ARTIFICIAL LIGHT. 
83 
facfrure of composite candles. For this purpose the fatty acids 
of one kind of palm require to be mixed with stearine obtained 
from another kind of palm oil. 
The annoyance of having to snuff candles has been removed 
by plaiting and twisting* the wicks after dipping the cotton in a 
solution of borax. The way in which this contrivance acts is 
simple enough. It depends on the fact that flame is a mere 
shell. Owing to there being* no supply of oxygen gas within, a 
charring of the wick there takes place, as a natural consequence 
of exposure to the heat, but the carbon remains. When, 
however, the cotton has been previously twisted, the tension of 
the threads obliges the wick to curl outwards towards the shell 
of flame, where it becomes completely burned, while the earthy 
impurities of the cotton form a glass with the borax, and are 
thus got rid of without mixing with the fatty acids, which are 
apt to splutter if not protected in this manner.* 
Candles made of the stearine of any common fat, whether 
animal or vegetable, can now be prepared so as to imitate and 
almost rival wax and spermaceti. The latter substance may ulti- 
mately be superseded altogether by chemical contrivances; but it 
is not likely that wax will ever be excluded from our drawing- 
rooms. The bleaching of wax and its preparation for use in 
candles have scarcely been altered or simplified, except by some 
trifling change introduced in the structure of the wick. The 
material which will ultimately take the place of wax is paraffine, 
already largely used, but not yet cheap enough to command the 
market. 
Oil lamps have improved marvellously of late years. The 
ingenious contrivance bearing the name of its French inventor, 
M. Carcel, was a great step in the right direction. In this 
lamp the oil is raised by clock-work, so as continually to over- 
flow at the bottom of the burning* wick, which is thus never 
charred. The wick is circular, and a powerful draught of air is 
made to pass both within and without it by the use of a high 
glass chimney. Almost any kind of oil burns in it with great 
splendour, and for a long time without altering* the wick. In 
this, and a number of contrivances known by different names, 
the principle involved is that of producing as nearly perfect 
combustion as possible of the oil by carrying a column of air 
rapidly in the interior of a thin circular sheet of flame. In 
carrying out the principle thus enunciated, a great and impor- 
tant stride was made towards a good cheap light, and most of 
the modern alterations have been mere adaptations, applied with 
more or less ingenuity and taste. 
* See “ Faraday’s Chemical History of a Candle,” mentioned in our List 
of Books. 
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