334 Methol of producing Heat, Light, and 
that heats it, so that it does not scale, but will last for years. 
The smoke, &c. is carried off into a chimney. The cover 
d-of the pot is made rather conical, to fit into the top of 
’ the pot close, and from the top of the cover the elbow-pipe 
proceeds as far as the mark a. The other end of the pipe 
with the elbow entering the water-joint is riveted to it 
after; when the lid or cover of the pot is put on, the bewels - 
or ears come over the elbow of the pipe that is on the Jid, 
and a wedge is put between them and this elbow, to keep 
down the cover air-tight, and a little clay or loam may be 
luted in the joint, if any gas should escape round the cover 
of the pot. The other elbow B goes into a water-joint, 
formed of a tube affixed to the cover of the purifier C5 
and another tube, which passes through the hd of the puri- 
fier: the elbow- pipe then goes over the inner tube, and 
when put on, the jointing is made good by pouring water 
into the space ‘between the tubes, which renders it air-tight. 
The gas, as the arrows show, passes down into the purifier 
C, which is rather more than half full of waters the use of 
this water-joint is for the convenience of removing the lid 
d, to which this pipe is attacheds* The purifier C is a 
weadért trough, with a sheet-iron top, to which the tubes 
are soldered, “andit is fastened to the trough to keep all 
secure and air-tight. The sheets of iron, ey fy gs hy a, Rs 
are alternately soldered to the iron top, and fastened to 
the wooden bottom. Now when the trough is_ half 
filled with water, the gas passes into it at ‘B; and as it 
can only find its way ont again at R, it must pass 
through the water, The inner pipe B reaches under the 
surface ‘of the water in the trough ; now when the gas is 
forced into the water, it would rise to the top of the puri- 
fier, and go along in a body to the end, and out at. the pipe 
R, if the sheets of iron, fy gh, t M. k, which stand 
across the trough with openings in them, alternately at top 
and bottom, did not stop it, force it to descend down into 
the water, and hinder-it from going any way but through 
these apertures, purifying it all the time it is passing 
through the whole body of water, until it is properly washed : 
it then escapes through the pipe R at the end of the trough 
C, then passes down “the pipe S, and is carried up into the 
reservoir or gazometer K. In the bottom of the purifier is 
an aperture, closed by a plug at D, to let off the ammo- 
niacal water and tar as it js deposited, and the pipe, with 
the cock E at the top of the purifier, is to burn away the 
spare gas when not to be used. 
Theres a stop-cock placed in the main pipe at F, that 
when 
