Dr. ingenhouszs Ac count,' tec. 
D the handle fixed to the pifton at bb, which is fquare to 
prevent the piftons turning round. 
e the hole in the fide of the air box. 
e the fcrew to flop the faid hole. 
F a piece of brafs with a female fcrew, which was fixed 
with three ftrong fcrews to the wooden handle. 
f a fcrew at the end of the air box which fcrewed into 
the piece F. 
g a piece of ivory fixed to the pifton. 
x the pifton, with the piece of conical ivory fixed to it. 
L the termination of the ivory cone which filled up the 
fmall end of the air box. 
M the perforation in the wooden handle, through which 
the brafs handle D pafles. 
N a brafs ball at the end of a wire, which pafles down 
the canal r in the ivory cone, 
o another piece of wire palling down the other canal, 
canals are filled with non -conducting fubftance. 
js an interftice between the two wires of about one line, 
through which, the electrical fpark, when given on 
the ball n v pafles and fets fire to the inflammable 
air in the air box. 
