[ 826 ] 
By the expanfion of the bar A, the fhorter aim 
of the lever B is prefled down : and as the fpace 
defcribed by each of the points of a lever is as 
the diflance from the fulcrum ; fo the longer arm 
of the lever B, which is 27 as long as the other ; 
is railed proportionably ; and the fecond bar C> 
2 feet 2 inches long, the lower end of which 
is placed to the point of the lever B, by a fm all pin, 
round which it is moveable j and the upper end, in 
like manner, to the Ihorter arm of the iecond lever 
D ; is raifed accordingly ; and thereby the longer 
arm of the lever D, which is as long as the other, 
is proportionably prefled down; to which is added 
the expanflon of the bar C, increafed, in like man- 
ner, by the lever D. , . . , 
The third bar E, 2 feet 4 inches long, is placed 
to the point of the longer arm of the lever D, and 
the fhorter arm of the third lever F, which it prefles 
down accordingly ; and the longer arm of this lever, 
which is four times as long as the other, is thereby 
proportionably raifed ; to which is alfo added the ex- 
paniion of the third bar E, increafed by the lever F. 
There is an arch-head d, fixed to the point of the 
longer arm of the lever F, to which the fourth bar 
G 2 feet long, is fixed by two chains, which rails 
and lower it, as that arm rifes or falls ; and, at the 
diflance of 2 feet 6 inches, there is a pulley H, 
3 inches diameter. There are two cords fixed to 
this pulley, furrounding it different ways, one lead- 
ing upwards, the other downwards, which pa s 
through the bar G, and are fixed to two fprings b K 
which keep them equally tight; and the bar clofe to 
