Scientific American Supplement, No. 803, May 23, 1891
by
Various
Part 2 out of 3
4. That the backing must be as rigid as possible.
* * * * *
[FROM ENGINEERING.]
THE COMPRESSED AIR SYSTEM OF PARIS.
The demand for compressed air as a motive power is constantly
increasing in Paris; the company, according to its official reports,
is financially prosperous, and it seems difficult to understand how it
should continue as an actively going concern, unless it at all events
paid its way. The central station of St. Fargeau, originally started
on modest lines, for maintaining a uniform time by pneumatic pressure
throughout Paris, has grown rapidly to very large proportions, though
it has never been able to supply the demand made on it for power; and
at the present time a second and still larger station is being
constructed in another part of Paris. We confess that we do not
understand why such large sums of money should continue to be spent if
the enterprise is not commercially a sound one, nor how men of such
eminence in the scientific world as Professor Riedler should, without
hesitation, risk their reputation on the correctness of the system, if
it were the idle dream of an enthusiast, as many persons--chiefly
those interested in electric transmission--have declared it to be.
[Illustration: Fig. 1.--MAP OF PARIS WITH ST. FARGEAU STATION]
In describing the developments that have taken place during the last
two years, we shall confine ourselves entirely to the details of a
report recently made on the subject by Professor Riedler. As soon as
it became evident that a very largely increased installation was
necessary, it was determined that the new central station should be as
free as possible from the defects of the first one. These defects,
which were the natural results of the somewhat hasty development of an
experimental system, were of several kinds. In the first place, so
large a growth had not been contemplated, and the extensions were
made more or less piecemeal, instead of being on a regular plan; the
location of the central station itself was very unfavorable, both as
regards the facilities for obtaining coal and other supplies; the cost
of water was excessive, and the amount available, inadequate.
This evil was partly remedied by elaborate arrangements for cooling
the injection water so that it could be repeatedly used, a device
costly and ineffective, and resulting in extravagant working, to say
nothing of the high charges made by the Paris company for supplying
water. To these drawbacks had to be added others of an even more
serious character. The engines first laid down were not economical,
and the compressors employed gave but a very inferior result; with
each extension of the plant, the efficiency of both engines and
compressors was increased, the most satisfactory, we believe, having
been those supplied by the Societe Cockerill, and one of which was
exhibited at the Paris exhibition in 1889. Still it was clearly
recognized that much better results were possible, results which
Professor Riedler claims have been attained and which will be embodied
in the new installation now in progress.
This central station is located on the left bank of the Seine, close
to the fortifications, opposite Vincennes and not far from the
terminal stations of the Orleans and the Paris, Lyons, and
Mediterranean Railways; the plan, Fig. 1, shows the position. The
works are separated from the river by the quay, over which a bridge
will be constructed for the transfer of coal from the landing stages
belonging to the company, into the works; as will be readily seen from
the plan, it would be quite easy to run junction lines to the two
adjacent railways, but with all the advantages given by water
carriage, it was considered unnecessary to incur the expense. The
river also affords a constant and unlimited water supply, so that none
of the difficulties existing at St. Fargeau Station in imperfect
condensation and cooling will be met with.
The new installation, called the Central Station of the Quai de la
Gare, is laid out on a very large scale, the total generating energy
provided for being no less than 24,000 horse power; of this it is
intended that 8,000 horse power will be in operation this year, and an
extension of 10,000 horsepower in 1892; the power now in course of
completion comprises four engines of 2,000 horse power each. Four
batteries of boilers will provide steam for these engines. Figs. 2, 3,
and 4 show the first section of the installation now in progress; the
four groups of engines (three-cylinder condensing) are shown at 1, 2,
3, and 4; the four groups of boilers ranged behind them at F, F; the
feed water heaters belonging to each group at V V.
[Illustration: COMPRESSED AIR STATION ON THE QUA DE LA GARE, PARIS.
(FIG. 2,3,4)]
The end of the building abuts against the Seine, and the position of
the water conduits for inlet and discharge are indicated at C and A
respectively. The installation, when completed, will include very
extensive arrangements for transporting and storing coal, and the
interior of the boiler houses will be furnished with an overhead
system of rails and carriers for handling the coal automatically, as
far as possible. All the principal mains and steam pipes are made in
duplicate, not only for greater security, but in order that each set
of engines and boilers may be connected interchangeably without delay.
The Seine supplies an ample quantity of water, but not in a condition
either for feeding the boilers, for condensation, or for the air
compressors.
[Illustration: THE NEW COMPRESSED AIR STATION AT PARIS. (FIG. 5, 6)]
Special provisions have therefore to be made to filter the water
efficiently before it is used. For this purpose the water is led to a
group of four filters (see L, Fig. 4); from them it passes into the
tanks, JJ, and is pumped into the heaters. The filters can be rapidly
and automatically cleaned by reversing the flow of water through them.
Figs. 5 and 6 show the general form of the type of engine adopted, as
well as the engine house, some of the mains, etc. They are vertical
triple-expansion engines, and are being constructed by MM. Schneider
et Cie, of Creusot, with a guarantee of coal consumption not to exceed
1.54 lb. per horse power per hour, with a penalty of 2,000 francs for
every 100 grammes in excess of this limit. It is evident that with
this restricted fuel consumption, a large margin for economy will
exist at the new works, as compared with the St. Fargeau station,
where the best engines cannot show anything like this result, while
some of the earlier ones are distinctly extravagant, and the whole
installation is handicapped with imperfect means of condensation.
Moreover, according to Professor Riedler, the consumption of steam by
the new Schneider engines will be only 5.3 kilos. per horse power and
per hour as compared with some of the large engines requiring 9
kilos., and the Cockerill engines--using 8 kilos. per hour, not to
speak of the older motors that are very extravagant in the use of
steam. The St. Fargeau station is worked under a further disadvantage.
The constantly increasing demand from subscribers taxes the resources
of the station to their fullest extent, so that practically there is
no reserve power.
In the new installation the work will be equally constant, but care
will be taken always to have a sufficient reserve. Electric lighting
will form a considerable part of the duty to be done from this
station, and in all cases it is intended to work with accumulators, so
that the resistance to be overcome by the engines, so far as this part
of the duty is concerned, will be well known and uniform. The
engineers of the Compressed Air Co., of Paris, have during the last
five years acquired an experience which could only be attained at a
high price and at the expense of a certain amount of failure; this
period, it is claimed, is now passed, and in the new installation it
is possible to put into practice all the valuable lessons learned at
St. Fargeau, to say nothing of the more favorable natural conditions
under which the extension is being started and the improvements in the
compression of the air made by Mr. Popp and Professor Riedler, and to
which we shall refer later.
Chiefly in consequence of the high value of the ground, vertical
engines were adopted at the new station; the proximity to the river
made the foundations somewhat costly, and the risk of occasional
floods rendered it desirable to set the level of the engine bedplates
20 inches above the floor of the building; the foundations of the
engines are continuous, but are quite independent of the building.
There are three compressing cylinders in each set of engines, one
being above each steam cylinder. Two of these are employed to compress
the air to about 30 lb. per square inch, after which it passes into a
receiver and is cooled; it is then admitted into the third or final
compressing cylinder and raised to the working pressure at which it
flows into the mains. In the illustrations, h, m, and b are the high,
intermediate, and low pressure cylinders of one set of engines; as
will be seen, each cylinder is on a separate frame connected by
girders; directly above the cylinders are the two low and the one high
pressure air cylinders, bı, mı, and hı respectively. The former
deliver the air compressed to the first stage into the receiver, Tı
(see Fig. 5), whence it passes into the third compression cylinder,
and thence by a main into the cylinders, R R, which are in direct
communication with the delivery mains; these mains terminate in the
subway, T. The water for condensation is brought into the engine house
by the channel, C, and the condenser pumps, a, draw direct from this
supply; the discharge main back to the river is shown at A. The
relative positions of the engine and boiler houses are indicated in
Figs. 2 to 5, where F shows the end of one group of boilers; the air
supply for the compressors is led from the central raised portion, S,
of the roof.
Professor Riedler's first experiments in improving the efficiency of
air compressors were made with one of the Cockerill compressors in use
at the St. Fargeau Station, and considerable difficulty attended this
work, because the machinery was necessarily kept almost in constant
operation. These compressors were designed by MM. Dubois and Francois,
of Seraing. Two of their leading features were the delivery of the
compressed air at as low a temperature as possible, and with a
relatively high piston speed of about 400 ft. a minute. The former
object is attained by the injection of a very fine water spray at each
end of the air cylinder, and its rapid removal with each stroke; the
free as well as the compressed air flows through the same passages,
one at each end of the cylinder; the inlet valves being placed at the
side of these passages, and the outlet or compressed air valves at the
top, the compressed air, entering a chamber above the cylinder, common
to both valves, and passing thence to the reservoir. The compressed
air valves, which are seven in. in diameter, are brought back sharply
to their seats at each stroke, by a small piston operated by
compressed air flowing through a by-pass from the chamber. The
illustrations published by us on page 686 of our forty-seventh volume
show the construction of these compressors. The engravings on page 683
of the same volume illustrate the compressors used in a somewhat older
part of the installation; they were made by M. Blanchod, of Vevey, and
a passing reference may be made to them. The air is admitted through
valves in the cylinder, and is forced out through spring-loaded
valves; water is admitted into the cylinder to cool the air.
Fig. 7 indicates the modification made by Professor Riedler in one of
the Cockerill compressors: a receiver, A, was placed under the two
compressing cylinders, B and C. The first stage is completed in the
large cylinder, B, the air being compressed to about 30 lb. per square
inch; from this it is discharged into the receiver, A, through the
pipe, Bı, where it meets with a spray injection that cools it to the
temperature of the water. The final stage is then effected in the
smaller cylinder, C, which, drawing the air from the receiver through
the pipe, Cı, compresses it to about 90 lb. and delivers it through
the pipe, d, to the mains. We hope shortly to publish drawings of this
compressor in its final form; in its elementary stage Professor
Riedler claims to have obtained some very remarkable results. He says
that the waste spaces in his modification were much smaller than in
the Cockerill compressor, while the efficiency of the apparatus was
largely increased. The actual engine duty per horse power and per hour
was raised, as a maximum, to 384 cubic feet of air at atmospheric
pressure, and compressed to 90 lb. per square inch, a marked increase
on the duty of the compressors in use at the St. Fargeau station. The
Cockerill compressors experimented on at the same time showed a
maximum duty of 306 cubic feet of air. A considerable advantage is
claimed in drawing clean and cool air from the outside of the
building, and beyond the main feature of carrying out the compression
in two stages, Mr. Riedler appears to have shown great skill in
introducing several minor alterations and improvements in the plant.
[Illustration: EFFICIENCY CURVES FOR THREE TYPES OF COMPRESSORS. (Fig.
8, 9, 10)]
Figs. 8, 9 and 10 are diagrams showing the comparative efficiency of
the three types of compressors at St. Fargeau--Fig. 10 being a diagram
of the Riedler compressor--and indicate the gain derived from the
intermediate cooling. The loss is shown to be only 12 per cent., as
compared with a loss of 43 per cent. in a large part of the plant, and
of 105 per cent. in the earlier compressors of the St. Gothard type.
