476 Steam Engines. 
91}^ A method of superceding the necessity of a fly wheelj by 
means of two circular crank and cog wheels attached by shackle- 
bars to the pistons of two cylinders. The crank wheels are cast 
in the same mould, and move a smaller cog wheel in the centre ; 
§0 that, when the piston in one cylinder has arrived at the bottom, 
the piston in the other, is just commencing its descent, and vice 
versa. The combined force of the pistons in each cylinder, being 
always the same. Here, no reservoir or accumulation of surplus 
force in a fly wheel, is necessary to carry the motion past the per- 
pendicular pressure j because, the instant one of the pistons with 
its attached crank wheel, has spent its force on the middle cog 
wheel, the other piston with its attached crank wheel, begins to 
act ; driving round the centre cog wheel in a similar and uniform 
direction. The two large wheels between which the smaller is 
placed, are connected together by a small beam or brace. This 
invention is contested by Mr. Ogden ; and with the dispute, I have 
nothing to do. It is worth while however, to compare it with Mr. 
Cartwright’s method of communicating rotatory motion ; see p» 
§4 of this volume. 
Mr. Dowers proposes making the valves of the common en- 
gine, answer the purpose of his regulating valves. If so, so much 
the better. There are practical difficulties attending the construc- 
tion of the boiler, and the augmenter ; but they are not insupera=» 
ble. 
If alcohol or ether, or any mixture of alcohol and water, can 
be used economically in steam engines, as good judges think may 
be done, this engine will afford the means of using it. But I know 
of no decisive experiments yet made on this important subject. 
Mr. Dowers, and I, in my laboratory, past whiskey diluted with 
from one half to two thirds Water, through a i^d-hot gun barrel, 
but the gas produced, was small in quantity and not inflammable. 
It was in fact no more than the air contained in the gun barrel.* 
The wasteful and unscientific practices of using steam little 
higher than to afford mere atmospheric pressure thus neglecting 
the force to be gained by a small addition of fuelf — — and of gene^ 
* The inside however had been previously oxyded. 
I It is surprising that Mr. Watt who first discovered and demonstrated 
(see p. 93, and 171 of this volume) that the elasticity of steam being in pro- 
portion to its density, its expansion when stopt off at l-4th, l-3rd or 1-2 the 
capacity of the cylinder will produce a power in a much greater ratio 
than l-4thj l-3rd or 1-2 of the whole, should have made so little use of this 
discovery in his steam engines. The time is approaching when steam of great 
