! 
338 Mr. Cuthbertfon’s Apparatus, Fe. Aone 
nearly filled with water, by means of fcrews at a and J. 
O, a metallic wire, is made faft to the brafs cap A: the lower 
part of this wire is made of platina, and is brought as near as 
poflible to the piece ef, but not to touch it. When the in- 
firument is to be ufed, the ftop-cocks being kept fhut, the 
large veffel muft be detached from the receivers, by un+ 
{crewing the female ferews QQ, filled with oxygen gas by 
any of the common methods, and again put in its place. 
The receiver B, which has a hole in its fide at 0, muft then 
be filled with oxygen gas, and C with hydrogen; and, 
while electric fparks are made to pafs from the wire O to the 
aperture e, the cock 7 muft be opened, by degrees, till the gas 
takes fire. Stop the electric fparks and regulate the flame 
by turning the cock one way or the other. The cock m, 
which fupplies the oxygen gas, nruft be kept quite open, and 
the receivers be kept fupplicd, C to its lip and B to the hole 
o, by known meafures of the gafes, from time to time, while 
the procefs is continued. The’ paffage that leads from the 
hydrogen gas to the large veflel is made fmaller than that 
from the oxygen, that the gas may enter in a very {mall 
ftream. The hole in the fide of the receiver B is for the 
purpofe of preventing more oxygen gas being introduced 
than will fill it to that point, that the column of water may 
always be heavier upon the hydrogen gas, which has to 
force its way through a fmaller aperture than the | oxygen 
gas. The fame end would be.gaincd by making B only 
about half the depth of C. Both thefe receivers are open 
below, to receive the gas introduced under them. 
4 
NEW 
