, it is quite useless to
attempt to ventilate the upper part of the room, either by ventilating
gas lights or one of the cheap ventilators with little talc flappers,
opening into the chimney when there is an up draught, and shutting
themselves up when there is any tendency to down draught. The success of
these and all other ventilators depends upon there being a good supply
of air from under the door or through the spaces round the window
frames. These fresh air supplies are, of course, unendurable; but if one
of the spaces between the joists of the floor is utilized to serve as an
air conduit, and made to discharge itself under the fender (raised about
two inches for the purpose), quite another state of things will be set
up. Then the supply of air thus arranged for will satisfy the fire,
without drawing from the doors and windows, and at the same time supply
a small quantity of fresh air into the room. But the important fact that
the radiant heat from the fire will pass through the cold air without
warming it all must not be lost sight of. In reality, radiant heat only
warms the furniture and walls of the room or whatever intercepts its
rays. The air of the room is warmed by passing over these more or less
heated surfaces; and as it is warmed, it rises away to the ceiling.
Therefore, if we desire to warm any of this fresh air supplied to the
fire, it must be made to pass over a heated surface. The fender may be
used for this purpose by filling up the two inch space along the front,
as shown in the drawing, with coarse perforated metal. This will also
prevent cinders from getting under it. It will be found that for the
greater part of the year the chimney ventilator and the supply to the
fire will materially prevent "stuffiness," and keep those disagreeable
draughts under control, even although the room be lighted with a 3 light
chandelier burning a large quantity of gas.
[Illustration]
With improvements in gas burners, we may expect to light rooms perfectly
with a less expenditure of gas than we now do. But we cannot light a
room without in some measure creating heat; and I think I have shown
that we want this heat at the ceiling line for the greater part of the
year.
In summer we do not use gas for many hours; but, on the other hand, it
is more difficult, with an outside temperature at 65 deg. to 70 deg. Fahr., to
keep the air in proper movement in small rooms. There are also times in
the fall of the year, and also in spring, when the nights are unusually
warm; and, with a few friends in our rooms, the lighting becomes a "hot"
question, not to say a "burning" one. On these occasions we have to
resort to exceptional ventilation, which for ordinary every-day life
would be too much. It is then, and on summer nights, that the system of
ventilation by diffusion is most useful. To explain it, when two volumes
of air of different temperatures or specific gravities find themselves
on opposite sides of a screen or other medium, of muslin, cloth, or some
more or less porous substance, they diffuse themselves through this
medium with varying rapidity, until they become of equal density or
temperature. Therefore, if we fill the upper part of a window (which can
be opened, downward) with a strained piece of fine muslin or washed
common calico, the air in the room, if hotter than the external air,
will, when the window is more or less opened, pass out readily into the
cooler air, and the cooler air will pass in through the pores of the
medium. The hotter air passing out faster than the cooler air will come
in, no draught will be experienced; and the window may be opened very
widely without any discomfort from it.
It is, of course, quite impossible, in the limits of a paper, to do more
than indicate a means of ventilation which will be effective under most
circumstances of lighting with those gas burners and fittings usually
employed, and which will lend itself readily to modifications which will
be necessitated by the use of some of the newest forms of burners and
ventilating gas lights.
[Illustration]
In conclusion, I wish to draw attention to an important discovery I have
made in reference to blackened ceilings, for which, up to the present
time, gas has been chiefly blamed. I have long entertained the belief
that with a proper burner it is possible to obtain perfect combustion,
without any smoke; and a series of experiments with white porcelain
plates hung over some burners used in my own house proved conclusively
that the discoloration which spread itself all over my whitewashed
ceilings arose from the state of the atmosphere, which in all large
towns is largely mixed with heavy smoky particles, and from the dust or
dirt created in rooms by the use of coal fires as well as from the smoke
which, more frequently than one is at first supposed to imagine, escapes
from the fire-place into the room. I therefore, in two of my best rooms,
which required to have the ceilings whitened every year, substituted
varnished paper ceilings (light oak paper, simply put on in the usual
way, and varnished) instead of whitewash. I also changed the coal fires
for gas fires. These alterations have gone through the test of two
winters, and the ceilings are now as clean as when they were first done.
The burners have been used every night, and the gas fires every day,
during the two winters. No alteration has been made in the burners
employed, and no "consumers" have been used over them. If the varnished
paper ceilings are tried, I am sure that every one will like them better
than the time honored dirty whitewash, which is simply a fine sieve.
This fact is clearly shown by the appearance of the rafters, which,
after a short time, invariably show themselves whiter than the spaces
between.
* * * * *
ANDERS' TELEPHONE.
