The least tincture of sulphate of iron in the water saddens the crimsons, takes off their yellow, and gives the violet cast; but if too much of the yellow is carried off, it may be restored by fustic. Nothing but sulphate of iron will sadden grain scarlets, logwood being quite useless for this purpose; sulphate of iron darkens greatly with galls. _Macquer_. _Another process for_ CRIMSON. When the silk is boiling in the soap-liquor, add one ounce of annatto, for every pound of silk, working it through the colander as directed, (page 136.) but without the composition or tartar: in some shades, however, both composition and tartar are admitted. The solution applied to cochineal with worsted has a considerable effect, changing it from a crimson, its natural colour, to a very bright fire colour; but it produces only a crimson when applied to silk; it gives, however, this colour a very beautiful tint; for, uniting with the tartar, it increases the effect without impoverishing the colour, and saving the annatto ground. _Macquer_. CRIMSON _by Brazil wood_. The silk should be first alumed, and then passed through a strong decoction of Brazil wood, half a pail to a pound of silk, which is to be worked, and put through an additional and strengthened dye of Brazil wood, and then washed off: if in _hard_ water this will generally crimson the Brazil wood sufficiently; but if in soft water a little pearl-ash must be added; about one pound of the clear solution of pearl-ash, or rather the clear solution of a pound of pearl-ash, as one pound of water will not, we believe, dissolve a pound of pearl-ash: this is enough for forty pounds of silk. _The decoction of Brazil wood_ is prepared thus: one hundred and fifty pounds of Brazil wood chips are put into a copper which holds about sixty buckets of water; the copper is then filled with water and boiled for three hours, the waste by evaporation being occasionally supplied. The fire is now damped, the clear liquor drawn off, the copper filled again, and again boiled for three hours more. This process is repeated four times in all, when the dye of the wood will be fully extracted. _Logwood_ and _old fustic_ are treated in the same manner, but only two boilings are required for these. In regard to crimson generally, see forward, _observations on dyeing silk crimson and scarlet_, and also some _observations_ on the _dyeing of wool scarlet_, page 85. _Of fine_ VIOLET.