The table given herewith contains a summary of trials made by
Professor Gutermuth, and are intended to show the comparative results
of an extended trial with three kinds of compressors at St. Fargeau.
PERFORMANCES OF COMPRESSORS AT THE ST. FARGEAU CENTRAL STATION.
--------------+-------+--------+------+-------+--------+--------+---------+
| R p | | E | | | | |
| e o e | Horse- | f |Amount |Quantity| Cubic | |
Compressors. | v f r | Power | f |of Air | of Air |Feet of |Final Air|
| o |Absorbed| i |Passing| Passing|Air per |Pressure.|
| l E m | by | c |through| through| Horse- | |
| u n i |Compres-| i | Inlet | Valves | Power | |
| t g n | sors. | e | Valves| per | and per| |
| i i u | | n | each | Hour. | Hour. | |
| o n t | | c |Revolu-| | | |
| n e e | | y | tion. | | | |
| s . | | . | | | | |
--------------+-------+--------+------+-------+--------+--------+---------+
| | | | cubic | cubic | |lb. per |
1. | | | | feet | feet | |sq. in. |
_Sturgeon_ | | | | | | | |
_Compressor_ | 37 | 302 | .87 | 41.67 | 91,507| 261.3 | 90 |
Diameter of | 37 | 258 | .87 | 38.13 | 84,650| 276.1 | 90 |
cylinder, | | | | | | | |
23.62 in. | | | | | | | |
and 21.66 in.;| | | | | | | |
stroke, | | | | | | | |
48.63 in. | | | | | | | |
| | | | | | | |
2. | | | | | | | |
_Cockerill_ | 40 | 337 | .83 | 46.61 | 111,864| 281.83 | 90 |
_Compressor._ | 45 | 353 | .83 | 46.61 | 125,844| 302.66 | 90 |
Diameter of | 40 | 342 | .88 | 49.43 | 118,632| 296.65 | 90 |
cylinder, | 46 | 377 | .85 | 48.02 | 132,534| 298.77 | 90 |
25.98 in.; | 38.67 | 324 | .89 | 50.14 | 116,434| 306.19 | 90 |
stroke, | 38.5 | 337 | .89 | 50.14 | 115,818| 294.18 | 90 |
47.24 in. | 38.6 | 329 | .91 | 50.84 | 117,740| 305.13 | 90 |
| | | | | | | |
| | | | | | | |
3. | | | | | | | |
_Riedler_ | 52 | 615 | .985 | 77.34 | 241,300| 353.50 | 90 |
_Compressor._ | 60 | 709 | .985 | 76.98 | 277,128| 353.50 | 90 |
Diameter of | 38 | 422 | .985 | 77.34 | 176,330| 376.12 | 90 |
low-pressure | 39 | 424 | .985 | 77.34 | 181,030| 384.60 | 90 |
cylinder, | | | | | | | |
42.91 in.; | | | | | | | |
diameter of | | | | | | | |
high-pressure | | | | | | | |
cylinder, | | | | | | | |
26.38 in.; | | | | | | | |
stroke, | | | | | | | |
47.24 in. | | | | | | | |
--------------+-------+--------+------+-------+--------+--------+---------+
The results thus obtained were so satisfactory that the designs were
prepared for the great compressors to be operated at the new central
station on the Quai de la Gare by the 2,000 horse power engines.
The transmission of the compressed air through the mains is
unavoidably attended with a certain percentage of loss, which, of
course, increases with the length of the transmission, the presence of
leakage at the joints, etc. Professor Riedler has devoted considerable
time to the investigation of this source of waste, and we shall
presently refer to the results he has recorded; in the first place,
however, we propose to consider what he has to say on the subject of
utilizing the air at the points of delivery, and the means employed
for obtaining a relatively high efficiency of the motor.
In the earliest stages of the Popp system in Paris it was recognized
that no good results could be obtained if the air were allowed to
expand direct into the motor; not only did the formation of ice due to
the expansion of the air rapidly accumulate and choke the exhaust, but
the percentage of useful work obtained, compared with that put into
the air at the central station, was so small as to render commercial
results hopeless. The practice of heating the air before admitting it
to the motor is quite old, but until a few years ago it never seems to
have been properly carried out; in several mining installations where
this motive power had been long used, more or less imperfect attempts
had been made to heat the air; in one instance only, recorded by
Professor Riedler, was an efficient means employed. In this case a
spray of boiling water was injected into the cylinder and mixed with
the air at each stroke, with the result that a very marked economy was
obtained.
After a number of experiments, Mr. Popp arrived at the conclusion that
the simplest mode of heating, if not the most efficient, was at all
events the most suitable, as it was a matter of the first importance
that subscribers should not be troubled with the charge of any
apparatus involving complication or careful management; he therefore
adopted a simple form of cast iron stove lined with fireclay, heated
either by a gas jet or by a small coke fire. It was found that this
apparatus, crude as it was, answered the desired purpose, until some
better arrangement was perfected, and the type was accordingly adopted
throughout the whole system. It was quite recognized that this method
still left much to be desired, and the economy resulting from the use
of an improved form was very marked.
From a large number of trials very carefully carried out by Professor
Gutermuth, it was found that more than 70 per cent. of the total
number of calories in the fuel employed was absorbed by the air and
transformed into useful work. Whether gas or coal be employed as the
fuel, the amount required is so small as to be scarcely worth
consideration; according to the experiments carried out, it does not
exceed 0.09 kilo. per horse power and per hour, but it is scarcely to
be expected that in regular practice this quantity is not largely
exceeded. Professor Weyrauch has also carefully investigated this part
of the subject and fully confirms, if he, indeed, does not go beyond
Professor Gutermuth. He claims that the efficiency of fuel consumed in
this way is six times greater than when burnt under a boiler to
generate steam. He goes so far as to assert that with a good method of
heating the air, not only can all the losses due to the production and
the transmission of the compressed air be made good, but also that it
will actually contain more useful energy at the motor than was
expended at the central station in compressing it.
According to Professor Riedler, from 15 to 20 per cent. above the
power at the central station can be obtained by means at the disposal
of the power users, and it has been shown by experiment that by
heating the air to 250 deg. Cent. an increased efficiency of 30 per
cent. can be obtained. Better results than those heretofore obtained
may, therefore, be confidently expected with a more perfect and
economical application of the fuel in heating the air, and a better
means of regulation in admitting it to the motors. In his report
Professor Riedler indicates a method by the use of which he considers
considerable advantages may be secured. This is the heating the air in
two stages instead of at one operation, and passing it through two
motors, to the first of which the air is admitted heated only to a
moderate extent; the exhaust from this motor then passes into a second
heater and thence into the second motor. A series of experiments with
this arrangement were recently carried out.
The consumption of air per brake horse power was reduced from 812
cubic feet per hour, a favorable duty in the single motor, to 720, and
in the best result to 646 cubic feet with the two motors and double
heaters. It should be added that these trials were carried out with
steam engines but ill adapted for the purpose. It is to be regretted
that the experiments of Professor Riedler could not have been
conducted with more perfect appliances, but it must be borne in mind
that the utilization of compressed air, especially as regards the
motors, is still in a very imperfect stage, and that a great deal
remains to be done before the maximum power available at the motor can
be obtained. Investigations in this direction for a considerable time
to come must be directed, therefore, toward improving the design and
construction of the motors and the treatment of the air at the point
of delivery into the engine.
A large number of motors in use among the subscribers to the
Compressed Air Company, of Paris, are rotary engines developing one
horse power and less, and these in the early times of the industry
were extravagant in their consumption, to a very high degree. To some
extent this condition of things has been improved, chiefly by the
addition of better regulating valves to control the air admission.
As altered, the two horse power rotary motors, when employed as cold
air engines, a method often desired in special industries, consume
1,059 cubic feet per hour and per indicated horse power; with a
moderate degree of heating, say to 50 deg. Cent., this consumption
falls to 847 cubic feet. The efficiency of this type of rotary motors
with air heated to 50 deg. may now be assumed at 43 per cent., not a
very economical result, it is true, and one that may be largely
improved, yet it is evident that with such an efficiency the use of
small motors in many industries becomes possible, while in cases where
it is necessary to have a constant supply of cold air, economy ceases
to be a matter of the first importance.
Some useful results were obtained with compressed air used in crank
engines; it is to be regretted that with this, also, apologies have to
be made for the imperfect design and construction; they were old steam
engines, some of those of two horse power losing from 25 to 30 per
cent. by their own friction; some of the others tried, however, were
far better, a newer type losing only from 8 to 10 per cent., while the
80 horse power referred to below showed an efficiency of 91 per cent.
From these trials Prof. Riedler deduces--assuming 85 per cent.
efficiency--a consumption of 611, 752, and 720 cubic feet per brake
horse power. It is very evident from the foregoing that the Compressed
Air Company, of Paris, will never do itself justice until as much
thought and care has been devoted to the economical use of the motive
power as has been expended in the means of producing it, and Professor
Riedler's recent investigations should be especially useful in this
respect. The question has indeed attracted the attention of more than
one manufacturer, and reference is made to a particular type of small
rotary motors which are being constructed by MM. Riedinger & Co., and
which is stated have given very excellent results. These engines were
specially used for working sewing machines and developed on the brake
an efficiency of 34.07 and 51.63 foot pounds per second. Trials were
made with a half horse power variable expansion Riedinger engine.
TRIALS OF A SMALL ROTARY RIEDINGER ENGINE.
______________________________________________________________
| |
Number of trials. | I. | II.
______________________________________________|_______|_______
| |
Initial air pressure. lb. per square inch | 86 | 71.8
" temperature. deg. Cent. | +12 | +170
Ft. pounds per second measured on the brake. | 51.63 | 34.07
Revolutions per minute. | 384 | 300
Consumption of air for one horse power per | |
hour. | 1,377 | 988
______________________________________________|_______|_______
TRIALS OF A 0.5 HORSE POWER RIEDINGER ROTARY ENGINE.
_____________________________________________________________________
| | | |
Number of trials. | I. | II. | III. | IV.
__________________________________________|______|______|______|_____
| | | |
Initial pressure of air. lb. per sq. in. | 54 | 69.7 | 85 | 71.8
" temperature of air. deg. Cent. | 170 | 180 | 198 | 8
Final " " " | 25 | 20 | ... | 25
Revolutions per minute. | 335 | 350 | 310 | 243
Foot pounds per second measured on | | | |
brake. | 271 | 477 | 376 | 316
Consumption of air per horse power | | | |
and per hour. | 883 | 791 | 900 |1,148
__________________________________________|______|______|______|______
TRIAL OF AN 80 HORSE POWER (NOMINAL) FARCOT STEAM ENGINE.
___________________________________________________________________
| R p | | |
| e e | I | | Consumption of
| v r | n | Temperature | air per horse
| o | d h p| of air. | power and per
| l m | i o o| | hour.
| u i | c r w|__________________|________________
| t n | a s e| | | |
Motor. | i u | t e r|Admission|Exhaust.|Nominal| Brake
| o t | e .| | | horse | horse
| n e | d | | | power.| power.
