264 On the ammoniacal Liquor of Coal Gas. 
or cotter to the iron rod of the agitator, which passes through the 
copper tube c, which acts both as a water joint to prevent the 
escape of gas, and as a safety-tube (supposing any stoppage to 
take place between the washer and gasometer) ; d is an inverted 
copper dish, made fast to the iron rod and pierced (except in the 
centre for the diameter of about six inches) with holes an eighth 
of an inch in diameter, and at intervals of about an inch. 
This divides the gas into streams of small bubbles, thereby ex- 
posing a greater surface to the caustic lime, as well as keeping a 
quantity of gas under the dish, or shelf, equal to its diameter. 
e is astrap of iron likewise made fast to the perpendicular rod, 
which acts as an agitator when the handle 2 is turned round or 
forced up and down; fis a brass plug and socket of an inch and 
quarter internal diameter, to which is soldered the inch and 
quarter copper pipe g, which conveys the gas under the shelf d. 
The brass plugs which convey the gas in and out of the washer, 
as well as the pipe c, are fastened into the cask-head with resin 
cement. 
The condenser will, I trust, explain itself; it is also a cask 
having a head and bottom, and also an interposed disc a little 
above the latter, forming a tar chamber, to the bottom of which 
the tube of safety @ descends within half an inch. . The top of 
this cask or refrigerator i is open to introduce water, except a staff 
across the middle, just to steady the brass sockets and safety-tube. 
The communication pipes are of light inch-lead pipe, to which 
the plugs are soldered. I have never found them leak when well 
pushed down, and they are well adapted to facilitate the putting 
any part of the apparatus in or out of connexion in a moment. 
You will perhaps be inclined to smile, and say ‘* This smells 
of the brewery.” I am happy however to say, The brewery never 
smells of it; which is more than some gas concerns can boast. 
The peculiar construction of our retort, and the improved plan 
of setting it up, will shortly come before the public, through the 
medium of the Society for ‘the Encouragement of Arts, Manufac- 
tures and Commerce, should they think it worth their notice. 
I have readin a late number of the Journal of Science and the 
Arts, a short notice that Professor Stromeyer has obtained from 
coal a new acid, a new gum, and a gum resin, which have the 
properties of dyeing various colours. But as the method by 
which he obtains them is not even hinted at, perhaps the follow- 
ing experiments which I have been making, may not be unac- 
ceptable to some of your readers. 
On the ammoniacal Liquor of Coal Gas. 
Having long been surprised that this product of the gas ma- 
nufactory should find such difficulty of being disposed of to ad-. 
vantage, I began a set of experiments to ascertain its constitu- 
ents, 
