i 
( '• ) 
Cylinders, where the Height is agreeable to the Scale* 
of the 7th Figure, but the Diameters of the middle 
and inner Cylinders are made Id's than they are in 
the Engine, to make the Space between ('where the 
Mercury rifes and falls) vifible ; and the Cylinders 
themfdves are reprefented by Tingle Lines. 
Ihe Quantity of Mercury us’d in this Engine is 
36 i Pounds, which being pour’d in between the outer 
and inner Cylinder, riles up to the Height of 16 Inches. 
When the Barrel is pull'd up (as in Fig* 9,^ fo as to 
have the middle Cylinder within an Inch of the Bot- 
tom of the Barrel ; the Mercury on both Tides the mid- 
dle Cylinder will rife up to the Height of 23,1 
Inches, that is about two Inches below the Cup Di, 
to the Line q q* 
When the Barrel is going down to fill the Tucking- 
Pipe and middle Cylinder C, the Mercury in the inner 
Shell will be 25 Inches high, and only 13 in the outer 
Shell, Fig. 9, where the Ibaded part reprefents the 
At the End of the lucking Stroke the Mercury is 
up to the top of the inner Cylinder, and Tcarce an^ 
Inch in the outer Shell. Fig* 8. 
In raiTing the PiBon from forcing to Sucking, the 
firll It Inch drives the Mercury out of the inner 
Shell, and raiTes it in the outer Shell 13,28 Inches. 
The Depth of an Inch of Water in the middle Cy- 
linder above the inner one or Plug is equal to a Space 
in the outer Shell of 13,18 Inches, and L of an Inch^ 
is equal to the Tame Height in the inner Shell. 
Therefore when the Mercury is equally high in 
both Shells, a Motion of t of an Inch of the Bar- 
rel will charge for Sudion- That is, upon letting 
down the Barrel only L of an Inch, the Pieflure 
of the AtmoTphere in the outer Shell will raife the 
Mercury in the inner one 13,28 Inches, at the Tame 
time 