Mr. G.L. Anders' telephone, shown in the accompanying cut, combines in a
single apparatus a transmitter, A, a receiver, B, and a pile, C. The
transmitter consists of a felt disk, a, containing several large
apertures, and fixed by an insulating ring, c, to a metallic disk, d,
situated within the box, D. The apertures, b, are filled with powdered
carbon, e, and are covered by a thin metal plate, f, which is fixed to
the insulating ring, c, by means of a metallic washer, g. Back of the
transmitter is arranged the receiver, B, which consists of an ordinary
electro-magnet with a disk in front of its poles. The pile, C, placed
behind the receiver, consists of a piece of carbon, h, held by a
partition, i, and covered with a salt of mercury, and of a plate of
zinc, l, which is held at a distance from the mercurial salt by a
spring, m, fixed to the insulating piece, n.
[Illustration: ANDERS TELEPHONE]
When the button, o, which is a poor conductor, is pressed, the zinc
plate, l, comes into contact with the mercurial salt, and the circuit is
closed through the line wire 1, the pile, the receiver, the transmitter,
and the line wire 2, while when the button is freed the current no
longer passes. The apparatus, then, can serve as a receiver or
transmitter only when the button is pressed.--_Bull. de la Musee de
l'Industrie_.
* * * * *
BROWN'S ELECTRIC SPEED REGULATOR.
When the sea is rough, and the screw leaves the water as a consequence
of the ship's motions, the rotary velocity of the screw and engine
increases to a dangerous degree, because the resistance that the screw
was meeting in the water suddenly disappears. When the screw enters the
water again, the resistance makes itself abruptly felt, and causes
powerful shocks, which put both the screw and engine in danger. Ordinary
regulators are powerless to overcome this trouble, since their
construction is such that they act upon the engine only when the excess
of velocity has already been reached.
Several remedies have been proposed for this danger. For example, use
has been made of a float placed in a channel at the side of the screw,
and which closes the moderator valve by mechanical means or by
electricity when the screw descends too low or rises too high.
[Illustration: BROWN'S ELECTRIC SPEED REGULATOR.]
Mr. Brown's system is based upon a new idea. The apparatus (see figure)
consists of two contacts connected by an electric circuit. One of them,
b, is fixed to the ship in such a way as to be constantly in the water,
while the other, a, corresponds to the position above which the screw
cannot rise without taking on a dangerous velocity. In the normal
situation of the ship, the electric circuit, c (in which circulates a
current produced by a dynamo, d), is closed through the intermedium of
the water, which establishes a connection between the two contacts. When
the contact, a, rises out of the water, the current is interrupted. The
electro, d, then frees its armature, f, and the latter is pulled back by
a spring--a motion that sets in action a small steam engine that closes
the moderator valve. When the contact, a, is again immersed, the
electro, e, attracts its armature, and thus brings the moderator valve
back to its normal position. It is clear that the contact, a, must be
insulated from the ship's side.
Several contacts, a, might be advantageously arranged one above another,
in order to close the moderator valve more or less, according to the
extent of the screw's rise or fall.
* * * * *
MAGNETO-ELECTRIC CROSSING SIGNAL.
We illustrate to-day a new application of electricity to railroad
crossing signaling which the Pennsylvania Steel Company, of Steelton,
Pa., has just perfected. By its operation an isolated highway crossing
in the woods or any lonely place can be made perfectly safe, and that,
too, without the expense of gates and a man to work them or of a
flagman. It is surely a great improvement over the old methods, and it
is likely to have a large sale. In addition to considerations of safety,
possible saving in salaries to railroad companies by its use will be
great. This device is more reliable than a human being, and can make any
crossing safe to which it is applied. Its operation is described as
follows:
[Illustration: FIG. 2.--MAGNETO-ELECTRIC CROSSING SIGNAL]
The illustration shows the device as used on a single track railroad,
where it is so arranged as to be operated only by trains approaching the
crossing (i.e., in the form illustrated, from the right). A similar box
on the other side of the crossing is used for trains approaching in the
other direction. Two plates connected by a link, and pivoted, are placed
alongside of one rail, close enough to it to be depressed by the treads
of the wheels. By another link, one of the plates called the rock plate
(the one to the right) is connected to a rock shaft which extends
through a strong bearing into the heavy iron case or box shown, at a
suitable distance from the rail, within which an electric generator is
placed; the whole being mounted and secured upon the ends of two long
ties framed to receive it.
The action of this rock plate is peculiar. It is pivoted at the rear
end, not to a fixed point, but to a short crank arm, the bearing for
which is inclosed in the small box shown. As the first wheel of a train
which is approaching in the desired direction (from the right in the
engraving) touches it, it will be seen that it must not only depress it,
but produce a slight forward motion, causing a corresponding rotary
motion in the rock shaft which actuates the apparatus. On the other
hand, when a train is approaching from the other direction, or has
already passed the crossing, its wheels strike first the curved plate to
the left of the illustration, and by means of the peculiar link
connections shown, depress the rock plate so as to clear the wheels
before the wheels touch it, but the depression is directly vertical, so
that it does not give any horizontal motion to it, which would have the
effect of actuating the rock shaft. Consequently, trains pass over the
apparatus in one direction without having any effect upon it whatever,
the different point at which the same force is applied to the rock plate
giving the latter an entirely different motion.
