151 
gives a blue superior to the Mazarine, and the winter Grape., 
resembling very much the dyer’s Grape of the French, 
called noireau , gives the finest violet. 
SOLUTION OF TIN. 
To prepare this mordant, the French chemists take 
two parts of spirit of nitre and one of fuming spirit of 
salt. They dissolve in this liquor the purest tin that can 
he procured, they granulate it and throw it by degrees in 
the mixture. The quantity of tin must be to that of the li¬ 
quor as one to twenty, though more tin may be added if the 
liquor will dissolve it. To use this mordant it must be di¬ 
luted in two or three parts of clear stream water accord¬ 
ing to its strength, until it is found to have the acidity of 
vinegar or lemon juice. 
SCARLET. 
To make the best scarlet, three parts of water to one of 
solution of tin are mixed together, and to procure the 
different shades and varieties of light red, rose, and orange, 
the quantity of cochineal and mordant must be reduced. 
BLUE. 
To give a dark and unchangeable blue colour to wool, 
the French and German manufacturers mix one part of 
pulverised indigo of the best quality with eight parts of 
vitriolic acid, well concentrated, and leave it without being 
disturbed twenty-four hours. They then add by degrees 
to the mixture ninety-six parts of pure and soft water, and 
stir it repeatedly. The wool dipped into it comes dyed 
with a dark blue colour. If the colour, however, is too 
dark, and approaches too much to the black, it may be 
rendered lighter by soaking the wool or cloth a whole 
day in a bath composed of twenty-four parts of pure and 
soft water and one part of sea salt well dissolved and cold. 
Alum may also be used as a mordant for indigo, and if wool 
or cloth are immerged after it has been died with that mor¬ 
dant in a bath containing a solution of soda, it will acquire 
