From carbolic acid are
obtained both Aurin and picric acid, and here is the actual quantity of
Aurin obtainable (1-1/4 lb.). From naphthalene, either naphthylamine (a
body like aniline) or naphthol (resembling phenol) may be prepared. The
amounts obtainable you see in the table. There are two varieties of
naphthol, called alpha- and beta-naphthol, but only one phenol, namely,
carbolic acid. Naphthol Yellow is of course a naphthol colour, whilst
Vermilline Scarlet is a dye containing both naphthylamine and naphthol.
You see the quantities of these dyes, namely 7 lb. of Scarlet and 9-1/2
lb. of the Naphthol Yellow. The amount of pure anthracene obtained is
1/2 lb. This pure anthracene exhibits the phenomenon of fluorescence,
that is, it not only looks white, but when the light falls on it, it
seems to reflect a delicate violet or blue light. Our table shows us
that from the 12 gallons of tar from 1 ton of coal we may gain 2-1/4 lb.
of 20 per cent. Alizarin paste. Chemically pure Alizarin crystallises in
bright-red needles; it is the colouring principle of madder, and also of
Alizarin paste.
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