The substance of this form is from _M'Kernan_; we cannot, however, avoid thinking, that his directions for this vat are very vague. _To dye silk a_ VIOLET, ROYAL PURPLE, &c. Boil archil with water in a copper; the quantity of archil according to the colour required must be from two to four times the weight of the silk. When the archil has boiled about ten minutes the fire must be damped, the archil left to subside, and the clear liquor put into a vessel of a convenient size, in which the silk is to be immersed and worked with care. You must have a small corresponding pattern that you intend for purple, which at times you must put into the blue vat to regulate the depth of the archil ground, as the purple is a compound colour, arising from the blue of the indigo and the red of the archil. When the red of the archil is deep enough, you must wash it off and put it into the blue vat with proper precaution. The fulness of the archil ground and the depth of the blue, must be regulated according to the patterns which are to be matched. _To dye silk_ LILAC. _Lilac_ is and should be a bright light shade of violet or purple; to give it the blue requires great management. The vats being generally too strong, it is best to mix a little of the new rich vat with some pearl-ash in clean cold water, and so prepare a liquor on purpose, by which the lilacs may be blued or reddened at pleasure. When this liquor is first mixed it becomes of a green colour; the silks therefore should not be dipped till the liquor begins to lose its green colour and inclines to blue. Pearl-ash added to this liquor helps to blue the archil, because the effect of the alkali upon red is to render it violet. _Another process for_ LILAC. Consists in simply using the _chemical blue_ with archil according to the shade required. _Another process for dyeing muslin, &c._ LILAC. This is accomplished by mixing the neutralized chemic blue for cotton with the pink dye of safflower, according to the shade required. _To dye silk a_ VIOLET _or_ PURPLE _with Logwood._ The silk should be alumed and washed. The logwood should be boiled in large quantities like fustic, as as directed for green; but it should not be kept longer than two or three weeks; it is far better used cold than hot. _To dye silk_ VIOLET _with Brazil wood and Logwood._ The silk must be alumed and cooled as usual; it is then to be alumed and dyed in a liquor made of Brazil wood of the common heat, then in the cold logwood liquor, and lastly, a solution of pearl-ash must be added to the liquor in which the silk is last dyed. It is afterwards to be washed and dried; but for some shades it is best to have fresh liquor, particularly for the warm Brazil, the cold logwood, and the solution of pearl-ash: in this case the quantity of each may be much better regulated. _To dye silk_ VIOLET _or_ PURPLE _with Brazil wood and Archil._