[Illustration: FIG. 2.--MAGNETO-ELECTRIC CROSSING SIGNAL]
The slight rotary motion which is in this way communicated to the rock
shaft, when a train is approaching in the right direction, compresses a
spring inside the case. As each wheel passes off the rock plate, the
reaction of the spring throws it up again to its former position, giving
additional speed to the gearing within, which is set in motion at the
passage of the first wheel, and operates the electric "generator." The
spring is really the motive power of the alarm. A small but heavy
fly-wheel is connected with the apparatus, the top of which is just
visible in the engraving, which serves to store up power to run the
"generator," which is nothing more than a small dynamo, for the
necessary number of seconds after the rear of the train has passed. The
dynamo dispenses with all need for batteries, and reduces the work of
maintenance to occasionally refilling the oil-cups and noticing if any
part has been broken.
A suitable wire circuit is provided, commencing at the generator with
insulated and protected wire, and continued with ordinary telegraph
wire, which can be strung on telegraph poles or trees leading to the
electric gong, Fig. 2, which rings as long as the armature revolves. It
is a simple matter so to proportion the mechanism for the required
distance and speed that the revolutions of the armature and the ringing
of the gong shall continue until the train reaches the crossing; and as
each wheel acts upon the apparatus, the more wheels there are in the
train the longer the bell will ring, a very convenient property, since
the slowest trains have nearly always the most wheels. The practical
limits to the ringing of the gong are that it will stop sounding after
the head of the train has passed the crossing and before or very soon
after the rear has passed. A "wild" engine running very slowly might not
actuate the signal as long as was desirable, but even then it is not
unreasonably claimed the warning would probably last long enough for all
practical requirements, as a team approaching a crossing at eight miles
per hour takes 42 seconds to go 500 feet. All the bearings of any
importance are self-lubricated by oil cups, the whole apparatus being
designed to require inspection not more than once a month. The iron case
when shut is water-tight, and when duly locked cannot be maliciously
tampered with without breaking open the case; so that, the manufacturers
claim, it will not be essential to examine it more than once a month.
The parts outside the case are all strong and heavy, and not likely to
get out of order, while easily inspected.
The apparatus can be used for announcing trains as well as sounding
alarms, as the gongs can be placed upon any post or building. The gong
has a heavy striker, and makes a great deal of noise, so that no one
should fail to hear it.--_Railway Review_.
* * * * *
THE SIZES OF BLOOD CORPUSCLES.
Professor Theodore G. Wormley, in the new edition of his work, gives the
following sizes of blood corpuscles, as measured by himself and
Professor Gulliver. We have only copied the sizes for mammals and birds.
It will be seen that, with three or four exceptions, the sizes obtained
by the two observers are practically the same:
Mammals Wormley. Gulliver.
Man 1-3250 1-3260
Monkey 1-3382 1-3412
Opossum 1-3145 1-3557
Guinea pig 1-3223 1-3538
Kangaroo 1-3410 1-3440
Muskrat 1-3282 1-3550
Dog 1-3561 1-3532
Rabbit 1-3653 1-3607
Rat 1-3652 1-3754
Mouse 1-3743 1-3814
Pig 1-4268 1-4230
Ox 1-4219 1-4267
Horse 1-4243 1-4600
Cat 1-4372 1-4404
Elk 1-4384 1-3938
Buffalo 1-4351 1-4586
Wolf (prairie) 1-3422 1-3600
Bear (black) 1-3656 1-3693
Hyena 1-3644 1-3735
Squirrel (red) 1-4140 1-4000
Raccoon 1-4084 1-3950
Elephant 1-2738 1-2745
Leopard 1-4390 1-4319
Hippopotamus 1-3560 1-3429
Rhinoceros 1-3649 1-3765
Tapir 1-4175 1-4000
Lion 1-4143 1-4322
Ocelot 1-3885 1-4220
Mule 1-3760
Ass 1-3620 1-4000
Ground squirrel 1-4200
Bat 1-3966 1-4173
Sheep 1-4912 1-5300
Ibex 1-6445
Goat 1-6189 1-6366
Sloth 1-2865
Platypus (duck-billed) 1-3000
Whale 1-3099
Capybara 1-3164 1-3190
Seal 1-3281
Woodchuck 1-3484
Muskdeer 1-12325
Beaver 1-3325
Porcupine 1-3369
Llama, Long diam. 1-3201 1-3361
Short " 1-6408 1-6229
Camel, Long diam. 1-3331 1-3123
Short " 1-5280 1-5876
WORMLEY GULLIVER.
Birds. Length. Breadth. Length. Breadth.
Chicken 1-2080 1-3483 1-2102 1-3466
Turkey 1-1894 1-3444 1-2045 1-3599
Duck 1-1955 1-3504 1-1937 1-3424
Pigeon 1-1892 1-3804 1-1973 1-3643
Goose 1836 1-3839
Quail 2347 1-3470
Dove 2005 1-3369
Sparrow 2140 1-3500
Owl 1736 1-4076
The subject of minute measurements was discussed in an interesting
manner in an address before the Microscopical Section of the A.A.A.S.
last year, an abstract of which was published in this journal, vol. v.,
p. 181.
