[ 4 2 6 3 
CD the rod of the piilon, which palfes through 
MN the plate, which doles the top of the barrel. 
K is the collar of leathers, through which the pifton- 
rod palfes. When the pifton is at the bottom of 
the cylinder, the upper part of K is covered by 
the cap at D , to keep out dull, &c. 
L is the valve on the upper plate, which is covered 
by the piece 
OP, which is connected with the pipe 
O/?, which makes the communication between the 
valve and cock. 
CE is the pifton ; and 
EFF is the pifton- valve. 
II are two little holes to let the air pafs from the 
pillon- valve into the upper part of the barrel. 
GGK is the principal valve at the bottom of the 
cylinder. 
HH is a piece of metal, into which the valve GGK 
is ferevv’d, and doles the bottom of the cylinder j. 
out of which alfo is compofed 
SS the cock, and 
KTT the dud from the cock to the bottom of the 
barrel . 
HI'/ is the key of the cock. 
X the ftem $ and 
/ '/ the handle. 
Fig. III. 
Is an horizontal fedion of the cock, through the 
middle of the dud FT. 
/IB reprefents the bignefs of the circular plate, that 
doles the bottom of the barrel. 
CD 
