THE EXHIBITION OF 1862. 
63 
case. One of the most curious points about this is the colour 
which it exhibits. The rich, deep, rose tint which the body 
communicates to’ silk, &c., instead of being concentrated and 
intensified until deepened almost to a black, here shines and 
glistens from the facets of the beautiful crystals until a rich 
metallic green lustre, sparkling in the sunshine like the plumage 
of tropical birds, or the wing cases of certain beetles. Crystals 
such as these are unattainable except when working on a manu- 
facturing scale. Laboratory experimentalists had already ascer- 
tained the fact that magenta was capable of assuming a regular 
form; but crystals such as compose this crown — the planes 
in some being nearly an inch across — can only be developed 
by manufacturers whose crystallizing vats hold upwards of 
£2,000 worth of colouring matter. 
Before leaving this subject, we may draw attention to the 
important branch of national industry which this manufacture 
is assuming, and pay our tribute of admiration to the skill and 
intelligence of the chemist who has succeeded in converting the 
most nauseous and repulsive by-products of gas manufacture 
into such lovely colouring agents. Through his exertions, 
England will cease to import colouring matters, and will 
become a dye-exporting* country. 
Another product of the distillation of coal now claims our 
attention. In 1841, Liebig said that it would certainly be one of 
the greatest discoveries of the age if any one should succeed in 
condensing coal-gas into a white, dry, odourless substance, 
portable, and capable of being placed upon a candlestick or 
burned in a lamp. Ten years afterwards, Mr. Young showed, 
in the Great Exhibition of 1851, a single candle made from 
paraffin, a waxy-looking solid, which was known to be obtained 
in small quantities from the distillation of peat, wood, or coal. 
Liebig’s prediction was here fulfilled. Paraffin is absolutely 
identical in composition with the most luminiferous portion of 
coal-gas, and only differs from it in being in a more condensed 
state ; its per-centage composition of carbon and hydrogen is, 
in fact, identical with that of olefiant gas. Another ten years, 
and the commercial manufacture of paraffin has assumed 
gigantic proportions, and Mr. Young’s establishment for its 
production, at Bathgate, ranks among the largest chemical 
works in the world. The composition of paraffin, indeed, 
renders it pre-eminently adapted for the production of light. 
It is a beautiful wax, melting at about 130°, and when heated 
to a considerably higher temperature (as when burning in the 
wick of a candle) it decomposes into true olefiant gas, producing 
a beautiful white light. A paraffin candle amounts, therefore, to 
a perfectly-constructed and portable gas works ; its flame is not 
like that of an ordinary candle, but is identical with that of the 