The slight differences in size accurately given in this table are not
always appreciable under modern amplification, but under a power of
1,150 diameters "corpuscles differing by the 1-100000 of an inch are
readily discriminated." For the conclusions of Prof. Wormley as regards
the possibility of identifying blood of different animals, the reader is
referred to his book on Micro-Chemistry of Poisons.--_Amer. Micro.
Jour._
* * * * *
THE ABSORPTION OF PETROLEUM OINTMENT AND LARD BY THE SKIN.
[Footnote: From the _American Druggist_.]
E. Joerss has investigated the question whether ointments made with
vaseline or other petroleum ointments are really as difficult of
resorption by the skin, or of yielding their medicinal ingredients to
the latter, as has been asserted. In solving this question, he
considered himself justified in drawing conclusions from the manner in
which such compounds behaved toward _dead_ animal membrane. If any kind
of osmosis could take place, he argued, from ointments prepared with
vaseline, etc., through dead membranes, such osmosis would most probably
also take place through living membranes. At all events, the endosmotic
or exosmotic action of the skin of a living body must necessarily play
an important _role_ in the absorption of medicinal agents; and, on the
other hand, it is plain that fats, which render the living skin
impermeable, necessarily also diminish or entirely neutralize its
osmotic action. To test this, the author made the following experiments:
Bladder was tied over the necks of three wide-mouthed vials, with
bottoms cut off, and each was filled with iodide of potassium ointment.
No. 1 contained an ointment made with lard.
No. 2, one made with unguentum paraffini (_Germ. Pharm_.), and
No. 3, one made with unguentum paraffini mixed with 3 per cent. of lard.
All three vials were then suspended in beakers filled with water. After
standing twenty-four hours at the ordinary temperature, the contents of
none of the beakers gave any iodine reaction. After having been placed
into a warm temperature, between 25-37 deg. C., all three showed iodine
reactions after three hours, Nos. 2 and 3 very strongly, No. 1 (with
lard alone) very faintly.
The same experiment was now repeated, with the precaution that the
bladder was previously washed completely free from chlorine. Each vial
was suspended, at a temperature of 25-27 deg. C., in 50 grammes of distilled
water. After three hours, the contents of No. 1 (containing the ointment
made with _lard_) gave _no_ iodine reaction; the contents of the other
two, however, gave traces. After eight hours no further change had taken
place. The temperature was now raised to 30-35 deg. C., and kept so for
eight hours. All three beakers now gave a strong iodine reaction, 0.2
c.c. of normal silver solution being required for each 15 grammes of the
contents of the beakers.
In addition to the iodide, some of the fatty base had osmosed through
the membrane in each case.
The next experiment was made by substituting a piece of the skin (freed
from chlorine by washing) of a freshly killed sheep for the bladder. The
ointment in No. 3 in this case was made with 10 per cent. of lard. No
reaction was obtained, at the ordinary temperature, after twelve hours,
nor after eight more hours, at a temperature of 25-30 deg. C. After letting
them stand for eight hours longer at 30-37 deg. C., a faint reaction was
obtained in the case of the ointment made with unguentum paraffini; a
still fainter with No. 3; but no reaction at all with No. 1 (that made
with lard). None of the fats passed through by osmosis. After eight
hours more, the iodine reaction was quite decisive in all cases, but no
fat had passed through even now. On titrating 20 grammes of the contents
of each beaker,
No. 1 required 0.5 c.c. of silver solution.
No. 3 " 0.5 c.c. "
No. 2 " 0.7 c.c. "
showing that the most iodine had osmosed in the case of the ointment
made with unguentum paraffini (equivalent to vaseline).
* * * * *
THE TAILS OF COMETS.
I.--If we throw a stone into the water, a wave will be produced that
will extend in a circle. The size of this wave and the velocity with
which it extends depend upon the size of the stone, that is to say, upon
the intensity of the mechanical action that created it. The extent and
depth of the water are likewise factors.
If we cause a cord to vibrate in the water, we shall obtain a succession
of waves, the velocity and size of which will be derived from the cord's
size and the intensity of its action. These waves, which are visible
upon the surface, constitute what I shall call _mechanical waves_. But
there will be created at the same time other waves, whose velocity of
propagation will be much greater than that of the mechanical ones, and
apparently independent of mechanical intensity. These are _acoustic
waves_. Finally, there will doubtless be created _optical waves_, whose
velocity will exceed that of the acoustic ones. That is to say, if a
person fell into water from a great height, and all his senses were
sufficiently acute, he would first perceive a luminous sensation when
the first optical wave reached him, then he would perceive the sound
produced, and later still he would feel, through a slight tremor, the
mechanical wave.[1]
[Footnote 1: Certain persons, as well known, undergo an optical
impression under the action of certain sounds.]
