376 Purifying of Coal-Gas.—Electrical Experiments. 
through which he passes the gas. We have, however, no idea 
that the one was copied from the other. 
Extract from Mr. G. Palmer’s Specification. 
“The gas may be made by any of the usual processes, and is 
to be conveyed in pipes toa condenser orrefrigeratory, to deprive 
it of its tar, ammoniacal liquor, and condensible ingredients. 
From thence it is to be conveyed to one of my purifiers, which 
consists of a vessel of any form, and made of cast iron or any 
other material which will stand the action of heat. This purifier 
is to be kept moderately red hot while in action ; to accomplish 
which, it may be set in the same furnace as the retorts, or heated 
by a separate fire (which will be governed by the nature and ex- 
tent.of the concern) so as to be visibly red by day-light. It must 
be understood that I mention this temperature as being sufficient, 
although a higher one will not be detrimental to the process, but 
will destroy the purifying vessel more rapidly. 
“This purifying vessel is to be nearly filled with the fragments 
or refuse clippings of sheet iron, timed iron plates, or any oxide 
of iron at a minimum of oxidation, such as common clay or ar- 
gillaceous iron ore, or finery cinders, or black oxide of iron ; and 
when so filled and heated the gas must pass through it, which 
will effect a partial decomposition of the sulphuretted hydrogen, 
to complete which it must pass into a box or cistern of cold 
water. The pipe which conveys the gas into the box or cistern 
should just dip into the water, and a pipe at the top of the cis- 
tern must communicate with the gasometer, into which the gas 
will flow perfectly pure, and can then be distributed and burnt 
as usual. The operation of this method of purification must be 
obvious to those who are acquainted with chemistry; for it will be 
readily observed, that the sulphuretted hydrogen contained in the 
gas will be decomposed, by the action of heat and the substances 
used, into hydrogen and sulphuric acid, whilst at the same time 
no sulphureous acid gas can escape the agents to which the crude 
gas is exposed.”” 
ELECTRICAL EXPERIMENTS. 
Bronzed tube. Take a glass tube of the height of the con- 
ductor and fix it on and in astand. Coat about three-fourths 
of the upper part of the inside of it with metal (the easiest me- , 
thod is by inserting pewter shavings), and fix a cap and ball on 
the top. Then varnish one half of the outside from the top to 
the bottom, and, when nearly dry, apply, with a pencil, a coat of 
bronze (not the sulphuretted oxide of tin). Place it near the 
conductor, and a beautiful ramified spark will pass the whole 
length of the tube. 
Bronzed plate. On a plate of glass twelve inches in diameter 
paste 