_________________|_s_.__|______|_________|________|_______|________
| | | deg. C | deg. C | |
Nominal 80 horse | 54.3 | 72.3 | 129 | 21 | 469 | 517
power single | 54.3 | 72.3 | 152 | 29 | 437 | 475
cylinder Farcot | 54.0 | 72.3 | 160 | 35 | 424 | 465
engine. | 40 | 65.0 | 170 | 49 | 438 | 477
_________________|______|______|_________|________|_______|________
These motors, it may be assumed, represent the best practice that has
been obtained up to the present time in the construction of compressed
air motors; with the smallest of them, indicating about one-tenth of a
horse power, the consumption of air, when admitted cold, was 1377
cubic feet and 988 cubic feet when the air was heated before
admission. The half horse power engine consumed 1148 cubic feet of
cold air, and of heated air 791 cubic feet per horse power and per
hour. It should be mentioned that these, the most valuable and
suggestive of all the trials carried out by Professor Riedler, were
conducted with the greatest care, two distinct modes of measuring the
air supplied being followed on two occasions for each test; it may
therefore be considered that the results given are absolutely correct.
The trials were made with an old single cylinder Farcot engine,
nominally of 80 horse power, but indicating over 72.3. With this
engine the consumption of air varied from 465 to 517 cubic feet, the
larger consumption being due to the lower temperature (129 deg. Cent.)
to which the air was raised before admission; in the most economical
result the temperature was 160 deg. Cent. The volumes of air referred
to are, of course, in all cases taken at atmospheric pressure.
Among the important losses that have to be reckoned with in every
system of distributing motive power from a central station--whether by
steam or by electricity, water, or compressed air--losses must occur
in the mains by which the power generated is transferred from the
point of production to that of consumption. In the case we are now
considering very careful tests were conducted in 1889 by Professor
Kennedy, to whose report we have already referred. Since that time
important changes have been made by the Compressed Air Company, at
Paris, in the details of distribution, and on this account the later
investigations of Professor Riedler on the losses due to this cause
are of special interest.
Before its admission into the mains a certain loss occurs at the St.
Fargeau station, in the large reservoirs to which the air is delivered
from the compressors. This question of preliminary storage was one
that received considerable attention when the designs of the new
station on the Quai de la Gare were being considered. It was intended
to construct very large receivers in the basement of the station, and
the foundations for these were even commenced. It was decided,
however, that for the 10,000 horse power which is to form the first
section of the new station, and for which the complete system of mains
has already been laid down, storage reservoirs would be unnecessary,
and a saving both in first cost and subsequent loss of air would be
effected. The length of mains of 19.69 in. diameter is so considerable
that they will contain at all times a sufficient reserve of air to
prevent any irregularities in pressure at the motors.
With reference to these mains it may be mentioned that, unlike the
11.81 in. conductors of the St. Fargeau system, of which 17 kilometers
are laid in the Paris subways, the new mains are entirely laid in the
streets, it having been found impossible to make room for these large
pipes in the subways already crowded with telegraph and telephone
wires, water mains, etc.
Professor Riedler investigated the two causes of loss in the
mains--leakage and resistance. It was superficially evident that the
mains of the old system were so well laid, and the joints so well
designed, that the loss from leakage was never a serious one. In
order, however, to ascertain the amount accurately, a series of
careful experiments were carried out by Professor Gutermuth with the
11.81 in. mains of the St. Fargeau system.
EXPERIMENTS ON LEAKAGE IN MAINS.
---------------------------------------------------------------------
| | | | | | L P A |
| | | | Air Pressure | Loss of | o e i |
| | | | in Mains. | Pressure. | s r r |
| | | |---------------|-------------| s |
| | | | B | | | | C D |
| |System of Mains | Length. | e T| | | | o e e |
|N| Tried. | | g r| At | | | f n l |
|u| | |A i o i| End |During| Per | t i |
|m| | |t n f a| of |Trials|Hour. | A . v |
|b| | | n l|Trials.| | | i e |
|e| | | i s| | | | r o r |
|r| | | n .| | | | f e |
| | | | g | | | | d |
--+-----------------+---------+-------+-------+------+------+-------|
| | | yards. | atm. | atm. | | | |
|1|Southern reseau | | | | | | |
| | to Place de la | | | | | | |
| | Concorde. | 9,980 | 6.5 | 6.0 | 0.5 | 1.5 | 3 |
|2| Total reseau | 18,500 | 6.9 | 5.9 | 1.0 | 1.5 | 6.3 |
|3|To Place de | | | | | | |
| | la Concorde | 9,980 | 7.0 | 6.43 | 0.57 | 0.75 | 2.16 |
|4|Total reseau | 18,500 | 6.7 | 5.28 | 0.88 | 1.32 | 5.5 |
|5|Northern reseau | | | | | | |
| | to Rue de Belle-| | | | | | |
| | ville. | 1,530 | 6.0 | 5.0 | 1.0 | 0.6 | 2.3 |
|6|To the Rue des | | | | | | |
| | Pyrenees. | 600 | 6.1 | 3.7 | 2.4 | 0.56 | 2.2 |
---------------------------------------------------------------------
These trials refer to the mains running from the St. Fargeau station
to the Place de la Concorde, a length of 9.142 kilometers; to the
whole system of mains, 16.5 kilometers; to the northern mains running
from St. Fargeau to the Rue de Belleville, 1.4 kilometers; and from
St. Fargeau to the Rue des Pyrenees, 6.5 kilometers. It will be seen
from the figures given in the table that the actual loss is small, and
it is stated that this is due chiefly to the elastic joint employed
throughout the system, excepting in the Rue de Belleville, where rigid
couplings are used, and continual trouble is experienced from loss by
leakage. In all cases the losses given are the maximum, which only
occur under the most unfavorable conditions.
It was found, during the first, second, and fourth tests, that
considerable leakage occurred between the St. Fargeau central station
and the Rue de Belleville. During the trials two and four, an
uncertain amount of loss occurred from the consumption of air required
to work the pneumatic clocks, and also motors in the circuit, that
could not be stopped. The tests two and four include all losses in the
service pipes, as well as the mains.
The production of compressed air at the central station is assumed at
30,000 cubic feet per hour (atmospheric pressure), and in all cases
the loss in the mains is taken as a percentage of the total
production.
The losses due to resistance in the mains were also examined with
great care, over independent sections, as well as through the complete
_reseau_. During the early part of these trials, an unusual and
excessive loss was recorded, the cause of which could not be at first
ascertained. At intervals along these mains are placed a number of
water reservoirs which receive the water injected into the mains; in
addition to these the direct flow of the air is interrupted by
numerous siphons, the stop valves to branches, etc. Investigation
showed that the presence of these reservoirs created considerable
resistance on account of an increased and subsequently reduced
section. The exact loss from this cause was, therefore, carefully
measured, as well as the losses existing in the mains not so
interrupted. The results show that the loss by expansion at one
reservoir, when the speed of the air flow was 23 ft. per second, was
equal to 0.15 atmosphere; with a speed of 29 ft. 6 in. per second, it
amounted to 0.2 atmosphere.
Therefore, the presence of five such reservoirs would cause a loss in
pressure equal to one atmosphere. This very undesirable arrangement is
not repeated in the new system, the sumphs being connected in such a
way as not to modify the section of the tube, nor consequently the
pressure of the air. The presence of the siphons and stop valves did
not seem to affect the pressure to any measurable extent. The
following table contains a list of the more important mains tested,
and it may be mentioned that the resistance, due to the reservoirs,
was at first partially included. The trials were carried out while the
mains were not being drawn upon by subscribers.
-----------------------------------------------------------------------
| |
Section of Mains Tested. | Length. |No. of
| |Tests.
| |
---------------------------------------------------+------------+------
| yards. |
From the central station to the end of reseau and | |
back to central station by return circuit | 18,100 | 7
From the central station to the Rue Fontaine au |\ 14,600 |/ 3
Roi |/ 9,900 |\ 4
From the central station to the Rue de la | |
Charonne | 9,490 | 5
From the Rue de la Charonne to Fontaine au | |
Roi | 4,770 | 3
From the central station to the Avenue de la | |
Republique | 1,860 | 8
Various trials on different lengths of mains |770 to 8,000| 11
-----------------------------------------------------------------------
Over the whole system of 16.5 kilometers, which was also tested when
no air was being taken off, there were four reservoirs of considerable
size, and which offered a large resistance with a corresponding loss
of pressure; on the line there were also 23 siphons and 42 stop
valves.
These trials were repeated several times to secure accuracy, and the
speed of the air was brought to 49 ft. a second. The results obtained
in one of these trials may be taken as an example. The main between
the Rue St. Fargeau and the Fontaine au Roi, on which there are no
collecting reservoirs, but three siphons and eight stop valves, gave,
with an average speed of 21 ft. 3 in., a loss in pressure of 0.05
atmosphere for each kilometer of main.
From these experiments it would appear that, assuming a speed of 21
ft. per second, a loss in pressure of one atmosphere would correspond
to a distance of 20 kilometers; that is to say, a central station
could extend its mains on all sides with a radius of 20 kilometers,
and the motors at the ends of the lines would receive the air at a
pressure 15 lb. less than at the central station. Professor Riedler
states that as an actually measured result, the velocity of the air
through the mains of the St. Fargeau system is 19 ft. 8 in. per
second, and that the loss in pressure per kilometer is 0.07
atmosphere. From this it follows that including the resistances due to
the four reservoirs, and other obstructions actually existing, an
allowance of one atmosphere loss on a 14 kilometer radius is ample. By
increasing the initial pressure of the air, much better results can be
obtained, and future attention in practice should be devoted to this
point. The amount of work required to compress air does not increase
in the same ratio as the pressure, and for this reason considerable
economy can be effected at the first stage, and the loss in the mains
will be reduced.
Passing to another point of the same subject, Professor Riedler
considers the best dimensions that should be given to the mains.
Resistance decreases with an increase in the diameter of these and in
direct ratio to their diameter; for this reason--still assuming a
pressure corresponding to a velocity of 20 ft. per second--with a fall
of one atmosphere, a length of 40 kilometers could be succesfully
worked.
The mains of the new _reseau_ for the Quai de la Gare station are
19.69 in. in diameter; they are built up of steel plates riveted, and
this Professor Riedler considers to have been a serious error on
account of the extra resistance offered by the large number of rivet
heads.
The following may be taken as a brief summary of Professor Riedler's
conclusions: Recent improvements in central station practice have
resulted in an increased efficiency of about 30 per cent. in the
compressors, but this benefit can only be realized when the new
station is in operation. That the small and very imperfect air engines
in use on the system give an efficiency of 50 per cent., while with
ordinary steam engines driven by air an efficiency of 80 per cent. can
be reached with a very small expenditure of fuel for heating the air
before admitting it into the motor. That special attention should be
given to the improvement of air engines, and that with increased
initial pressures at the central station the distance of the
transmission can be very considerably augmented. Finally, Professor
Riedler claims that power can be transmitted by compressed air more
conveniently and more economically than by any other means.
* * * * *
[Continued from SUPPLEMENT, No. 802, page 12810.]