[Illustration: I]
Under the action of the same mechanical energy there form, then, in a
mass of fluid, waves that vary in nature, intensity, and velocity of
propagation; and although but three modes appreciable to our senses have
been cited, it does not follow that these are the only ones possible.
We may remark, again, that if we produce a single wave upon water, it
will be propagated in a uniform motion, and will form in front of it
successive waves whose velocity of propagation is accelerated.
This may explain why sounds perceived at great distances are briefer
than at small ones. A detonation that gives a quick dead sound at a few
yards is of much longer duration, and softer at a great distance.
The laws that govern the system of wave propagation are, then, very
complex.
[Illustration: II]
II.--If an obstacle be in the way of the waves, there will occur in each
of them an _alteration_, a break, which it will carry along with it to a
greater or less distance. This succession of alterations forms a trace
behind the obstacle, and in opposition to the line of the centers.
Finally, if the obstacle itself emits waves in space that are of less
intensity then those which meet it, these little waves will extend in
the wake of the large ones, and will form a trace of parabolic form
situated upon the line of the centers.
[Illustration: III]
III.--Let us admit, then, that the sun, through the peculiar energy that
develops upon its surface or in its atmosphere, engenders in ethereal
space successive waves of varying nature and intensity, as has been said
above, and let us admit that its _mechanical_ waves are traversed
obliquely (Fig. 1) by any spherical body--by a comet, for example; then,
under the excitation of the waves that it is traversing, and through its
velocity, the comet will itself enter into action, and produce
mechanical waves in its turn. As the trace produced in the solar waves
consists of an agitation of the ether on such trace, it will become
apparent, if we admit that every luminous effect is produced by an
excitation--a setting of the ether in vibration. The mechanical waves
engender of themselves, then, an emission of optical waves that render
perceptible the alteration which they create in each other.
Let a be the position of the comet. The altered wave, a, will carry
along the mark of such alteration in the direction a b, while at the
same time extending transversely the waves emitted by the comet. During
this time the comet will advance to a', and the wave will be altered in
its turn, and carry such alteration in the direction, a' b'.
The succession of all these alterations will be found, then, upon a
curve a'' d' d, whose first elements, on coming from the comet, will be
upon the resultant of the comet's velocity, and of the propagation of
the solar waves. Consequently, the slower the motion of the comet, with
respect to the velocity of the solar waves, the closer will such
resultant approach the line of centers, and the more rectilinear will
appear the trace or tail of the comet.
[Illustration: IV]
IV.--If the comet have satellites, we shall see, according to the
relative position of these, several tails appear, and these will seem to
form at different epochs. If c and s be the positions of a comet and a
satellite, it will be seen that if, while the comet is proceeding to c',
the satellite, through its revolution around it, goes to s', the traces
formed at c and s will be extended to d and d', and that we shall have
two tails, c' d and s' d', which will be separated at d and d' and seem
to be confounded toward c' s'.
V.--When the comet recedes from the sun, the same effect will occur--the
tail will precede it, and will be so much the more in a line with the
sun in proportion as the velocity of the solar waves exceeds that of the
comet.
If we draw a complete diagram (Fig. 4), and admit that the alteration of
the solar waves persists indefinitely, we shall see (supposing the
phenomenon to begin at a) that when the comet is at a 1, the tail will
and be at a 1 b; when it is a 2 the tail will be at a 2 b'; and when it
is at a 4, the tail will have become an immense spiral, a 4 b'''. As in
reality the trace is extinguished in space, we never see but the origin
of it, which is the part of it that is constantly new--that is to say,
the part represented in the spirals of Fig. 4.
The comet of 1843 crossed the perihelion with a velocity of 50 leagues
per second; it would have only required the velocity of the solar waves'
propagation to have been 500 leagues per second to have put the tail in
a sensibly direct opposition with the sun.
Knowing the angle [gamma] (Fig. 5) that the tangent to the orbit makes
with the sun at a given point, and the angle [delta] of the track upon
such tangent, as well as the velocity v of the comet, we can deduce
therefrom the velocity V of the solar waves by the simple expression:
V = v x (sinus [delta] / sinus([gamma] - [delta])) or (Fig. 1),
V = da/t'',
t'' being the time taken to pass over aa''.
[Illustration: V]
VI.--The tail, then, is not a special matter which is transported in
space with the comet, but a disturbance in the solar waves, just as
sound is an atmospheric disturbance which is propagated with the
velocity of the sonorous wave, although the air is not transported. The
tail which we see in one position, then, is not that which we see in
another; it is constantly renewed. Consequently, it is easy to conceive
how, in as brief a time as it took the comet of 1843 to make a half
revolution round the sun, the tail which extended to so great a distance
appeared to sweep the 180 deg. of space, while at the same time remaining in
opposition to the great luminary.
[Illustration: VI]
The spiral under consideration may be represented practically. If to a
vertical pipe we adapt a horizontal one that revolves with a certain
velocity, and throws out water horizontally, it will be understood that,
from a bird's eye view, the jet will form a spiral. Each drop of water
will recede radially in space, the spiral will keep forming at the jet,
and if, through any reason, the latter alone be visible, we shall see a
nearly rectilinear jet that will seem to revolve with the pipe.
