DOMESTIC MOTORS. 333 



tained fitted with a governor and the necessary pulleys at a slight 

 increase of cost. The pumping-engines have found their way into 

 very general use on railroads, country seats, and in city buildings, 

 and from their economy in the use of fuel and their little trouble they 

 have in all these situations proved very satisfactory. They are made 

 only with coal-burning furnaces, and are on this account more trouble- 

 some than they would be if using gas, but are still but little more so 

 than an ordinary coal-stove. Replenishing of fires and oiling are the 

 only duties to be performed, and these can be done by unskilled labor. 

 The engine occupies about the same floor-space as a moderately large 

 coal-stove, and is about the same height. Two sizes are made, one of 

 six, and one of ten-inch cylinder. The former will pump five thou- 

 sand gallons of water to a height of ten feet in an hour, or a smaller 

 amount to a proportionally greater height, at an expenditure of four 

 pounds of coal, and the latter will raise twelve thousand gallons to 

 the same height, in the same time, with eight pounds of coal. These 

 amounts of coal are those used when the engine is run consecutively 

 for ten hours. If run for a shorter time, the coal consumed per hour 

 will be somewhat greater, owing to the starting of the fire. The en- 

 gines weigh considerable, the smaller size being some sixteen hundred 

 pounds, and the larger about double. The prices do not differ mate- 

 rially from those of steam-engines of from one to three horse-power. 



The internal construction of the engine and manner of working; 

 are shown in the sectional view in Fig. 10. It is also of the type 

 which repeatedly uses a given body of air, but, unlike the motor of 

 Ericsson, the alternate heating and cooling are done in separate cylin- 

 ders. The air is heated in the cylinder B and cooled in the cylinder A. 

 The plunger C fits the cylinder A in its upper portion, but is con- 

 tracted in the lower part to allow of an annular space between it and 

 the wall of the cylinder. The power-piston D also fits its cylinder 

 B tightly in the upper portion, but loosely in the lower heated part. 

 A leather packing, K K, in each cylinder secures as in other engines 

 a perfect fit of these moving parts. Between the two cylinders is 

 placed a regenerator, H, consisting of a number of perforated plates, 

 through which the air passes in going from one cylinder to the other. 

 Around the lower portion of the cylinder B is a water-jacket, E, and 

 encircling the same part of the heating cylinder B is a metal shell, 

 F, curved inward at the base. The extension G of the cylinder B 

 down into this shell forms a narrow annular space, through which the 

 air entering the heater has to pass in a thin sheet, and thus becomes 

 thoroughly heated. In action, the plunger C descends and compresses 

 the air below it to one third its previous bulk ; then by the further 

 upward movement of the power-piston D and the completion of the 

 down-stroke of the plunger, this air is transferred to the heater. This 

 compressed air becoming heated expands and forces the power-piston 

 to the end of its stroke, and entering the cylinder A carries the plunger 