THE BUILDERS OF THE STEAM ENGINE--THE FOUNDERS OF MODERN INDUSTRIES
AND NATIONS.[1]
[Footnote 1: An address delivered at the Centennial Celebration of the
American Patent System, Washington, April, 1891.]
By Dr. R.H. THURSTON, Director of Sibley College, Cornell University.
Papin, Worcester, Savery, were the authors of the period of
application of the power of steam to useful work in our later days.
The world was, in their time, just waking into a new life under the
stimulus of a new freedom that, from the time of Shakespeare, of
Newton, and of Gilbert, the physicist, has steadily become wider,
higher, and more fruitful year by year. All the modern sciences and
all the modern arts had their reawakening with the seventeenth
century. Every aspect of freedom for humanity came into view in those
days of a new birth. Both the possibility of the introduction of new
sciences and of new arts and the power of utilizing all new
intellectual and physical forces came together. The steam engine could
not earlier have taken form, and, taking form, it could not have
promoted the advance of civilization in the earlier centuries. The
invention becoming possible of development and application, the
promotion of the arts and of all forms of human activity became a
possible consequence of its final successful introduction into the
rude arts that it was to so effectively promote and improve.
But the work of these inventors was in itself but little more
important than that of the Greek inventor of the steam aelopile, for
each brought forward a machine which was, from a business point of
view, utterly impracticable, and which, in each case, only served to
show that a better device might prove useful and lead the way to its
introduction. The merit of the inventors of the eighteenth century was
that they were _able_ to lead the way, to point out the path to
success, to furnish evidence of the value of the coming, crowning
invention. The "fire engines," as they were then called, of these now
famous men were merely contrivances by the use of which the pressure
of confined steam of high tension could be brought to act on the
surface of a mass of confined water, forcing it downward into pipes
through which it was led off and upward to a higher level; and thus a
mine could be drained, ineffectively and expensively to be sure, but
vastly more satisfactorily than by the animal power of the time. The
machine of Savery was the best of all; but that was only a somewhat
improved and manageable rearrangement of the engines of Papin and
Worcester. And, after all, Papin, the greatest man of science perhaps
of his time, died in poverty; Worcester languished in prison his whole
life, and the later efforts of his widow brought nothing by way of a
return for his invention; nor did either they or their successor,
Morland, make the introduction of the engine either general or
remunerative.
Savery, coming on the stage at more nearly the right time to seize
upon an opportunity, gained more than either of his predecessors; but
we have no evidence that he ever acquired any large compensation or
met with any remarkable business success in the introduction of the
rude engine which bore his name; nor did Desaguliers, the great
philosopher, or even Smeaton, the great engineer, of the later years
of that century, make any great success of it. It was reserved for
Watt to reap the harvest. But, though he so effectively reaped where
his predecessors had sown, Watt is not the greatest of the inventors
of the steam engine, if we rate his standing by the magnitude of the
improvement which marked his reconstruction of the engine.
It was NEWCOMEN who made the modern steam engine.
When Newcomen came forward the labors of Worcester in Great Britain
had sufficed to attract the attention of all intelligent men to the
character of the problem to be solved, and to convince them of its
importance and promise. The work of Savery had shown the
practicability of the solution of the problem, both in mechanics and
finance. He succeeded, though under great disadvantages and
comparatively inefficiently. Once the task had been performed, though
ever so rudely, the rest came easily and promptly. The defects of the
Savery system were at once recognized; its great wastes of heat and of
steam were noted, and the fact that they were inherent in the system
itself was perceived. A complete change of type of machine was
obviously requisite; it was this which constituted the greatest
invention in the whole history of the steam engine, from Hero's time
to our own; and to Newcomen we owe more than to any other man who ever
lived, the value of the invention itself being considered, and the
importance of the services of its introducer being left out of
consideration. No such complete and vital improvement and modification
of the machine has ever been effected by any other man, Watt and
Corliss not excepted. Newcomen and his comrade Calley--we do not know
how the honors should be divided--produced the modern steam engine.
Its predecessor, the Savery engine, had been a mere steam "squirt."
Newcomen constructed an engine. Savery built a simple combination of
cylindrical or ellipsoidal vessels which wastefully and at once
performed all the several offices of engine, pump, condenser, and
boiler; Newcomen divided the several elements among as many parts,
each especially adapted to the performance of its task in the most
effective manner--the condenser excepted; for that was Watt's
principal invention--and thus produced the first steam engine in the
modern sense of that term.
It was Newcomen, not Watt, who gave us the train of mechanism that we
now call the steam engine. It is to Newcomen, rather than Watt, that
we owe the highest honors as an inventor in this series of the most
important of all the products of the inventive genius of mankind.
Newcomen brought into existence a new, the modern, type of engine, and
effected the greatest revolution that has been recorded in the history
of the arts. Without Newcomen, there might have been no Watt; without
Watt, there very possibly may not even yet have been brought into
existence that giant of our time, whose mighty powers are employed
more effectively than ever those of Aladdin's genii, in building
palaces, in transporting men and material, in doing the work of the
whole world; promoting the welfare of the race, in a single century,
more than had all the forces of matter and mind together in the whole
previous history of the world. Newcomen laid down a foundation beneath
our whole economic system, out of sight, almost, but the essential
base, nevertheless, on which Watt and his successors have carried up
the great superstructure which seems to us to-day so imposing; which
is so tremendous in magnitude, importance, and result. If to any one
man could be assigned the credit, it is Newcomen who is to be
considered the inventor of the steam engine.
James Watt, indisputably the great inventor that he was, found the
steam engine ready to his hand, applied himself to its improvement,
and made it substantially what it is to-day. His most important work,
the most unique service performed by him, was, however, that of its
adaptation and introduction to do the work of the world. James Watt
was the inaugurator of the era of refinement of the machine already
invented, and the greatest of its builders and distributors. His
inventions were all directed to the improvement of its details, and
his labors to its introduction and its application to the myriad tasks
awaiting it. By the hands of Watt it was made to pump water, to spin,
to weave, to drive every mill; and he it was who gave it the form
demanded by Stephenson, by Fulton, by the whole industrial world, for
use on railway and steamboat, and in mill and factory, throughout the
civilized countries of the globe. It was this great mechanic who
showed how it might be made to do its work with least expense, with
highest efficiency, with greatest regularity, with utmost
concentration of power.
The grand secret of his success was historical and economic, as much
as scientific and mechanical. He brought out his inventions just when
the world was economically and historically ready for them. The age of
authority was past, that of freedom was come; the period of political
and ecclesiastical tyranny was gone by, and that of the spontaneous
development of man was arrived. The great invention was offered to a
world ready and needing it, and, more than all, competent, for the
first time in history, to make and use it.
James Watt was himself a product of the modern scientific spirit. He
was a man so constituted mentally that he could apply scientific
methods to problems which his logical and clairvoyant mind could
readily and exactly formulate the instant he was led to their
consideration in the natural course of his progress. He was the ideal
great inventor and mechanic. With inventive genius he combined strong
common sense--not always a quality distinguishing the inventor--clear
perception, breadth of view, and scientific method and spirit in the
treatment of every question. His natural talent was re-enforced by an
experience and an environment which led him to develop these ways and
this mental habit. His trade was that of an instrument maker, his
position was that of custodian and repairer of the apparatus of
Glasgow University. He had for his daily companions and stimulus the
great men and ozonized atmosphere of that famous institution. He kept
pace with advancing science, and was imbued, both naturally and
through contact with its promoters, with that ambition and those
aspirations which are the life element of all progress, whether
scientific or other. He was aware of the nature of the problems
seeking solution at the time, and familiar with the state of his own
art and that of the great mechanicians about him. Everything was
favorable to his progress, so soon as he should be given an
opportunity to take a step in advance and to come into sight at the
front. The man and the time were both ready, and all conditions,
internal and external, social and personal, were favorable to his
development.
The invention upon which Watt was to improve was at his hand. A word
in regard to its status at the moment will throw some light upon that
of Watt and his creation. Newcomen had, as we have seen, produced the
modern type of steam engine as an original and wholly novel invention.
But this machine, marvelous as an advance upon pre-existing forms of
the steam engine, was still, as seen in the light of recent knowledge
and experience, exceedingly defective. The purpose of a steam engine
is to convert into usefully applicable power the hidden energy of
fuel, stored ages ago in the earth, by transformation, through the
action of vegetation, from the original form, the heat of the sun,
into an available form for reconversion, through thermodynamic
operations. In this process of reconversion, whatever the nature of
the machine used in the operation, there are invariably wastes, both
of heat required for conversion into power and of the power thus
produced. That machine which effects the most complete transmutation
of the heat supplied it into mechanical power, which wastes the least
amount of heat supplied and of power produced, is the best engine, and
constitutes an advance over every other.
It was this reduction of wastes that made the Newcomen engine so much
superior to that of Savery. The latter was by far the simpler and less
costly construction; but its enormous losses, both of heat and of
power, mainly the former, however, made it an extravagant expenditure
of money to buy and use it. The Newcomen engine, costly and cumbrous,
comparatively, nevertheless wasted so much less heat and steam and
fuel that no one could afford to buy the cheaper machine. Before
considering what Watt accomplished, we may find it profitable to
examine into the nature of the wastes which characterized this later
and better machine on which he effected his improvements.
The Newcomen engine consisted of a steam boiler, a steam cylinder, a
beam and a set of pumps. By making the boiler do its work separately,
the engine acting independently, and the pumps as a detached portion
of the mechanism, this inventor had reduced to an enormous extent
those wastes of heat and of steam and of fuel which were unavoidable
in the older machines in which all these parts were represented by a
single vessel, or by two at most, in each element. In the Savery
engine, the steam entering first heated up the interior of the working
vessel to its own temperature, and held it at that temperature in
spite of the cooling influence of the water present. This consumed
large quantities of heat. It then was compelled to surrender probably
much greater quantities still to the water itself, coming in direct
contact as it did with its surface. If the water was agitated, either
by the currents produced during its ingress or by the impact of the
steam entering the vessel, this heating action penetrated to
considerable depths and perhaps even warmed the whole mass very far
above its initial temperature. This constituted another and a very
serious loss. Then, again, as the water was gradually driven out of
the containing vessel by the steam pressing on its surface, new
portions of the vessel and new masses of water were continually
brought in contact with the hot steam, taking its full temperature,
and thus, often, probably, finally heating the whole mass of the
forcing vessel, and a large proportion of the water as well, up to the
temperature, approximately at least, of the steam itself. Thus in many
instances, if not always, vastly more heat and steam were wasted, in
this undesirable heating of water and forcing vessel, than were
usefully employed in the legitimate work of raising the water to a
higher level. In fact, in some cases in which these quantities were
measured, the wastes were one hundred times as much as the work done.
One per cent. of the heat supplied did the work; while ninety-nine per
cent. was thrown away. One dollar or one shilling expended for fuel to
do the work was accompanied by an expenditure of ninety-nine dollars
or shillings thrown away, because of the imperfections of the system
and machine. The whole history of the development of the steam engine
has been one of gradual reduction of these wastes; until to-day, our
best engines only compel us to spend five dollars for wastes to each
dollar paid out for useful work. A business man would think that amply
extravagant, however, and the man of science is continually seeking
methods of evading these losses, a large proportion of which are now
apparently unavoidable in heat engines, by finding some new system of
heat and energy transformation.