Finally, if the jet be made to describe a curve, m n (Fig. 4), while it
is kept directed toward the opposite of a point, c, the projected water
will mark the spiral indicated, and this will continue to widen, and
each drop will recede in the direction shown by the arrows.
[Illustration: VII]
VII.--It seems to result from this explanation that all the planets and
their satellites ought to produce identical effects, and have the
appearance of comets. In order to change the conditions, it suffices to
admit that the ethereal mass revolves in space around the sun with a
velocity which is in each place that of the planets there; and this is
very reasonable if, admitting the nebular hypothesis, we draw the
deduction that the cause that has communicated the velocity to the
successive rings has communicated it to the ethereal mass.
The planets, then, have no appreciable, relative velocity in space, and
for this reason do not produce mechanical waves; and, if they become
capable of doing so through a peculiar energy developed at their
surface, as in the case of the sun, they are still too weak to give very
perceptible effects. The satellites, likewise, have relatively too
feeble velocities.
The comet, on the contrary, directly penetrates the solar waves, and
sometimes has a relatively great velocity in space. If its proper
velocity be of directly opposite direction to that of the ethereal
mass's rotation, it will then be capable of producing sufficiently
intense mechanical effects to affect our vision.
VIII.--Finally, seeing the slight distances at which these stars pass
the sun, the attraction upon the comet and its satellites may be very
different, and the velocity of rotation of the latter, being added to or
deducted from that of the forward motion, there may occur (as in the
case shown in Fig. 6) a separation of a satellite from the principal
star. The comet then appears to separate into two, and each part follows
different routes in space; or, as in Fig. 7, one of the satellites may
either fall into the sun or pursue an elliptical orbit and become
periodical, while the principal star may preserve a parabolic orbit, and
make but one appearance.--_A. Goupil._
* * * * *
THE DOUBLE ROLE OF THE STING OF THE HONEY BEE.
[Footnote: Translated from an article entitled "Ueber eine doppelrolle
des stachels der honigbienen" in _Deutschamerikanische Apotheker
Zeitung_, 15 Jan., 1885, Jahrg. 5, p. 664; there reprinted from _Ind.
Blatter_.]
Very important and highly interesting discoveries have recently been
made in regard to a double role played by the sting of the honey bee.
These discoveries explain some hitherto inexplicable phenomena in the
domestic economy of the ants. It is already known that the honey of our
honey bees, when mixed with a tincture of litmus, shows a distinct red
color, or, in other words, has an acid reaction. It manifests this
peculiarity because of the volatile formic acid which it contains. This
admixed acid confers upon crude honey its preservative power. Honey
which is purified by treatment with water under heat, or the so-called
honey-sirup, spoils sooner, because the formic acid is volatilized. The
honey of vicious swarms of bees is characterized by a tart taste and a
pungent odor. This effect is produced by the formic acid, which is
present in excess in the honey. Hitherto it has been entirely unknown in
what way the substratum of this peculiarity of honey, the formic acid in
the honey, could enter into this vomit from the honey stomach of the
workers. Only the most recent investigations have furnished us an
explanation of this process. The sting of the bees is used not only for
defense, but quite principally serves the important purpose of
contributing to the stored honey an antizymotic and antiseptic
substance.
The observation has recently been made that the bees in the hive, even
when they are undisturbed, wipe off on the combs the minute drops of bee
poison (formic acid) which from time to time exude from the tip of their
sting. And this excellent preservative medium is thus sooner or later
contributed to the stored honey. The more excitable and the more ready
to sting the bees are, the greater will be the quantity of formic acid
which is added to the honey, and the admixture of which good honey
needs. The praise which is so commonly lavished upon the Ligurian race
of our honey bees, which is indisposed to sting--and such praise is
still expressed at the peripatetic gatherings of German bee-masters--is
therefore from a practical point of view a false praise. Now we
understand also why the stingless honey bees of South America collect
little honey. It is well known that never more than a very small store
of honey is found in felled trees inhabited by stingless _Melipona_.
What should induce the _Melipona_ to accumulate stores which they could
not preserve? They lack formic acid. Only three of the eighteen
different known species of honey bees of northern Brazil have a sting. A
peculiar phenomenon in the life of certain ants has always been
problematical, but now it finds also its least forced explanation. It is
well known that there are different grain-gathering species of ants. The
seeds of grasses and other plants are often preserved for years in their
little magazines, without germinating. A very small red ant, which drags
grains of wheat and oats into its dwellings, lives in India. These ants
are so small that eight or twelve of them have to drag on one grain with
the greatest exertion. They travel in two separate ranks over smooth or
rough ground, just as it comes, and even up and down steps, at the same
regular pace. They have often to travel with their booty more than a
thousand meters, to reach their communal storehouse. The renowned
investigator Moggridge repeatedly observed that when the ants were
prevented from reaching their magazines of grain, the seeds begun to
sprout. The same was the case in abandoned magazines of grain. Hence the
ants know how to prevent the sprouting of the grains, but the capacity
for sprouting is not destroyed. The renowned English investigator John
Lubbock, who communicates this and similar facts in his work entitled
"Ants, Bees, and Wasps," adds that it is not yet known in what way the
ants prevent the sprouting of the collected grains. But now it is
demonstrated that here also it is only the formic acid, whose
preservative influence goes so far that it can make seed incapable of
germination for a determinate time or continuously.
