ARTIFICIAL LIGHT. 
81 
Tlie sixty years that have passed since the beginning of this 
century have witnessed marvellous improvements in almost 
every article of domestic use., and so much has been added to 
the stock of common comforts, rendering many of the luxuries 
of former times quite indispensable, that the habits and tastes 
of all classes have become affected to an extent little thought 
of. In this matter of illumination a return to the former con- 
dition would involve so complete a subversion of our estab- 
lished customs as to be almost impossible ; and this will be 
evident when we briefly describe the existing sources of artificial 
light and the present condition of manufacture in respect to 
them. 
Candles are still used to an enormous extent : fifty thousand 
tons weight of tallow have been entered for home consumption 
in England each year during the last quarter of a century ; but 
candles, originally made of tallow alone, although still manufac- 
tured of unpurified tallow, are to a great extent becoming replaced 
by those composed of a substance derived from various animal and 
vegetable oils. But while the consumption of tallow has remained 
nearly stationary, the population itself, and the quantity of 
artificial fight of all kinds consumed by each family, have been 
increasing with great rapidity. Wax, like tallow, has continued 
to be imported, and is still used as before ; and another curious 
substance — spermaceti — long since made into candles, has never 
been a common material. Unimproved lamps for burning com- 
mon oils are also still in very extensive use ; but, in addition to all 
these, many new sources of artificial light have been discovered; 
one of which, more than all others, has helped to turn night 
into day. We allude, of course, to the common coal gas, which 
is not only obtained at once by simple distillation from coal, 
but the manufacture of which has led to so many and such 
extraordinary results of other kinds, that it might well be re- 
garded as one of the greatest and most useful discoveries of 
modern times. 
The contrivances now commonly adopted for obtaining artifi- 
cial light may be grouped under the following heads : — First, 
There are tallow candles, which are still largely employed. 
Secondly, Stearine, or composite, and, more recently, paraffine 
candles, which will ultimately, no doubt, replace tallow in domes- 
tic use. Thirdly, Wax and spermaceti candles, scarcely altered 
from their old construction, and which continue to be used for 
certain purposes, although the consumption is not increasing. 
Fourthly, Animal and vegetable oils used in lamps, either of 
the old kind or of improved construction. Fifthly, Certain 
mineral oils, such as naphtha, paraffine, and other similar sub- 
stances, used also in lamps, and replacing oil to some extent. 
Sixthly, Coal gas, obtained by the destructive distillation of all 
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