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PREPARATION OF BROWN AND VIOLET 
COLOURS. 
AKE one part by weight of rosaniline and mix it with 
one part also in weight of formic acid and half a part 
of acetate of soda, heat the whole at a temperature of 180° 
to 200° C. The mixture commences to dissolve at the mo- 
ment it attains the temperature of 140°, and in a short time 
as the measure of the temperature rises, it becomes a dark 
brown. If, however, it is dissolved in spirits of wood or 
alcohol, it produces a red scarlet colour. 
If instead in the operation when the mixture becomes 
brown, the heat is applied until it attains the temperature 
of about 260°, and it is dissolved in spirits of wood or alco- 
hol, a colour of orange red appears. 
In following up the operation until the mixture arrives 
nearly to the temperature of 275°, and is dissolved in alco- 
hol, the colour becomes orange yellow. After having pro- 
duced one of the other colours, if it is allowed to cool, the 
matter becomes hard, and may then be employed as a dye 
for impressions. 
For preparing the finest colouring matter,—brown—mix 
the matter or production after it has become scarlet red, 
with oil of aniline in the proportion of three parts of oil for 
one part of red-scarlet matter, and heat the whole at the 
temperature indicated, and separate the excess of oil of 
aniline by the known process. 
To obtain a violetcolour, mix the rosaline with valewane 
acid in the proportion of one part by weight of the first, 
and one part also by weight of acid, and heat it until the 
mixture commences to thicken and attains the temperature 
which varies accordingly to what is required, the mixture 
becoming more blue according to the heat applied, until it 
arrives at a violet blue. 
It is left to cool and then boiled in water, and again 
allowing it to get cool the colour is ready for use. 
With this colouring matter you may dye print on silk or 
on linen a fine violet-red or violet-blue. 
To prepare this colouring matter, violet, valerianic acid 
may be substituted to those of the same group, such as 
those of steuric, butyric, acetic, and cénanthylic, &c., but 
the preference should be given to valerianic acid. 