It may be mentioned that we have also among us a species of ant which
lives on seeds, and stores these up. This is our _Lasius niger_, which
carries seeds of _Viola_ into its nests, and, as Wittmack has
communicated recently to the Sitzungsberichte der gesellschaft
naturforschender freunde zu Berlin, does the same with the seeds of
_Veronica hederaefolia_.
Syke states in his account of an Indian ant, _Pheidole providens_, that
this species collects a great store of grass-seeds. But he observed that
the ants brought their store of grain into the open air to dry it after
the monsoon storms. From this it appears that the preservative effect of
the formic acid is destroyed by great moisture, and hence this drying
process. So that among the bees the honey which is stored for winter
use, and among the ants the stores of grain which serve for food, are
preserved by one and the same fluid, formic acid.
EDITORIAL NOTE.
This same theory has been suggested many times by our most advanced
American bee-keepers. It has been hinted that this same formic acid was
what made honey a poison to many people, and that the sharp sting of
some honey, notably that from bass wood or linden, originated in this
acid from the poison sac. If this is the correct explanation, it seems
strange that the same kind of honey is always peculiar for greater or
less acidity as the case may be. We often see bees with sting extended
and tipped with a tiny drop of poison; but how do we know that this
poison is certainly mingled with the honey? Is this any more than a
guess?--_A.J. Cook, in Psyche_.
* * * * *
CHLORIDES IN RAINFALL OF 1884.
We are apt to regard the rain solely as a product of distillation, and,
as such, very pure. A little reflection and a very slight amount of
experimental examination will quickly disabuse those who have this
mistaken and popular impression of their error. A great number of bodies
which arise from industrial processes, domestic combustion of coal,
natural changes in vegetable and animal matter, terrestrial disturbances
as tornadoes and volcanic eruptions, vital exhalations, etc., are
discharged into the atmosphere, and, whether by solution or mechanical
contact, descend to the surface of the earth in the rain, leaving upon
its evaporation in many instances the most incontestable evidences of
their presence. The acid precipitation around alkali and sulphuric acid
works is well known; the acid character of rains collected near and in
cities, and the remarkable ammoniacal strength of some local rainfalls,
have been fully discussed. The exhaustive experiments of Dr. Angus Smith
in Scotland, and the interesting reports of French examiners, have made
the scientific world familiar, not only qualitatively but
quantitatively, with the chemical nature of some rains, as well as with
their solid sedimentary contents.
Some years ago my attention was unpleasantly drawn to the fact that the
rain water in our use reacted for chlorine; and on finding this due
solely to the washing out from the atmosphere of suspended particles of
chloride of sodium or other chlorides or free chlorine, it appeared
interesting to determine the average amount of these salts in the rain
water of the sea coast. The results given in this paper refer to a
district on Staten Island, New York harbor, at a point four miles from
the ocean, slightly sheltered from the ocean's immediate influence by
the intervention of low ranges of hills. They were communicated to the
Natural Science Association of Staten Island, but the details of the
observations may prove of interest to the readers of the _Quarterly_,
and may there serve as a record more widely accessible.
It has long been recognized that the source of chlorine in rainfalls
near the sea was the sea itself, the amount of chlorides, putting aside
local exceptions arising from cities or manufactories, increasing with
the proximity of the point of observation to the ocean, and also showing
a marked relation to the exposure of the position chosen to violent
storms. Thus the west coast rainfalls of Ireland contain larger
quantities of chlorides than those of the east, and the table given by
Dr. Smith shows the variations in neighboring localities on the same
seafront. The chlorides of the English rains diminish as the observer
leaves the sea coast. In the following observations the waters of
thirty-two rains were collected, the chlorine determined by nitrate of
silver in amounts of the water varying from one liter to one-half a
liter, and in some instances less. While it is likely that some of the
chlorine was due to the presence of chlorides other than common salt, as
the position of the point of observation is not removed more than a mile
from oil distilleries and smelting and sulphuric acid works in New
Jersey, yet this could not even generally have been so, as the rain
storms came, for the greater number of instances, from the east, in an
opposite direction to the position of the factories alluded to. It has
also been noticed by Mr. A. Hollick, to whom these observations were of
interest, that in heavy storms a salt film often forms upon fruit
exposed to the easterly gales upon the shores of the island.