Watt was the instrument maker and repairer at Glasgow University in
the year 1763. His companions were, among others, the professors of
natural philosophy and of mathematics in the university. Their
conversation and their frequent presentation of practical and
scientific questions and problems stimulated his naturally inquiring
and inventive mind to the pursuit of a thousand interesting and
promising schemes for the improvement of existing methods and
machinery. Dr. Robison, then a student, suggested the invention of a
steam carriage for use on common roads, and the young mechanician at
once began experiments that, resulting in nothing at the time, were
nevertheless continued, in one or another form, until all modern
applications of steam came into view. Dr. Black taught Watt chemistry,
then a newly constructed science, and led him on to the discovery,
finally made by them independently, of the fact and the magnitude of
the latent heat of steam; the discovery coming of a series of
scientifically planned and accurately conducted investigations, such
as the man of science of to-day would deem creditable. The treatises
of Desaguliers and others on physics gave Watt a knowledge of that
domain of natural phenomena which stood him in good stead later, when
he attempted to apply its principles to the reduction of the wastes of
the steam engine.
It was while at Glasgow University, working under such influences and
in such an atmosphere of intellectual activity, that the accident of
the Newcomen model engine needing repair brought to the mind of Watt
the opportunity which, availed of at once, made him famous and gave
the world its greatest aid, its most powerful servant. The observing
mind of the great mechanic immediately noted its defects, sought their
causes, found their remedy. He discovered, at once, that the quantity
of steam entering the cylinder of the little engine has four times the
volume of the cylinder receiving it: in other words, three-fourths of
that steam must be condensed immediately on entrance. This meant,
evidently, that only one-fourth of the steam supplied was utilized,
and even then inefficiently, in doing its work. The reason of this was
as easily seen, immediately the fact was revealed. As Watt himself
expressed it, the causes of this loss, causes which would obviously be
exaggerated in a small engine, were: "First, the dissipation of heat
by the cylinder itself, which was of brass and both a good conductor
and a good radiator. Secondly, the loss of heat consequent upon the
necessity of cooling down the cylinder at every stroke in producing
the vacuum. Thirdly, the loss of power due to the pressure of vapor
beneath the piston, which was a consequence of the imperfect method of
condensation." This much determined, the next step looked toward the
confirmation of his conclusions and the remedy of the defects.
To meet the first difficulty he made a cylinder of wood, soaked in oil
and baked, a non-conducting and non-radiating material. Then he was
able to determine with some accuracy the quantities of steam and
injection water used in the engine; and a comparison with the original
cylinder and its operation showed that not only four times the
quantity of steam, but also four times the amount of injection water
was used as was necessary, assuming wastes checked. Further scientific
research on the part of Watt gave him measures of specific heats of
the metals and of wood, the specific volumes of steam at various
working pressures, the evaporative efficiency of boilers, the
pressures and temperatures of steam in the boiler under specified
conditions, the quantities of steam and of water required for the
operation of his little condensing engine.
Then came his enunciation of the grand principle of economy in the
construction and operation of the steam engine: "Keep the cylinder as
hot as the steam which enters it," as he expressed it. This was Watt's
guiding principle, as it has been that of all his successors in the
improvement of the economic performance of the steam engine and of all
other heat engines. The great source of waste is the dispersion of
heat, uselessly, which should be applied to the production of work by
its transformation, thermodynamically, into the latter form of energy.
The second form of waste is that of power thus produced in the
unprofitable work of moving the parts of the engine itself; and the
third is that of heat by transfer, without transformation, by
conduction and radiation to surrounding bodies. In modern engines, the
latter is but three or five per cent., in the best cases; the second
waste constitutes perhaps ten per cent.; while the first of these
losses amounts very usually to seventy per cent., of which last
one-third or one-fourth is of the kind discovered by Watt, the rest
being the thermodynamic waste incident to all known methods of
operation of heat engines, and apparently unavoidable. In our very
best and largest engines, the waste found by Watt to constitute three
fourths of all heat supplied has been brought down to ten per cent., a
fact which well exemplifies the advances made since his time of
apprenticeship by himself and his successors of this nineteenth
century. The steam engine of to-day, in its most successful operation,
gives us twenty-five times as much power from a pound of coal as did
the engine that the great inventor sought to improve: this is the
magnificent fruit of that one discovery of James Watt, and of
application of the simple principle which he so concisely and clearly
stated.
The method adopted by Watt to secure a remedy, so far as practicable,
of this defect of the older machine was as simple and as perfect as
was the principle which it embodied. He first removed from the
cylinder the prime source of its wastes; providing a separate
condenser, and thus avoiding the repeated chilling of its surfaces by
the cold water used in condensing the steam at exhaust, and also
permitting its strokes to be made with far greater frequency, thus
giving less time for cooling by the influence of the remaining vapors
after condensation. He next went still further, and provided the
cylinder with a closed top, keeping out the air, and a "jacket" of hot
boiler steam to _keep_ it as hot as the steam which entered it. These
were the two great improvements which converted the first real steam
engine into an economical form of heat engine and essentially finished
the work so grandly begun by Newcomen and Calley. These changes gave
us the modern steam engine; and these are Watt's first and greatest,
but by no means only, contributions to the production of the modern
world with all its comforts, its luxuries and its opportunities for
material, intellectual and moral advancement of individual and of
race. His work was to this extent complete in 1765.
But Watt did not stop here. There still remained for him the no less
important and the, in some senses, still more imposing, work of
finding employment for the new servant of mankind and of setting it at
its work of giving the human arm a thousand times greater strength, to
the mind of man uncounted opportunities to promote the advancement of
knowledge, of civilization, of every good of the race. His was still
the task of adapting the new machine to all the purposes of modern
industry. It had been hitherto confined to the task of raising water
from the depths of the mine; it was now to be harnessed to the railway
train; to be made to drive the machinery of the mill, to apply its
marvelous power to the impulsion of the river boat and ocean steamer;
to furnish energy, through endless systems of transfer and use, to
every kind of work that man could devise and should invent. All this
meant the giving of the machine forms as various as the purposes to
which it was to be devoted. It had previously only raised and
depressed a rod; it must now turn a shaft. It had then only operated a
pump; it must now turn a mill, grind our grain, spin our threads,
weave our cloths, drive our shops and factories, supply the powerful
blast of the iron furnace. It must be made to move with the utmost
conceivable regularity, and must, with all this, do its work in the
development of the hidden energy of the fuel, with the greatest
possible economy, through the expansion of its steam. All this was
achieved by James Watt.
The invention of the double-acting engine, in which the impulsion of
the steam is felt both in driving the piston forward and in forcing it
backward, both upward and downward, the application of its force
through crank and fly wheel, the creation of an automatic system of
governing its speed, and the discovery of the economy due to its
complete expansion, were all improvements of the first magnitude, and
of the greatest practical importance; and all these were in rapid
succession brought into existence by the creative mind that had
apparently been brought into the world for the express purpose of
giving to the hand of man this mighty agent, to perfect the mightiest
power that mind of man has yet conceived.
But to do the rest required more than inventive genius and mechanical
skill. It demanded capital and the stored energy of labor and genius
in other fields, directed by the mind of a great "captain of
industry." This came to Watt through Matthew Boulton, a manufacturer
of Birmingham, whose father and ancestors had gradually and
toilsomely, as always, accumulated the property needed for the
prosecution of a great business. The combination of genius and capital
is always an essential to success in such cases; and good fortune, a
Providence, we may well say, brought together the genius and the
capitalist to do their work, hand in hand, of providing the world with
the steam engine. Hand in hand they worked, and all the world to-day,
and the race throughout its future life, must testify gratitude for
the inexpressible obligations under which these two men have placed
them, doing the work of the world.
Boulton & Watt, the capitalist with the inventor, gave the world the
steam engine, finally, in such form and in such numbers that its
permanent establishment as the servant of man was insured. The
capitalist was as essential an element of success as was the inventor,
and, in this instance, as in a thousand others, the race is indebted
to that much-abused friend of the race, the capitalist, for much that
it enjoys of all that it desires. The industry and patience, the skill
and the wisdom required for the accumulation of this energy stored for
future use in great enterprises is as important, as essential, as
inventive power or any other form of genius. Talent and genius must
always aid each other. This firm was established in 1764 and its main
resources, aside from the bank account, were Watt's patent, about
expiring, and Watt's genius, and Boulton's talent as a man of
business. The patent was extended for twenty-four years, the new
inventions of Watt, now beginning to pour from his prolific brain in a
wonderful stream, were also patented, and the whole works were soon
employed upon the construction of engines for which numerous orders
soon began to pour in upon the now prosperous builders. The patent law
established Boulton and Watt and the firm paid back the nation with
handsome usury, giving it unimaginable profits indirectly through its
control of the work of the world and large profits directly through
the business brought them from all parts of the then civilized globe.
There has never, in the history of the world, been a more impressive
illustration of the value to a nation of that generous public policy,
that simply just legislation, which gives to the man of brain control
of the products of his mind. For a hundred years, Great Britain has,
largely through her encouragement of the inventor and her protection
of his mental property by securing the fruits of his labors, in fair
portion, to him, gained the power of dictating to the world and has
gained an advance that cannot be measured. Watt and Arkwright and
Stephenson and Crompton and their ilk, protected by their government
and its patent laws, made their country the peaceful conqueror of the
world. The story of the work of the inventor is a poem of mighty
meaning and of wonderful deeds. The inventor proved himself a mightier
magician than ever the world had seen.
"A creature he called to wait on his will,
Half iron, half vapor--a dread to behold;
Which evermore panted, and evermore rolled,
And uttered his words a millionfold."
Such was the outcome of this grand modern "trust," a combination of
the wisest legislation, the most brilliant invention, and the most
wisely applied capital. There are "trusts" of which the outcome is
most beneficent.
Since the days of Watt, the improvement of the steam engine and the
work of inventors has been confined to matters of detail. All the
fundamental principles were developed by Watt and his predecessors and
contemporaries and it only was left to his successors to find the best
ways of carrying them into effect. But these matters of detail have
been found to involve opportunities to make enormous strides in the
direction of securing improved efficiency of the machine. The further
application of the principle which led Watt to his greatest
inventions; of the principle, keep the cylinder as hot as the steam
which enters it, of that which he enunciated relative to the advantage
of expanding steam, and of that affecting the regulation of the
machine; have reduced the costs of steam and of fuel to a small
fraction of their earlier magnitude. One ton of engine to-day does the
work of eight or ten in the time of Watt: one pound of fuel or of
steam gives to-day ten times the power then obtained from it. A
steamship now crosses the Atlantic in one-eighth the time required by
the famous "liner" of the "Black Ball Line." The wastes of the engine
have been brought down from above eighty per cent. to eight; and a
half-ounce of fuel on board ship will now transport a ton of cargo
over a mile of ocean.
