_Scarlet_.--The dye-bath is made with 1 lb. Saffranine Prima, 1 lb. Auramine, and 10 lb. Glauber's salt. The goods are entered into the dye-bath at about 120 deg. F., and well worked about, then the temperature is raised slowly. When the dye-bath is exhausted the goods are lifted, washed and dried. There are no pure basic scarlets, and the above and similar combinations of a basic red and a basic yellow are the (p. 104) only ways in which a scarlet can be dyed on wool with basic coal-tar colours. The basic colours are, in general, the hydrochlorides of some colour base, and in the process of dyeing the acid constituent of the wool fibre unites with the colour base, while the hydrochloric acid which is liberated passes into the dye-bath. The acid reds are a very large group of red dyes, of somewhat varied chemical composition, which all have the property of dyeing from baths containing Glauber's salt and sulphuric acid or acetic acid, the usual proportions being 10 per cent. of the former, and 2 to 5 per cent. of the acid. Some are best dyed from a bath containing bisulphate of soda. The dyeing should be started cold, or at a lukewarm heat, then steam should be turned on and the temperature raised to the boil, at which it is maintained for an hour; this boiling serving to more intimately fix the dye-stuff on the woollen fibre. The Eosine reds, of which Eosine in its various brands, Rose Bengale, Phloxine, Saffrosine and Erythrosine, are examples, are best dyed upon wool from a bath containing Glauber's salt and a little acetic acid. They do not require a very acid bath, hence the reason of using acetic acid. The method of dyeing is that given above as for basic reds, namely, enter into cold, or at most lukewarm bath, and raise the heat slowly, continuing the work until the shade required has been obtained. It is a good plan to start work in a neutral bath, and then when the material has become thoroughly impregnated with the dye-liquor to add the acetic acid. The shades obtained from these Eosine reds are remarkable for their brilliance, but unfortunately their fastness to light, washing, etc., is but slight, although it may be increased by treating the dyed wool in a bath of alum or acetate of lead. Some of the acid reds, _e.g._, Acid Magenta, Acid Violet, belong (p. 105) to the group of sulphonated basic dyes. The vast majority belong to the group of azo dyes, which can be employed to dye from palest pinks to the deepest crimson reds. Some dye very brilliant shades, others only yield dull reds. Some dye shades remarkable for their fastness to all agencies, soap, acids, alkalies, light and air; others dye shades which may be fast to soap, but loose to acids and light. Generally even shades are readily obtained on any kind of woollen fabric. It is practically impossible to name all the acid reds that are known and that may be used, but a fairly representative series of recipes will be given.