( 9 ) 
Alterations, make the Engine reprefented by F/f. 
as it is fet up at my Houfe in Weflmhller, and by 
the Force ol one Man, raifes a Hogfhead of Water 
in little more than a Minute and a half to the Height 
of 17 Feet. Ail the Fault of the Machine of Fig,- ^ 
is, that the Pendulum Handle Ff is too long, and the 
Bottom of the middle Cylinder C ought to be juft 
in the middle of the Height to which the Water is 
CO be rais’d, fuppofing three Copper Cylinders to be 
as they are here : if like wife the Barrel D i Dr 
work’d under the forcing Pipe, the Lift would be 
eafier. Therefore I defcribe the Machine with the 
fmali Alteration rep'^efented in Fig. 6 . 
The fucking and forcing Pipe and Valves are mark’d 
with the fame Letters as in the other Figures ; and 
the Chains E i Ei mufl: be fuppos'd to hang from 
fuch Pullies, and to be mov'd by fuch a Pendulum as 
is in Fig. The Barrel D i Dr (call’d othervvife 
ihe outer Cylinder, and reprefented by the fame Let- 
ters in Fig. 7,) has within it another Cylinder (call’d 
the inner Cylinder or Plug, as Fig. j,) between 
which two Cylinders a certain Quantity of Mercury 
is pour’d in, and the hanging Cylinder C coming 
down into the Mercury, a Stroke of 13 Inches may 
be made by the Motion of the Barrel, which, in ga- 
I ing down fucks by making a Vacuum in C, and in 
going up forces the Water out of the top of the 
forcing Pipe, performing the Office of a common Pi- 
flon ; only that inftead of Leather to make it tight 
to the Cylinder C, there is always a chin Shell of 
ij Quickfilver cither between the middle Cylinder C and 
1 the inner one, (dddd Fig. y.) as happens when the 
Sudtion is made, or between the middle and outer 
Cylinder, as happens in lifting up the Barrel to 
Force; In the Sudion, the Mercury is higher in the 