FREDERICK E. SICKELS gave us the first practicable form of expansion
gear in 1841; GEORGE H. CORLISS gave a new type of engine of marvelous
perfection and economy in 1849; Noble T. Green, Wm. Wright and many
less well known but no less meritorious inventors have since done
their part in the transformation of the old engine of Watt into the
modern wonder of concentrated and economical power, and marvel of
accurate and beautiful design and workmanship. The "trip cut-off,"
with reduced clearances, increased boiler pressure, higher rates of
expansion, accelerated speeds of engine, better construction in all
respects, as well as improved design, have enabled us to avail
ourselves to the utmost of the principles of Watt, and our mills, our
railways, our steamers and our fields, even, have gained almost as
extraordinarily by these advances, since the days of the great
inventor, as through his immediate labors.
With the introduction of the new form of older energy, electricity,
with the reduction of the lightning into thraldom, has now come a new
impulse affecting all the industries. Through its mysterious, its
still unknown action, steam now reaches out far from its own place,
driving the electric car along miles of rail; giving light throughout
all the country about it, turning night into day, and repressing crime
while encouraging legitimate labor, reaching into distant chambers and
every little workshop, to offer its powerful aid in all the
distributed work of cities. Without the steam engine there would be
little work available for electricity, but the appearance of this, the
latest and most useful handmaid of steam, has given the engine work to
do in an uncounted number of new fields, has called in the inventor
once more to adapt steam to its new work. The "high-speed engine" is
the latest form of the universal helper. And such has been the
readiness and the intelligence of the contemporary inventor that we
now have engines capable of turning their shafts three hundred
rotations a minute and without a perceptible variation of velocity,
whatever the change of load or the suddenness with which it is varied.
In the days of Watt a fluctuation of five per cent. in speed was
thought wonderfully small; in those of Corliss, the variation was
restricted to two per cent. and we wondered at this unanticipated
success. To-day, thanks to Porter and Allen, to Hartnell, to Hoadley,
to Sims, to Thomson, to Sweet, to Ide, and to Ball, we have seen the
speed fluctuation restricted to even less than one per cent. of its
normal average.
The inventors of the steam engine are, through their representatives
of to-day, according to the statisticians, doing the equivalent of
twelve times the work of a horse, for every man, woman and child on
the globe. We have not less, probably, than a half million of miles of
railway, transporting something over 150,000,000,000 of tons a mile a
year. A horse is reckoned to haul a ton weight about six and a half
miles, day by day, by the year together. In the United States, it is
reckoned that the steam engine, on the railways alone, hauls a
thousand tons one mile, for every inhabitant of the country, every
year, or, if it is preferred to so state it, a ton a thousand miles.
This is the way in which the East and the West are, by the inventors
of the steam engine, enabled to help each other. This costs about $10
each individual; it would require some 25 millions of horses to do the
work, and would cost about $1,000 a family, which is more than twice
the average family earnings.
Dr. Strong, in that remarkable book, "Our Country," says: "One man, by
the aid of steam, is able to do the work which required two hundred
and fifty men at the beginning of the century. The machinery of
Massachusetts alone represents the labor of more than 100,000,000 men,
as if one-half of all the workmen of the globe had engaged in her
service." And again: "Some thirty years ago, the power of machinery in
the mills of Great Britain was estimated to be equal to 600,000,000
men, or more than all the adults, male and female, of all mankind."
Mr. Gladstone estimated that the aggregation of wealth on the globe
during the whole period from the birth of Christ to that of Watt was
equaled by the production in twenty years, at the middle of this
century, with the aid of machinery driven by the fruit of the brain of
the inventors of the steam engine. We may probably now safely estimate
the former quantity as rivaled in less than five years, while, since
the birth of Watt and his engine, and the production of the spinning
mule, the power loom, the cotton gin and our own patent system and its
marvelous mechanism, all events of a century ago, we may estimate that
they have, together, accomplished more in this period which we now
celebrate than could have been done in a millenium of milleniums
without these now subjected genii. But the power behind all these
curious inventions and their work is that of steam. The steam engine
even supplies power to the telegraph and transports words and thought
as well as cotton bales and coal.
And now what has this combination of legislation for private
protection and public good, of a genius producing great inventions,
and of the accumulated capital of earlier years, brought about?
It has given us the best fruits of science in permanent possession.
The study of science invariably aids, in a thousand ways, the progress
of mankind. It gives us new conceptions of nature and of the
possibilities of art; it promotes right ways of work and of study; it
teaches the inventor and the discoverer how most surely and promptly
to gain their several ends, it gives the world the results of all
acquired knowledge in concrete form. This one instance which we are
now especially interested in contemplating has performed more
wonderful miracles than ever Aladdin's genii attempted. One man, with
a steam engine at his hand, turns the wheels of a great mill, drives
forty thousand spindles, applies a thousand horse power to daily work
in the spinning of threads, the weaving of cloth, the impulsion of a
steamboat, or the drawing of great masses of hot iron into finest
wire. This puny creature, his mind in his finger tips, exerts the
power of ten thousand men, working with muscle alone, and, aided by a
handful of women, boys and girls, clothes a city. A half dozen men in
the engine room of an ocean steamer, with a hundred strong laborers in
the boiler room and on deck, transports colonies and makes new
nations, brings separated peoples together, unites countries on
opposite sides of the globe, brings about easy exchanges between pole
and equator. One man on the footboard of the locomotive, one man
shoveling into the furnaces the black powder that incloses the energy
stored in early geological ages, a half dozen men mounted on the long
train of following vehicles, combine to bring to the mill girl in
Massachusetts, the miner in Pennsylvania, the sewing woman, and the
wealthy merchant, her neighbor in New York, the flour made in
Minnesota from the grain harvested a few weeks earlier in Dakota. All
the world is served faithfully and efficiently by this unimaginable
power, this product of the brain of the inventor, protected by the
law, stimulated and aided by the capital that it has itself almost
alone produced.
And thus have the inventors of the steam engine set in motion and
placed at the disposal of mankind for every form of useful work all
the great forces of nature; thus Hero of Alexandria touched the then
concealed spring which called all the genii of earth, fire, water and
air to do the bidding of the race. Thus Papin, Worcester, Newcomen,
Watt, and Corliss and others of our own contemporaries, have applied
the genii to their task of leveling mountains, traversing seas,
continents, and the depths of the earth, building ships, locomotives,
hamlets and cities, cottages and palaces, turning the spindle,
operating the loom, and setting motion and giving energy to every
machine, doing the work of thousands of millions of men, converting
barbarism into civilization, giving necessaries of life in profusion,
comforts in plenty, and luxuries in superabundance.
Aiding and working hand in hand with those other genii of progress,
the inventors of the printing press and of the telegraph, the
telephone, and the electric railway, of the modern system of textile
manufactures, of iron and steel making, of the mowing machine and the
harvester, they have compressed into two centuries the progress of a
millennium, destitute of their aid. Every step taken under their
stimulus, and with their help, is a step toward a higher life for all,
intellectually and morally as well as physically; every advance in the
improvement of their work is a gain to every man, woman, and child;
every improvement of the steam engine is a help to the whole world.
This progress makes the day of the extinction of the system now
grinding the populations of the earth into the ground, the day of the
abolition of armies and the restoration to the people of that freedom
which characterized the times of the patriarchs, and of the
restoration of the rights of the citizen to his own time and strength
and producing power, perceptibly nearer.
When this final revolution shall have been accomplished, and when all
the world has settled down to the steady and undisturbed work of
production by daily and regular labor, aided by the genii of steam, of
electricity, of all nature, combined for good, the results of the
intellectual activity of the inventors of the steam engine will be
fully seen. Then no monument will be required to keep green the memory
of Watt, Corliss, or any other of these great men, but it will be said
of them, as of Sir Christopher Wren in the epitaph in St. Paul's:
"Seek you a monument, look about you!" Every wreath of steam rising to
the heavens from factory, mill or workshop will be a reminder of Hero
of Alexandria, every mine will possess a memorial to Papin, Worcester
and Savery; every steamship will bring into grateful memory Fitch and
Stevens, and Bell and Fulton; thousands of locomotives, crossing the
continents, will perpetuate the thought of the Stephensons and their
colleagues in the introduction of the railway; the hum of millions of
spindles and the music of the electric wire will tell of the work of
Corliss and his contemporaries and successors who made these things
possible, and all kingdoms and races, all nations, will revere the
name of James Watt, the genius to whom the world is most indebted for
the beginnings of all this later and grander civilization which has
converted the slow progress of earlier centuries into the meteor-like
advance of to-day toward a future as grand and as mighty and as noble
as humanity shall choose to make it.
* * * * *
IMPROVED HAND CAR.
[Illustration]
In the accompanying illustration we show a new design of hand car,
being introduced by the Courtright Manufacturing Co., of Detroit. It
will be seen that the apparatus for propelling the car is very
different from the mechanism generally used. An upright framework
secured to the platform carries a large sprocket wheel, which is
connected to a smaller one upon one of the axles by means of a chain.
The larger sprocket wheel is rotated by means of a triangular shaped
lever attached at the lower corner to the crank of the sprocket wheel
and having a handle at each of its upper corners. It is hinged upon a
fulcrum which slides upon the two vertical rods shown in the
illustration. It will be seen that this gives a peculiar movement to
the handles by which the operators propel the car, but it has been
found that the motion is an excellent one, and it is claimed that a
higher speed can be obtained with the mechanism here shown than with
any other now in use. There is practically no dead center, as in the
case where the ordinary crank and lever is used. A number of leading
roads have given the car a trial, and being well satisfied it, have
given orders for more. The company claim that a car with 20 in. wheels
can easily be made to attain a speed of 15 miles an hour by two
men.--_Railway Review_.
* * * * *
THE CONIC SECTIONS.
By Prof. C.W. MACCORD, Sc.D.
In Fig. 1 let D be a given point, and O the center of a given circle,
whose diameter is FG. Bisect DF at A. Also about D describe an arc
with any radius DP greater than DA, and about O another arc with a
radius OP = DP + FO, intersecting the first arc at P, then draw PD,
and also PO, cutting the circumference of the given circle in L. Since
PD = PL, and DA = AF, it is evident that by repeating this process we
shall construct a curve PAR, which satisfies the condition that _every
point in it is equally distant from a given point and from the
circumference of a given circle_. Since PO-PD = LO, and AO-AD = FO,
this curve is one branch of the hyperbola of which D and O are the
foci.
[Illustration: FIG. 1]
Bisect DG at B, then about D describe an arc with any radius DQ
greater than DB, and about O another are with radius OQ = DQ-FO; draw
from Q the intersections of these arcs, the line QD, and also QO,
producing the latter to cut the circumference in E. By this process we
may construct the curve QBZ, each point of which is also equally
distant from the given point D, and from the concave instead of the
convex arc of the given circumference. The difference between QD and
QO being constant and equal to FO, and AB being also equal to FO, this
curve is the other branch of the same hyperbola, whose major axis is
equal to the radius of the given circle.
The tangent at P bisects the angle DPL, and is perpendicular to DL,
which it bisects at a point I on the circumference of the circle whose
diameter is AB, the major axis, the center being C, the middle point
of D O. As P recedes from A, it is evident that the angles P D L, P L
D, will increase, until D L assumes the position D T tangent to the
given circle, when they will become right angles. P will therefore be
infinitely remote, and the point I having then reached t, where D T
touches the smaller circle, C t S will be an asymptote to the curve.
