I 
IS-l ORIGINAL COMMUNICATIONS. 
A. represents the fountain, which is a cylinder, or air-ves- 
sel, of copper, about 24 inches in length and 10 inches diame- 
ter, with convex heads, B B., the inner surface being thorough- 
ly coated with tin. 
D. A tube of lead or tin, about three-eighths of an inch in 
diameter, passing through the centre of one of the heads of 
the air-vessel, descending to the bottom, and open at the ends 
E E, into which a stop-cock F is inserted, and a discharging 
pipe attached with an orifice of an inch in diameter G. 
H. Another tube of similar dimensions passing through 
the margin of the same head, and in like manner open at the 
ends. 
