I.--It is easy to show that the existing common type of steam engine, even if perfect as a piece of mechanism, necessarily wastes a very large proportion of the heat-energy which is supplied to it, and that no possible improvement short of a complete change of type can greatly increase the efficiency of the best modern engine.
A steam engine, theoretically capable of fully utilizing the heatenergy supplied, and of delivering the mechanical equivalent of that heat, has never yetbeen constructed. The possibility of constructing such an engine has been denied by both physicists and engineers. :Nevertheless, theoretically perfect air and gas engines have been designed and built, and a steam engine can probably be made, which may fully utilize all heat not lost by conduction, radiation, and friction. The object of the present paper is to show, not only the possibility of designing such an engine, using steam as the working fluid, but also the probable practicability of constructing a machine which shall waste no heat, except by conduction and radiation, and no power except by friction, under conditions which the engineer will admit to be attainable.
The theory of the proposed new type of engine is perfectly simple; and its construction, although involving the overcoming of grave difficulties in the reduction of losses by triction to a satisfactory extent, may possibly prove no more difficult a problem, than have been many others already solved.
The working fluid is assumed to be steam, because the proposed type of engine cannot be adapted for use with the permanent gases without special and undesirable modifications.
II.--A very simple conception, originating with Sadi Carnot, wlao published it in his well known work on Heat, half a century ago, i has