The yearly average for chlorine is 0.228 grain per gallon; for sodic
chloride, 0.376 grain. The total rainfall in our region for 1884, as
reported by Dr. Draper at Central Park, was 52.25 inches, somewhat
higher than usual, as the average for a series of years before gives 46
inches; but taking these former figures, we find that for that year
(1884) each acre of ground received, accepting the results obtained by
my examination, 76.24 avoirdupois pounds of common salt, if we regard
the entire chlorine contents of the rains as due to that body, or 46.23
pounds of chlorine alone.
In comparison with this result, we find that at Caen, in France, an
examination of the saline ingredients of the rain gave for one year
about 85 pounds of mineral matter per acre, of which 40 pounds were
regarded as common salt.
Although chlorine is almost constantly present in plant tissues, it is
not indispensable for most plants, and for those assimilating it in
small amounts, our rainfall would seem to offer an ample supply. These
facts open our eyes to the possible fertilizing influence of rains, and
they also suggest to what extent rains may exert a corrosive action when
they descend charged with acid vapors.--_L.P. Gratacap, in School of
Mines Quarterly_.
* * * * *
THE CHROMATOSCOPE.
Some time ago Mr. J.D. Hardy devised an instrument, which he has named a
chromatoscope, so easily made by any one who has a spot lens that we
take the following description from the _Journal_ of the Royal
Microscopical Society: "Its chief purpose is that of illuminating and
defining objects which are nonpolarizable, in a similar manner to that
in which the polariscope defines polarizable objects. It can also be
applied to many polarizable objects. This quality, combined with the
transmission of a greater amount of light than is obtainable by the
polariscope, renders objects thus seen much more effective. It is
constructed as follows: Into the tube of the spot lens a short tube is
made to move freely and easily. This inner tube has a double flange, the
outer one, which is milled, for rotating, and the inner one for carrying
a glass plate. This plate is made of flat, clear glass, and upon it are
cemented by a very small quantity of balsam three pieces of colored
(stained) glass, blue, red, and green, in the proportion of about 8, 5,
and 3. The light from the lamp is allowed to pass to some extent through
the interspaces, and is by comparison a strong yellow, thus giving four
principal colors. Secondary colors are formed by a combination of the
rays in passing through the spot lens.
"The stained glass should be as rich in color and as good in quality as
possible, and a better effect is obtained by three pieces of stained
glass than by a number of small pieces. The application of the
chromatoscope is almost unlimited, as it can be used with all objectives
up to the 1/8. Transparent objects, particularly crystals which will not
polarize, diatoms, infusoria, palates of mollusks, etc., can not only be
seen to greater advantage, but their parts can be more easily studied.
As its cost is merely nominal, it can be applied to every instrument,
large or small; and when its merits and its utility by practice are
known, I am confident that it will be considered a valuable accessory to
the microscope."
* * * * *
Prof. W.O. Atwater, as the results of a series of experiments, finds,
contrary to the general opinion of chemists, that plants assimilate
nitrogen from the atmosphere. They take up the greatest quantity when
supplied with abundant nourishment from the soil. Well fed plants
acquired fully one-half their total nitrogen from the air. It seems
probable that the free nitrogen of the air is in some way assimilated by
the plants.
* * * * *
A catalogue, containing brief notices of many important scientific
papers heretofore published in the SUPPLEMENT, may be had gratis at this
office.
* * * * *
THE SCIENTIFIC AMERICAN SUPPLEMENT.
PUBLISHED WEEKLY.
TERMS OF SUBSCRIPTION, $5 A YEAR.
Sent by mail, postage prepaid, to subscribers in any part of the United
States or Canada. Six dollars a year, sent, prepaid, to any foreign
country.
All the back numbers of THE SUPPLEMENT, from the commencement, January
1, 1876, can be had. Price, 10 cents each.
All the back volumes of THE SUPPLEMENT can likewise be supplied. Two
volumes are issued yearly. Price of each volume, $2.50, stitched in
paper, or $3.50, bound in stiff covers.
COMBINED RATES--One copy of SCIENTIFIC AMERICAN and one copy of
SCIENTIFIC AMERICAN SUPPLEMENT, one year, postpaid, $7.00.
A liberal discount to booksellers, news agents, and canvassers.
MUNN & CO., PUBLISHERS,
361 BROADWAY, NEW YORK, N. Y.
* * * * *
PATENTS.
In connection with the SCIENTIFIC AMERICAN, Messrs. MUNN & Co. are
Solicitors of American and Foreign Patents, have had 40 years'
experience, and now have the largest establishment in the world. Patents
are obtained on the best terms.
A special notice is made in the SCIENTIFIC AMERICAN of all inventions
patented through this Agency, with the name and residence of the
Patentee. By the immense circulation thus given, public attention is
directed to the merits of the new patent, and sales or introduction
often easily effected.
Any person who has made a new discovery or invention can ascertain, free
of charge, whether a patent can probably be obtained, by writing to MUNN
& Co.
We also send free our Hand Book about the Patent Laws, Patents, Caveats,
Trade Marks, their costs, and how procured. Address
MUNN & CO., 361 BROADWAY, NEW YORK.
Branch Office, 622 and 624 F St., Washington, D.C.
Back to Full Books
|