This shows that the measurements from the convex arc, for the
construction of A P, are made only from the portion F T of the given
circumference.
In the diagram the point Q is so chosen that D L produced passes
through E, so that Q J, the tangent at Q, is parallel to P I. It will
thus be seen that the measurements from the concave arc, for the
construction of B Q, are confined to the portion G T of the given
circumference. As D L E rises, the points P and Q recede from A and B,
the points L and E approach each other, finally coinciding at T; at
this instant I and J fall together at t, so that S S is the common
asymptote to A P and B Q.
In Fig. 2 the given point D lies within the circumference of the given
circle. Bisect D F at A, and D G at B; about D describe an arc with
any radius D P greater than D A, and about O another, with radius O P
= O F--D P, these arcs intersect in P, and producing O P to cut the
circumference in L, we have P D = P L. Similarly E D = E H, U D = U W,
etc. And since P D + P O = L P + P O, D E + E O = H E + E O, and so
on, the curve is obviously the ellipse of which the foci are D and O,
and the major axis is A B = F O, the radius of the given circle.
[Illustration: FIG 2.]
If, as in Fig. 3, the given point be made to coincide with the center
of the circle, the ellipse becomes a circle with diameter A B = F O.
But if the point be placed upon the circumference, as in Fig. 4, the
ellipse will reduce to the right line A B coinciding with F O.
[Illustration: FIGS 3, 4, 5, 6.]
In this case we may also apply the same process as in Fig. 1; D T
becomes a tangent at D to the circumference, and the asymptotes
coincide with the axis of the hyperbola, of which one branch reduces
to the right line A P extending from A to infinity on the left, and
the other reduces to the right line B G Q, extending from B to
infinity on the right.
If the circle be reduced to a point, as in Fig. 5, the resulting locus
is a right line perpendicular to and bisecting D O. If on the other
hand the diameter of the given circle be infinite, the circumference,
as in Fig. 6, becomes a right line perpendicular to the axis at F, and
the curve satisfies the familiar definition of the parabola, D E being
equal to E H, D P equal to P L, and so on.
In Fig. 7, as in Fig. 1, DT is tangent at T to the given circle whose
center is O, and at t to the circle about C whose diameter is AB, the
major axis. Since DTO is a right angle, T lies upon the circumference
of the circle whose center is C, and diameter DO; this circle cuts the
asymptote SCS at M and N. The semi-conjugate axis is a mean
proportional between D A and AO; now drawing TM and TN, it is seen
that Tt is that mean proportional; and a circle described about C with
that radius will be tangent to TO. DT, then, is the radius of the
circle to be described about the focus of the conjugate hyperbola for
its construction according to the enunciation first given: and we
observe that DT and TO are supplementary chords in the circle about C
through D and O. The conjugate foci must therefore lie upon this
circumference, at D' and O'; and since D'O' is perpendicular to DO,
D'T will be perpendicular and T'O' will be parallel to SCS.
[Illustration: FIG 7.]
Now as TO increases, T'O' will diminish, until, when TO equals DO,
T'O' will vanish and with it Ct'; and at this crisis, the case is the
same as in Fig. 4; but the conjugate hyperbola logically reduces to
_two_ right lines, extending from C to infinity on the right and left.
As indeed it should from the familiar construction, since the
distances from D' and O' to any point on the horizontal axis being
equal, their difference is constant and equal to zero.
It appears, then, that a conic section may be defined as the locus of
a point which is equally distant from a given point and from the
circumference of a given circle. Boscovich defines it as the locus of
a point so moving that its distances from a given point and from a
given right line shall have a constant ratio.
The latter definition involves the conceptions of a rectilinear
directrix, and a varying ratio in the cases of the different curves,
this ratio being unity for the parabola, less for the ellipse, and
greater for the hyperbola. The former involves the conception of a
circular directrix with a ratio equal to unity in all cases; and the
two definitions become identical in the construction of the parabola,
which is in fact the only curve of which a clear idea is given by
either of them. That of Boscovich has been given a prominence far in
excess of its merits, being made the foundation for the discussion of
these important curves, and this in a textbook whose preface contains
the following true and emphatic statement, viz.:
"The abstract nature of a ratio, and the fact that it is a
compound concept, peculiarly unfit it for elementary
purposes."
The definition herein set forth has not been given in any treatise on
the subject, so far as we have been able to ascertain. And it is
presented with the distinctly expressed hope that it never will be,
except as a mere matter of abstract interest.
Of this it may, like the other, possess a little, but both have the
great disadvantage that, except in relation to the parabola, the idea
which they convey to the mind of the curves to which they relate, if
indeed they convey any at all, is most obscure and indirect; and of
practical utility neither one can claim a particle.
* * * * *
TABLE OF ATOMIC WEIGHTS.
(Issued December 6, 1890.)
By request of the Committee of Revision and Publication of the
Pharmacopoeia of the United States of America, Prof. F.W. Clarke,
chief chemist of the United States Geological Survey, has furnished a
table of atomic weights, revised upon the basis of the most recent
data and his latest computations. The committee has resolved that this
table be printed and furnished for publication to the professional
press. The committee also requests that all calculations and
analytical data which are to be given in reports or contributions
intended for its use or cognizance be based upon the values in the
table. It would be highly desirable that this table be adopted and
uniformly followed by chemists in general, at least for practical
purposes, until it is superseded by a revised edition. It would only
be necessary for any author of a paper, etc., to state that his
analytical figures are based upon "Prof. Clarke's table of atomic
weights of December 6, 1890," or some subsequent issue.
This table represents the latest and most trustworthy results, reduced
to a uniform basis of comparison, with oxygen=16 as starting point of
the system. No decimal places representing large uncertainties are
used. When values vary, with equal probability on both sides, so far
as our present knowledge goes, as in the case of cadmium (111.8 and
112.2), the mean value is given in the table.
The names of elements occurring in pharmaceutical, medicinal,
chemicals, are printed in italics[1]:
[Transcriber's Note 1: ITALICS represented by surrounding with "_".]
Name. Symbol. Atomic Weight.
_Aluminum_. _Al_ 27.
_Antimony_. _Sb_ 120.
_Arsenic_. _As_ 75.
_Barium_. _Ba_ 137.
_Bismuth_. _Bi_ 208.9
_Boron_. _B_ 11.
_Bromine_. _Br_ 79.95
Cadmium. Cd 112.
Caesium. Cs 132.9
_Calcium_. _Ca_ 40.
_Carbon_. _C_ 12.
_Cerium_. _Ce_ 140.2
_Chlorine_. _Cl_ 35.45
_Chromium_. _Cr_ 52.1
Cobalt. Co 59.
Columbium.[1] Cb 94.
_Copper_. _Cu_ 63.4
Didymium.[2] Di 142.3
Erbium. Er 166.3
Fluorine. F 19.
Gallium. Ga 69.
Germanium. Ge 72.3
Glucinum.[3] Gl 9.
_Gold_. _Au_ 197.3
_Hydrogen_. _H_ 1.007
Indium. In 113.7
_Iodine_. _I_ 126.85
Iridium. Ir 193.1
_Iron_. _Fe_ 56.
Lanthanum. La 138.2
_Lead_. _Pb_ 206.95
_Lithium_. _Li_ 7.02
_Magnesium_. _Mg_ 24.3
_Manganese_. _Mn_ 55.
_Mercury_. _Hg_ 200.
_Molybdenum_. _Mo_ 96.
Nickel. Ni 58.7
_Nitrogen_. _N_ 14.03
Osmium. Os 191.7
_Oxygen_.[4] _O_ 16.
Palladium. Pd 106.6
_Phosphorus_. _P_ 31.
Platinum. Pt 195.
_Potassium_. _K_ 39.11
Rhodium. Rh 103.5
Rubidium. Rb 85.5
Ruthenium. Ru 101.6
Samarium. Sm 150.
Scandium. Sc 44.
Selenium. Se 79.
_Silicon_. _Si_ 28.4
_Silver_. _Ag_ 107.92
_Sodium_. _Na_ 23.05
Strontium. Sr 87.6
_Sulphur_. _S_ 32.06
Tantalum. Ta 182.6
Tellurium. Te 125.
Terbium. Tb 159.5
Thallium. Tl 204.18
Thorium. Th 232.6
Tin. Sn 119.
Titanium. Ti 48.
Tungsten. W 184.
Uranium. U 239.6
Vanadium. V 51.4
Yterbium. Yb 173.
Yttrium. Yt 89.1
_Zinc_. _Zn_ 65.3
Zirconium. Zr 90.6
--_Am. Jour. Pharm._
[Footnote 1: Has priority over niobium.]
[Footnote 2: Now split into neo-and praseo-didymium.]
[Footnote 3: Has priority over beryllium.]
[Footnote 4: Standard, or basis of the system.]
* * * * *
THE TANNING MATERIALS OF EUROPE.
The tanning materials of Europe are of an altogether different type
from those of the United States. The population is so dense that the
quantity of home materials produced is not nearly proportionate to the
amount consumed, and consequently they must draw upon surrounding
lands for their supply. The vegetation of these adjacent countries is
of a much more tropical nature, and it naturally follows that the
tanning materials are also of a different species.
Tanning materials may be divided into two great classes, viz.:
Physiological and pathological.
PHYSIOLOGICAL.
The first class includes those tannins which are the results of
perfectly natural or normal growth, and a growth necessary to the
development of vegetation, for instance, bark, sumac, etc., whereas
the second class contains those which are the results of abnormal
growth, caused by diseases, stings of insects, etc. An example of this
is the gall. Both of these classes are used to a great extent in
Europe, while only the first division is in general use in the United
States. We will first consider the physiological tannins.
_Oak Bark._--This material was, is, and will be for some time to come
the main tanning material in use here in Europe. The advantages of the
oak tannage are as fully appreciated here as in the United States. The
European oak gives a light colored, firm leather, with good weight
results, is comparatively cheap and of an excellent quality. The
varieties are numerous, each country having its own kind. Those in
most general use are:
_Spiegel Rinde_ (mirror bark).--This bark is well distributed
throughout Europe, and is peeled when the tree has attained a growth
of from 12 to 24 years. It is marketed in three grades.
_Reitel Rinde_--Is obtained from the same tree as the spiegel rinde,
but after the tree has attained a growth of from 25 to 40 years.
_Alte Pische_ (old oak).--Obtained from the aged tree. It is not as
valuable as the younger bark, and consequently brings a much lower
price.
Spiegel rinde may be judged by small warts which appear on the shining
surface of the bark. The presence of a great number of these, as a
rule, indicates a high tannin percentage.
Bosnia has fine oak trees, the bark containing 10 to 11 per cent.
tannin.
Bohemia has the _trauben eiche_ (grape oak).
France uses the kirmess oak, which grows in the south of that country
and in northern Africa. Two grades are made, viz., root and trunk.
Tyrol has the evergreen oak--12 to 13 per cent. tannin.
Sardinia possesses a cork oak, which yields 13 to 14 per cent.
