Scientific American Supplement, No. 484, April 11, 1885 | Page 5

year, 1860, the famous "Lenoir" engine appeared. The use of
high pressure steam engines had long been common, and Lenoir's
engine was analogous to the high pressure engine, as Buren's was to the
condensing engine. It created a very general interest, and many engines
were constructed and used in France, England, and America; it
resembled very much in external appearance an ordinary high pressure
horizontal steam engine, and it was double acting.
During the following six years, other 20 British patents were granted,
and the gas engine passed from the state of a troublesome toy to a
practicable and widely useful machine.
From 1791 to the end of 1866, in all 46 British patents were granted for
gas engines, and in these patents are to be found the principles upon
which the gas engines of to-day are constructed, many years elapsing
before experience enough was gained to turn the proposals of the older
inventors to practical account.
The most important of these patents are:
No. Year. Robert Street 1,983 1794 Direct-acting engine. Samuel
Buren 4,874 1823 Vacuum engine. Samuel Buren 5,350 1826 Vacuum
engine. W.L. Wright 6,525 1833 Direct-acting engine. Wm. Barnett
7,615 1838 Compression first proposed. Barsante & Matteucci 1,072

1854 Rack & clutch engine. Drake 562 1855 Direct-acting engine.
Lenoir 335 1860 D.I. engine, electric ignition. C.W. Siemens 2,074
1860 Compression, constant pressure. Hugon 2,902 1860 Platinum
ignition. Millein 1,840 1861 Compression, both constant vol. and
pressure. F.H. Wenham 1,873 1864 Free piston. Hugon 986 1865
Flame ignition. Otto and Langen 434 1866 Rack and clutch, flame
ignition.
Leaving for the present the history of the gas engine, which brings us to
a stage comparable to the state of the steam engine during the
Newcomen's time, it will be advisable to give some consideration to the
principles concerned in the economical and efficient working of gas
engines, in order to understand the more recent developments.
It has been seen that gunpowder was the explosive used to produce a
vacuum in Huyghens' engine, and that it was abandoned in favor of gas
by Buren in 1823. The reason of departure is very obvious: a
gunpowder explosion and a gaseous explosion differ in very important
practical points.
Gunpowder being a solid substance is capable of being packed into a
very small space; the gas evolved by its decomposition is so great in
volume that, even in the absence of any evolution of heat, a very high
pressure would result. One cubic inch of gunpowder confined in a
space of one cubic inch would cause a pressure by the gas it contains
alone of 15,000 lb. per square inch; if the heating effect be allowed for,
pressures of four times that amount, or 60,000 lb. per square inch, are
easily accounted for. These pressures are far too high for use in any
engine, and the bare possibility of getting such pressure by accident put
gunpowder quite outside the purpose of the engineer, quite apart from
any question of comparative cost. In a proper mixture of inflammable
gas and air is found an exceedingly safe explosive, perfectly
manageable and quite incapable of producing pressures in any sense
dangerous to a properly constructed engine.
The pressure produced by the explosion of any mixture of gas and air is
strictly determined and limited, whereas the pressure produced by the
explosion of gunpowder depends greatly upon the relation between the
volume of the gunpowder and the space in which it is confined.
Engines of the "Lenoir" type are the simplest in idea and construction;
in them a mixture of gas and air is made in the cylinder during the first

half of the piston stroke, air being taken from the atmosphere and
drawn into the cylinder by the forward movement of the piston. At the
same time gas entering by a number of holes, and streaming into the air
to form an explosive mixture, the movement of a valve cuts off the
supply, and brings the igniting arrangement into action. The pressure
produced by the explosion acting upon the piston makes it complete its
stroke, when the exhaust valve opens exactly as in the steam engine.
The Lenoir and Hugon engines, the earlier forms of this type, were
double acting, receiving two impulses for every revolution of the crank,
the impulse differing from that in a high pressure steam engine in
commencing at half stroke.
The Lenoir igniting arrangement was complicated and troublesome. I
have it upon the table; the mixture was ignited at the proper time by the
electric spark produced from a primary battery and Ruhmkorff coil.
The Hugon engine was an advance in this respect, using a flame ignited,
and securing greater certainty of action in a comparatively simple
manner.
It is really a modification of Barnett's lighting cock described in his
patent of