to the Boilers of ordinary Steam-Engines. 333 



merely for the purpose of safety; and at the end of it there 

 is an apparatus/, attached, by which the pressure is indica- 

 ted; g^ is the feeding or injecting pipe leading from the for- 

 cing pump h, which may be worked by a connexion to the 

 moving part of the engine. 



" In order to generate steam, the vessel a must be filled 

 with water, or other fluid or fluids, from the pump h, and 

 heated by a furnace, or otherwise : the steam, or escape- 

 valve h, being loaded by means of a weight, with a pressure 

 greater than the expansive force of the steam, to he genera- 

 ted from such water, or other fluid or fluids, at the time of 

 its generation. When the water, or other fluid or fluids, in 

 the generator, has attained the necessary degree of heat, say 

 from 400 to 500 degrees of Fahrenheit, more or less, an 

 additional quantity of water, or other fluid or fluids, is 

 pumped into the generator, sufficient to force out a portion 

 of that already heated in the generator from under the 

 weighted-valve 6, into the steam-pipe d, where it instantly 

 becomes steam. 



" An enlarged representation of the valve, and its seat, is 

 shewn in the section, Fig. 2. The valve is a spherical 

 bulb, falling into a concave seat, in the lower part of the 

 square chamber ; the upper part of the valve is a cylindrical 

 rod, upon the top of which the weight of the pressing-lever 

 is exerted ; the lower part of the valve is a triangular stem, 

 sliding up and down the cylindrical passage. When the ad- 

 ditional quantity of water is injected into the generator, by 

 means of the force pump as described, the bulb of the 

 valve rises from its seat, and a corresponding quantity of 

 heated water passes up between the cylindrical passage and 

 the sides of the triangular stem, into the square chamber, 

 where the pressure no longer operating upon that portion of 

 the water, it immediately becomes steam, and passes forward 

 through the steam pipe to the working cylinder. 



" In order that the operations may be renewed, and con- 

 tinued regularly, I make use of an adjusting weight on the 

 handle of the pump i, virhich is a small single-stroke forcing- 

 pump, with a weight performing the office of an air-vessel. 

 At the end of the pump-handle is a chain m, which I con- 

 nect with a simple crank movement, and thus, by a corres- 

 ponding adjustment between the weighted steam, or escape- 

 valve i, the throttle valve, (which it is not thought necessa- 



