C I0 3 ] 
Y is the pifton ; and 
Z the fixed valve. 
G V is a cylinder of wood, fixed upon the pump- 
rod, and reaches above the furface of the wa- 
ter ; this piece of wood being of fuch a thick- 
' nefs, that its fedtion is half the area of that of the 
pump-barrel, will caufe the furface of water to 
rife in the head, as much while the pifton is 
defcending, as while it is riling : and will there- 
by keep the gauge-rod F G more equally to its 
height. Note, the arch and handle M M is here 
reprefented on a different fide to what it is fhewn 
in the preceding figures, in order that its dimen- 
lions may the better appear. 
a a Ihews one of the two wires which ferve as di- 
rectors to the float, in order that the gauge rod 
F G may be kept perpendicular ; for the fame 
purpofe alfo ferves w, a piece of wood with a 
hole to receive the gauge-rod, and keep it up- 
right. 
b is the aperture of the fluice. 
c c a kant-board, for throwing the water more di- 
rectly down the opening c d, into the lower 
cittern : and 
c e is a Hoping board, for bringing back the water 
that is thrown up by the floats of the wheel. 
Fig. 3. reprefents one end of the main axis, with a 
feftion of the moveable cylinder, marked O in the 
preceding figures. 
A B C D is the end of the axis ; whereof the parts 
B and D are covered with ferrules or hoops of brafs. 
E is a cylinder of metal ; whereof the part marked 
F is 
