ic 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. But the most wonderful thing about substantive coal-tar
colours is their immense tinctorial power, _i.e._ the very little
quantity of each required compared with the immense superficies of cloth
it will dye to a full shade.

TABLE A.[2]

-------------------------------------------------------------------------------
TWELVE GALLONS OF GAS-TAR
(AVERAGE OF MANCHESTER AND SALFORD TAR) YIELD:--
---------+---------+------+----------+----+--------------+---+---+--------+----
Benzene.| Toluene.| P |Solvent | H N| Naphthalene. | C | H | A | P
| | h |Naphtha | e a| | r | e | n | i
| | e |for | a p| | e | a | t | t
| | n |India | v h| | o | v | h | c
| | o |rubber, | y t| | s | y | r | h
| | l |containing| h| | o | | a | .
| | . |the three | a| | t | O | c |
| | |Xylenes. | .| | e | i | e |
| | | | | | . | l | n |
| | | | | | | . | e. |
---------+----------------+----------+----+--------------+---+---+-------------
1.10 lb.=|0.90 lb.=|1.5 |2.44 lb., |2.40|6.30 lb. = |17 |14 |0.46 lb.|69.6
1.10 lb. |0.77 lb. |lb. |yielding |lb. |5.25 lb. of |lb.|lb.|= 2.25 | lb.
of | of |= 1.2 |0.12 lb. | |alpha- | | | lb. of |
Aniline |Toluidine|lb. of|of Xylene | |Naphthylamine | | |Alizarin|
| |Aurin.|= 0.07 lb.| |= 7.11 lb. of | | | (20%). |