The Dyer's Guide. Chapter IV. On Scouring and Dyeing Wool. To dye wool with lac-dye, scarlet, or crimson

The Dyer's Guide
Being a Compendium of the Art of Dyeing
Linen, Cotton, Silk, Wool, Muslin, Dresses, Furniture, &c. &c.
With The Method of
Scouring Wool, Bleaching Cotton, &c.
And
Directions for Ungumming Silk, And For Whitening And Sulphuring Silk And Wool.
And Also
An Inttroductory Epitome of The Leading Facts in Chemistry, As Connected With The Art of Dyeing.

By Thomas Packer,
Dyer and Practical Chemist.

"Cet arte est un des plus utiles et des plus merveilleux qu'on connoisse."
- Chaptal.

"There is no art which depends so much on chemistry as dyeing."
- Garnett.

Second Edition,
Corrected and Materially Improved.

London:
Printed for Sherwood, Gilbert, And Piper,
Paternoster-Row.
1830.
We have mentioned lac-lake and lac-dye in page 12. Lac-lake is of very uncertain quality, having many heterogeneous substances mixed with it. Lac-dye is very superior to lac-lake. Lac-dye is much used for dyeing woollen yarn scarlet -and crimson, for carpets and hearth-rugs. It is used with a peculiar spirit, which may be purchased of the dry-salters. Some think that this colouring material is nearly equal to cochineal; the author has, however, never seen any thing dyed with it equal to the colour obtained from cochineal, although it affords, nevertheless, a good scarlet.

Lac-dye is used by being powdered and put into a stone pan, (the quantity must be in proportion to what is likely to be used), with a portion of the above-named lac-spirit sufficient to make it about as fluid as treacle; it must be stirred with a glass-rod or a tobacco-pipe. Some use alum and tartar as a preparation, and some not. After putting the mixture of lac -lake and spirit in the copper with a proper quantity of water, add the goods and work them at a boiling heat. For scarlet add quercitron bark, for crimson, archil.

Lac-dye may be, however, prepared for dyeing, by submitting it, in powder, in a leaden vessel, to the action of sulphuric acid, in the proportion of not more than one part to two of the dye; and after the lac-dye is dissolved, the acid may be neutralized by carbonate of soda. With suitable mordants to the cloth or yarn, the colour may be then applied. Other processes for the employment of this dye are also adopted, but we have no room to detail them. (See Ure's Notes on Berthollet.)