MECHANICS AND USEFUL ARTS. 19 



of effecting an immense saving in the present method of employing coal 

 as a generator of power. In our most economical expansive engines, 

 we recover nothing of that which we employ. The heat required to 

 convert the water into steam is delivered by the air-pump, diluted, so 

 to speak, with so much cold water ; and the problem is, to concentrate 

 that heat, and render it again available for generating steam. Whether 

 that problem can be ever solved while water is used as a medium, it is 

 impossible to predict. The gases appear to offer a better chance of 

 success ; and, accordingly, Mr. Ericsson employs the expansive force of 

 heated air in his engine, instead of steam. "The invention/' says 

 Mr. Ericsson's specification, " consists in producing motive power by the 

 application of caloric to atmospheric air, or other permanent gases, or 

 fluids susceptible of considerable expansion by the increase of tempera- 

 ture. The mode of applying the caloric being such, that, after having 

 caused the expansion or dilatation which produces the motive power, 

 the caloric is transferred to certain metallic substances, and again re- 

 transferred from these substances to the acting medium at certain inter- 

 vals, or at each successive stroke of the motive engine ; the principal 

 supply of caloric being thereby rendered independent of combustion or 

 consumption of fuel. Accordingly, whilst in the steam engine the 

 caloric is constantly wasted by being passed off into the condenser, or 

 by being carried off into the atmosphere, in the improved engine the 

 caloric is employed over and over again, enabling me to dispense with 

 the employment of combustibles, excepting for the purposes of restoring 

 the heat lost by the expansion of the acting medium, and that lost by 

 radiation ; also for the purpose of making good the small deficiency 

 unavoidable in the transfer of the caloric." 



The principal novelty of the invention appears to consist in the 

 employment of a condenser, which, when saturated with heat, is used 

 as a regenerator, or boiler, until it is sufficiently cool to act again as a 

 condenser. It is proposed to have two of these condensers, to be used 

 alternately. The arrangements consist of two cylinders, of unequal 

 dimensions, placed one over the other, the smallest uppermost, the pistons 

 of which are connected by a rod working through stuffing-boxes, one end 

 of which is attached to a crank, in the usual manner. The patentee 

 terms the upper the supply cylinder, the lower the working cylinder. The 

 lower one has a concave bottom, forming the roof of one of the furnaces ; 

 and the piston has a chamber bolted to it with corresponding concavity, 

 tilled with fire-clay and ashes, as a non-conducting material, to prevent, 

 as much as possible, the heat from reaching the upper part of the 

 cylinder. There is another cylindrical vessel, called the receiver, and 

 a* fourth, called the heater, which latter has also a concave bottom, 

 and a furnace beneath. Two vessels of cubical form are filled to their 

 utmost capacity, excepting small spaces at top and bottom, with discs 

 of wire net, or" straight wires closely packed, or other small metallic 

 substances or minerals, such as asbestos, so arranged as to have minute 

 channels running up and down ; these are called the regenerators. 

 These vessels are all connected by suitable arrangements of slide valves 

 and an exhaust chamber ; and the following is said to be the modus 

 operandi : Fuel having been placed in the fire-places under the work- 



