Scientific American Supplement, No. 484, April 11, 1885 | Page 3

masses from each of them, but did not escape anywhere into the
house, showing that the pipes were sound. If the engineer wishes to
increase the severity of the test, he throws a wet cloth over the top of
the ventilating pipe, and so gets a slight pressure of smoke inside it.
* * * * *

THE GAS ENGINE.[1]
[Footnote 1: Lecture by Mr. Dugald Clerk, before the Literary and
Philosophical Society, Oldham.]
By DUGALD CLERK.
In earlier days of mechanics, before the work of the great Scottish
engineer, James Watt, the crude steam engines of the time were known
as "fire engines," not in the sense in which we now apply the term to
machines for the extinguishing of fires, but as indicating the source
from which the power was derived, motive power engines deriving
their vitality and strength from fire. The modern name--steam
engine--to some extent is a misleading one, distracting the mind from
the source of power to the medium which conveys the power. Similarly
the name "Gas Engine" masks the fact of the motors so called being
really fire or heat engines.
The gas engine is more emphatically a "fire engine" than ever the steam
engine has been. In it the fire is not tamed or diluted by indirect contact
with water, but it is used direct; the fire, instead of being kept to the

boiler room, is introduced direct into the motor cylinder of the engine.
This at first sight looks very absurd and impracticable; difficulties at
once become apparent of so overwhelming a nature that the problem
seems almost an impossible one; yet this is what has been successfully
accomplished in the gas engine. Engineers accustomed to the
construction of steam engines would not many years ago have
considered any one proposing such a thing as having taken leave of his
senses.
The late Sir William Siemens worked for many years on combustion
engines, some of his patents on this subject dating back to 1860. In the
course of a conversation I had with him on the subject of his earlier
patents, I asked him why he had entitled one of those patents "steam
engine improvements" when it was wholly concerned with a gas engine
using hydrogen and air in the motive cylinder, the combustion of the
hydrogen taking place in the motive cylinder. He answered me that in
1860 he did not care to entitle his patent gas or combustion engine
simply because engineers at that time would have thought him mad.
Notwithstanding this widespread incredulity among engineers, and the
apparent novelty of the gas engine idea, fire or combustion engines
have been proposed long, long ago. The first Newcomen steam engine
ever set to work was used by a Mr. Back, of Wolverhampton, in the
year 1711. Thirty-one years before this time, in Paris--year
1680--Huyghens presented a memoir to the Academy of Sciences
describing a method of utilizing the expansive force of gunpowder.
This engineer is notable as being the very first to propose the use of a
cylinder and piston, as well as the first combustion engine of a practical
kind.
The engine consists of a vertical open topped cylinder, in which works
a piston; the piston is connected by a chain passing over a pulley above
it to a heavy weight; the upstroke is accomplished by the descent of the
weight, which pulls the piston to the top of the cylinder; gunpowder
placed in a tray at the bottom of the cylinder is now ignited, and expels
the air with which the cylinder is filled through a shifting valve, and,
after the products of combustion have cooled, a partial vacuum takes
place and the atmospheric pressure forces down the piston to the
bottom of its stroke, during which work may be obtained.
On the board I have made a sketch of this engine. Some years previous

to Huyghens' proposal, the Abbe Hautefeuille (1678) proposed a
gunpowder engine without piston for pumping water. It is similar to
Savery's steam engine, but using the pressure of the explosion instead
of the pressure of steam. This engine, however, had no piston, and was
only applicable as a pump. The Savery principle still survives in the
action of the well-known pulsometer steam pump.
Denys Papin, the pupil and assistant of Huyghens, continued
experimenting upon the production of motive power, and in 1690
published a description of his attempts at Leipzig, entitled "A New
Method of Securing Cheaply Motive Power of Considerable
Magnitude."
He mentions the gunpowder engine, and states that "until now all
experiments have been unsuccessful; and after the combustion of the
exploded powder there always remains in the cylinder one-fifth of its
volume of air."
For the explosion of the gunpowder he substituted the generation and
condensation of steam, heating the bottom