White oak is found throughout Europe, yielding 10 per cent. The price
of oak bark varies a great deal. The assortment is much more strict
than in the United States. In Austria it brings 4 to 5 fl., equal to
$1.60 to $2 per kilo. (224 lb.); in Germany, 11 to 16 marks per 100
kilos.[1]
[Footnote 1: In the principal districts in America, removed from the
cities, the price of oak bark is about $4 to $6 per cord or per ton
of 2,240 lb. The hemlock bark, which gives a sole leather just as
thoroughly tanned, but of a darker and reddish color, costs the
larger tanners from $3 to $4 a cord.]
The above mentioned varieties are all used for both upper and sole
leather. In Germany a great deal of upper leather is pure oak tannage,
but one seldom finds a pure oak tanned sole leather; it is almost
always in combination with other tannics.
_Pine Bark_--Is well distributed and is a very important tanning
material. It bears the same relation to oak bark here as does hemlock
in America, but its effects are quite different from hemlock. The best
Austrian sorts are those of Styria and Bohemia, but that of Karuthen
is also of good quality. The German pine comes from Thuringia to a
great extent. The countries that consume the greatest amount of pine
bark are Austria, Germany, Russia and Italy. The tannin contained
varies from 5 to 16 per cent. Its use is almost wholly confined to the
handlers, as its weight returns are not so satisfactory as oak or
valonia. In case it should be used for layers it is always in
combination with some better weight-giving tannic. For upper leather
its use is limited.
The bark is always peeled from the felled tree, and often the woodman
accepts the bark in part payment for his labor; he then sells the bark
to the tanner or agents who go about the country collecting bark. It
is generally very nicely cleaned. I would here like to correct a
mistake which tanners often make in their estimations of the value of
barks. A tanner usually buys the bark of southern-grown trees in
preference to that of trees grown in northern countries, as it is a
common idea that southern vegetation contains more tannin than that of
the north. This is a fallacy, as has not only been proved by careful
analyses, but may also be found to be an incorrect conclusion after a
moments' thought. Those trees which flourish in southern countries
grow very rapidly, and as tannin is necessary to the development of
leaf structure, etc., it is absorbed to a greater extent than is the
case with the slower-growing tree of the north. The tannin contained
in the sap does not increase in the same ratio as does the rapid
growth, and it follows that the remainder in the bark is less than in
the tree of slower growth.
_Birch Bark_--Is at home in Russia, Norway, and Sweden. It is used for
both upper and sole leather, but seldom alone. The bark is usually
peeled from the full grown tree, and contains 4 to 9 per cent. tannin.
_Willow Bark_--May also be found in the above mentioned countries and
also in Germany. This material is used for both upper and sole
leather, and contains 6 to 9 per cent. tannin. It is a very delicate
material to use, as its tannin decomposes rapidly.
_Erlen Rinde_--Is also a native of Germany, but is not used to any
great extent. The same may be said of the larch, although this variety
is also to be met with in Russia.
_Mimosa Bark_--Is obtained from the acacia of Australia. It is a
favorite in England. The varieties are as follows: Gold wattle, silver
wattle (blackwood, lightwood), black wattle, green wattle. The gold
wattle is a native of Victoria. Its cultivation was tried as an
experiment in Algeria and met with some success. The trees are always
grown from seeds. These seeds are laid in warm water for a few hours
before sowing. The acacia may be peeled at eight years' growth and
carries seeds. The Tasmania bark is very good; that from Adelaide
likewise good.
Sydney does not produce so good an article, but Queensland better. The
bark is marketed in the stick, ground or chopped.
Madagascar and the Reunion Islands have also a mimosa bark.
The mimosa barks give a reddish colored leather, pump well and contain
a high tannin percentage, 10 to 35 per cent.
Now we will consider the fruit tanning materials.
Valonia may truly be called one of the most generally used tanning
agents at present employed in Europe. All countries consume it more or
less. Valonia was first used in England about the beginning of this
century. A few years later Germany began using it, and still later
Austria introduced it. It is the fruit of the oak tree and is
obtainable in Asia Minor and the adjacent islands. In form it
resembles the American acorn, but in size it nearly trebles it. The
fruit may be divided into two parts, namely, the cup and acorn, and
the cup again divided into trillor and inner cup. The acorn only
contains 10 per cent. tannin, whereas the cup contains from 25 to 40
per cent.
The percentage depends altogether upon the time of harvesting and the
place of growth. The best valonia is derived from Smyrna, and is
naturally the highest priced article. Valonia is worth from 22 to 28
florins ($9 to $11) per 100 kilos. (224 pounds) at present. The other
provinces and islands from which it is obtainable are Demergick,
Govalia, Idem, Ivalzick, Troy (this is the best); Metelino Island, the
vicinity of Smyrna. The material sold in three grades--prime, mazzano;
seconds, una aqua; thirds, skart.
The product of Smyrna generally averages:
Tons. Price.
Prime. 2,000 to 3,000 28 florins.
Seconds. 5,000 to 10,000 25 "
Thirds. 20,000 to 30,000 22 "
The _Metilino_ valonia is a product of a neighboring island, and is a
very good article. It may be easily distinguished by its thin cup. It
is harvested in September.
The _Candia_ valonia is nearly as long as it is wide, in contrast to
the Smyrna, which is much wider than long. The recent harvest showed a
return of 800 to 1,000 tons, but no assortment is made. A grade called
the Erstlige is sold, this being the first which has fallen to the
ground before maturing.
A peculiarity of the valonia is that it often strikes out a sort of
sugar sweat, which gives the cup a less attractive appearance, but
denotes the presence of large quantities of tannin.
Valonia is used almost wholly for sole leather, either alone or in
combination with pine or oak bark or knoppern and myrabolams. The
union of valonia and knoppern is that in most general use. Valonia
gives the leather a yellowish appearance, as it deposits a great deal
of yellow bloom. The leather is very firm and of good wearing
qualities. The weight results are also excellent, as will be seen
below. To sole leather there are usually given from one to three
layers of valonia. The demand for valonia is increasing more and more
every year, and the present outlook does not indicate any relaxation
of its popularity. Its use for upper leather is very limited.
Myrabolams are mainly used in England and Austria, and give a nice
light-colored leather, both upper and sole, although rarely used
alone. Their main use is for dyeing purposes. They are indigenous to
the East Indies.
Sumac is so well known that treating of it is superfluous. Its use is
very extensive, and it is a general favorite for light, fine leather,
which is mostly used for colors.
_Gambier_--Is in general use in England and to some extent in Germany.
_Catechu_.--Obtained from India, resembles gambier greatly. Its use is
almost wholly confined to England. It is also consumed by the silk
manufacturers in preference to gambier, for weighting purposes.
PATHOLOGICAL.
We now leave the physiological class and take up those tanning
materials included in the pathological class, or those of abnormal
growth.
_Galls_.--These are not consumed to any great extent at the present
period, but formerly they were used quite extensively. The galls are
found upon the leaves of the oak or sumac, etc. The direct cause of
their growth is that a certain wasp (cynips galles) stings into the
leaf and after depositing its egg, flies away. The egg develops into a
larva and then into a full-fledged wasp, boring its way out of the
gall which has served as a protection and nourisher. This accounts for
the hole noticed in almost every gall. The different varieties include
Aleppo. It is found upon the same trees as the valonia and contains 60
to 75 per cent. tannin; Istrian galls, 32 per cent. tannin; Persian,
28 to 29 per cent. tannin. Chinese galls, giving 80 to 82 per cent.
tannin, are the results of the sting of a louse, and make a very
light-colored leather. The dyers also use this material for coloring.
_Knoppern_--Belongs to the family of galls, and is a most important
factor of commerce in Austria. The knopper is generally found on the
acorn or leaf of the oak tree. The greatest quantity is derived from
the steel oak of Hungary. The tannin contained varies from 27 to 33
per cent. Knoppern are not being used so much now as formerly, and
consequently the amount harvested lessens from year to year. Its main
use was and is in combination with valonia as layers for sole leather.
Valonia gives better weight results than knoppern, and is replacing
knoppern more and more every year. The combination of knoppern,
valonia and myrabolams is also quite popular, and gives good results.
Knoppern are seldom used alone, being generally combined with some
other tannin. Austria is almost the only consumer at present, but
Germany used it extensively formerly.
_Bark and Wood Extracts_--Are becoming general favorites throughout
Europe, partly because of their weight-giving qualities and partly as
the transportation costs so little; they can be used to strengthen
weak bark liquors.
_Oak Extracts_--Are well liked, both wood and bark, and are used
extensively. Slavonia furnishes a great deal of it.
_Chestnut Oak Wood Extract_--Is manufactured in quantities, and easily
finds purchasers.
_Pine Bark Extract_--Is also consumed in goodly amounts.
_Quebracho Wood Extract_.--The wood is shipped from Brazil to Hamburg
and other ports, and the tannin extracted there. Hamburg furnishes
quantities of it.
_Hemlock Extract_--Is used in Russia, and seems to have taken a hold
on the shoe buyers' fancies, as they now make imitations of it in
color. The hemlock that is consumed is imported from America.
As most leather is sold by weight in Europe, the leather manufacturers
aim to obtain as good weight results as possible, and often, I am
sorry to say, do so at the sacrifice of quality. This is common to
both upper and sole leather. Sole leather is nine times out of ten
given false weight by forcing entirely foreign substances into the
leather, such as glucose, barium chloride, magnesium chloride, resins,
etc. Glucose and resin are also used for weighting upper leather.
Leather is also weighted with extracts by overtanning. Leather buyers
have become very wary of late and do not purchase large quantities
before an analysis is made of a fair sample.
One more word before I close. The governments and private individuals
in Europe cultivate and raise trees for both lumber and bark purposes.
The forests are excellently cared for by efficient foresters, and the
result is that the tanners obtain much cleaner and better bark, and of
a very even quality. Would it not be a good idea if some individual,
who would certainly earn the everlasting gratefulness of the tanners,
would look into this matter, and see that not only the lumber side of
our forest cultivation is not neglected, but that the bark also is
preserved and cared for? Of course, we can obtain all the bark
necessary at present and for some time to come, but the time will come
when we shall certainly regret not having taken these steps, if the
lumbermen and bark peelers go on devastating magnificent forests.
Below will be found a table of weight results. Sole leather tanned
with these materials gives for every 100 lb. green hide the following
quantities of finished leather:
lb.
Oak bark 48 to 54
" extract 55 to 56
Pine bark 44 to 46
" extract 48 to 50
Willow 45 to 46
Birch bark and oak extract 49 to 51
Quebracho wood and extract 48 to 49
Valonia 52 to 56
Knoppern 51 to 53
Myrabolams 50
Knoppern, myrabolams and valonia 52 to 53
Hemlock 55
Specification of tanning materials used in different countries:
_France_.
Oak bark (kirmess).
Sumac.
Chestnut wood extract.
Quebracho " "
Some gambier.
_Italy_.
Oak bark.
Pine "
Sumac.
Valonia.
_England_.
Oak bark.
Divi divi.
Myrabolams.
Valonia.
Mimosa.
Extracts { Oak bark and wood hemlock.
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