TOL. XLVII.] PHILOSOPHICAL TBANSACTIONS. ^33 



scription of it will not be necessary, as also the rest of these parts already men- 

 tioned being essential to every machine of this kind, a further account of them 

 may be dispensed with. What is peculiar to this engine, is a float within the 

 receiver, composed of a light ball of copper, which is not loose in it, but fas- 

 tened to the end of an arm, made to rise and fall by the float, while the other 

 end of the arm is fastened to an axis ; and consequently, as the float moves up 

 and down, the axis is turned round one way or the other. This axis is made co- 

 nical, and passes through a conical socket , which last is soldered to the side of 

 the receiver. On one of the ends of the axis, which projects beyond the socket, 

 is fitted a second arm, which is also moved backward and forward by the axis, as 

 the float rises or falls. By these means, the rising or falling of the surface of the 

 water within the receiver, communicates a correspondent motion to the outside, 

 in order to give proper motions to the rest of the geer, which regulates the open- 

 ing and shutting of the steam and injection-cocks ; and serves the same purpose 

 as the plug-frame, &c. in Newcomen's engine. The particular construction and 

 relation of those pieces will better appear by the figure and references, than can 

 be done by a general description. 



AB fig. 11, pi. 6, is an arm, which is fastened to a b, a conical axis, which 

 goes through a conical socket in c, a triangular piece soldered to the receiver. 

 This piece has this shape, to give liberty to the arm to rise and fall, that carries 

 the float on the inside, d e is a small cistern, soldered to the receiver ; which, 

 being kept full of water, keeps the axis and socket air-tight. This cistern is 

 constantly kept full of water, by means of a small leakage through the wooden 

 pegc, which follows the packthread cd to the cistern, e is a small weight to 

 counterpoise the float within, f is a slider ; which being set nearer to, or farther 

 from, the axis, will rise or fall a greater or less space, as may be required ; and 

 is fastened by the screw g. This slider is furnished with a turn-about, h i, which 

 is also fastened by a screw and nut at the end i, and sei-ves to adjust the length 

 of F G G H, a chain, which gives motion, by means of the shorter chain k 1, to 

 I K L, the balance, which opens and shuts the cocks ; and moves on the small 

 axis L. G G are two pulleys, supported by two arms, that are fastened to the 

 side of the receiver, and give the chain a proper direction in order to move the 

 balance, mn is the steam-cock; the end n being supposed to be detached from 

 a pipe, that gives it communication with the boiler, o is the injection-cock, 

 whose key is turned by the arm o m. p a is the injection-pipe, communicating 

 between the forcing-pipe above the valve, and the top of the receiver, r s is the 

 arm, by which the key of the steam-cock is worked, i k two rollers annexed to 

 the balance, which, by striking on the arm r s, open and shut the steam-cock, 

 as the balance is moved backward and forward, r n o is the steam-cock's key- 

 tail, which is furnished with two small rollers, n, o, which open and shut the 



