(Stannous chloride, tin crystals, tin salts, muriate of tin.)

Tin is not so useful as a mordant in itself, but as a modifying agent

with other mordants. It must always be used with great care, as it

tends to harden the wool, making it harsh and brittle. Its general

effect is to give brighter, clearer and faster colours than the other

mordants. When used as a mordant before dyeing, the wool is entered

into the cold mordant bath, containing 4 per cent of stannous

chloride and 2 per cent oxalic acid; the temperature is gradually

raised to boiling, and kept at this temperature for 1 hour. It is

sometimes added to the dye bath towards the end of dyeing, to

intensify and brighten the colour. It is also used with cochineal for

scarlet on wool in the one bath method.