166 ARTIFICIAL ILLUMINATION. 
Acetyline is evolved by the action of water upon calcic carbide, and 
caleic carbide is produced by fusing together lime and coal dust in an 
electric furnace. The resulting carbide is a heavy dark grey substance, 
a pound of which will yield a little more than five cubic feet of 
acetyline, which gas can be evolved from the carbide by simply 
allowing water to drop upon it, in which way, in fact, the gas in this 
holder has been generated from the carbide in a small flask. We have 
had to be exceedingly careful to prevent leakages, as the slightest 
trace of acetyline in the air is peculiarly objectionable on account 
of its pungent and disagreeable odour. 
One difficulty connected with the practical use of acetyline is its 
liability to combine with copper and some other metals with which it 
might come into contact, but really the question as to whether it will 
ever be largely used is that of the cost of the manufacture of the carbide. 
Where power is cheap, as at Niagara, for instance, we are told that it 
may be produced at about £3 per ton, but there is little hope, I think, 
that it will be obtainable in Hngland at less than perhaps £6 or even 
£10 per ton, at which price acetyline will hardly be able to complete 
with existing methods of illumination, except perhaps under special 
circumstances where coal gas cannot be obtained, and for portable 
lights, to which latter it may be well adapted, inasmuch as the gas can 
be easily compressed into the ordinary iron cylinders, or indeed may 
be condensed into a liquid if a pressure of 21} atmospheres be applied. 
Under any circumstances considerable care will have to be taken in the 
management of it if pure acetyline gas is to be used as an illuminant. 
Within the limits of a single lecture, of course, it is impossible to 
include a proper discussion of the merits of petroleum and electricity 
as lighting agents as well as those of gas, to which I have chiefly 
devoted my attention. I propose later on to show you comparative 
estimates of the economies of these three illuminants, and I fear time 
will not permit me to do much more ; but I will just call your attention 
to the latest departure in petroleum lighting, viz.:—a very clever and 
apparently successful design of a petroleum lamp on the regenerative 
principle. The lamp now hanging before you, and which has been 
burning brilliantly until I had to extinguish it, as you remember, 
before the use of the lantern, has been submitted to me by the 
“Gloria Wickless Lamp Company.” Up to the present in my hands 
it has certainly given a very high efficiency. I do not propose to quote 
figures in connection with it until I shall have given the lamp a three 
months’ practical test. I may say, however, that it appears to me to 
be a very great advance on anything yet produced in this direction, 
and to be capable of providing a brilliant white light of from 100 to 180 
candle power at a very trifling cost for oil. It has the drawback, 
however, that it requires a few minutes’ careful attention when 
lighting it. The principle is a simple one: the oil falling drop by drop 
from a receiver at the top of the lamp into a chamber which is heated 
by the flame burning underneath it, is turned into gas, which, issuing 
from a number of small burners arranged in a circle below, gives an 
exceedingly bright light. The lamp is really, therefore, a gas lamp 
which automatically generates its own gas supply from liquid petroleum, 
and the regenerative effect which gives the intense whiteness to the 
