a New Steam-Engine without a Boiler. 23 



from the force pump to the generator, whence the water cir- 

 culates round and round the spirals from the circumference 

 to the centre of the under half of the generator, ascends the 

 centre pillar P, then circulates outwards from the centre of 

 the upper half of the generator to its circumference, and 

 escapes by the pipe S, that leads to the cylinder of the engine. 

 The pipe T is the one that conveys part of the escape steam 

 from the cylinder into the chimney. This generator works a 

 small high pressure engine, of which the following is a short 

 description : — 



The frame of it is of cast-iron, of the forjn of the upper part 

 of Mr Maudslay's portable engine with its parallel motion. 

 The piston of the cylinder is six inches in diameter, and the 

 length of the cylinder permits the piston rod to make a stroke 

 of seventeen inches. The steam is permitted to enter the cylin- 

 der alternately above and below the piston by means of a 

 spring slide valve wrought by the engine, and has a stroke of one 

 and two-eighths of an inch. The axis of the fly wheel cranks, 

 &c. is two inches and a quarter square ; the rounded parts two 

 and one-eighth inches in diameter. The fly is seven hundred 

 weight, and six feet in diameter. In the steam-pipe that leads 

 from the generator to the cylinder, there is a three-way cock 

 introduced, with a branch proceeding from it to the hot well 

 of the engine, by which the steam may be permitted either to 

 pass to the cylinder, or by one-third turn of the cock into the 

 hot well of the engine. This three-way cock answers for 

 stopping or starting the engine. As there is no space in this 

 kind of generator, as in common engine boilers, for the steam 

 to condense or expand, the common throttle valve is not ap- 

 plicable to this kind of generator ; but in place of it, a spring 

 slide valve is introduced in the steam-pipe between the three- 

 way cock and generator, with a branch from it communicating 

 with the branch pipe that leads between the three-way cock 

 and hot well. This slide valve is raised and lowered against a 

 very acute angled aperture by means of centrifugal balls, so 

 as to permit a necessary regulating quantity of steam to escape 

 into the hot well. In the pipe by which the steam escapes 

 from the cylinder into the chimney, there is a branch to the 

 hot well ; in this branch there is a cock by which the tempe- 



