[ 437 ] 
give proper motions to the reft of the geer, which 
regulates the opening and (hutting of the fteam 
and injedlion-cocks ; and ferves the fame purpofe as 
the plug frame, &c. in Newcomen’s engine. The 
particular conflrudtion, and relation of thofe pieces, 
will better appear by the figure and references, than 
can be done by a general defcription. 
A B an arm, which is faftened to 
a b, a conical axis, which goes through a conical 
focket in 
C, a triangular piece folder’d to the receiver. This 
piece has this fhape, to give liberty to the arm to 
rife and fall, that carries the float on the infide. 
Z) E is a fmall ciftern, folder’d to the receiver ; which, 
being kept full of water, keeps the axis and focket 
air-tight. This ciftern is conftantly kept full of 
water, by means of a fmall leakage through the 
wooden peg c , which follows the packthread c d 
to the ciftern. 
<?, is a fmall weight to counterpoife the float within. 
f y is a Aider ; which being fet nearer to, or farther 
from, the axis, will rife, or fall, a greater or 
lefler fpace, as may be required; and is faftened 
by the fcrew g. This Aider is furnifti’d with a 
turn-about, h i> which is alfo faftened by a fcrew 
and nut at the end /, and ferves to adjuft the 
length of 
FGGH, a chain, which gives motion, by means of 
the fhorter chain k /, to 
lKL y the balance, which opens and ftiuts the cocks ; 
and moves upon the fmall axis L. 
GG are two pullies, fupported by two arms, that are 
faften’d to the fide of the receiver, and give the 
chain, 
