MADDER LAKE.

365

Fustic-Carmine.

From fustic, yellow wood, or Cuba wood,—a dye-ware which will be moreparticularly noticed below, when we come to treat of yellow colouring matters,—a red dye may be prepared which is known as fustic-carmine. It is obtainedas follows :—The extra# of fustic is allowed to stand until the morine-lime isdeposited, when the clear liquid is evaporated to dryness. The residue isfinely powdered, and rubbed in a mortar with strong sulphuric acid. Fromthe brown-yellow solution a brick-red mass separates, which gives a splendidcarmine solution with a little ammonia or soda. It yields, with alum and alittle alkali, a red precipitate ; with protochloride of tin and chloride oibarium, a red precipitate ; and with nitrate of lead, a cherry-red.

This colour may be worth a closer examination than it has yet received.The raw material for its preparation may also be found by taking the depositwhich is found on splitting blocks of fustic, and purifying it by repeatedsolution in boiling water, and crystallising. It is then dissolved in moreboiling water with a little hydrochloric acid, and filtered. The clear liquor isset aside till a yellow powder subsides, which is then treated with sulphuricacid, as above.

PREPARATION OF LAKE COLOURS.

The increasing attention paid to the pigment-style in printing makes itnecessary for us to give a brief account of the preparation of lake colours.

A. Red Lakes.

1. Madder-Lake.—The following is a receipt for which the Society ofArts awarded their gold medal to Sir H. Englefield, the inventor:—2 ozs. troyof the finest Zealand (crop) madder are inclosed in a bag of fine, dense calico,large enough to hold three or four times the quantity. A pint of pure wateris poured upon it, in a Wedgwood or stone-ware mortar, and it is pressed andbeaten with the pestle—taking care not to rupture the bag—as long as anycolour can be expressed out of it. The liquid is then poured off. This treat-ment is repeated five times, with successive portions of water. The collectedliquid is then heated to near boiling, in a silver or stone-ware vessel, andpoured into a pint of boiling pure water, in which 1 oz. of alum—absolutelyfree from iron — has been previously dissolved. Into the mixed liquidfluid ozs. of a saturated solution of carbonate of potash is now graduallypoured, with constant stirring. The produdt is washed, first by decantation,and then on the filter, and carefully dried. The yield is £ oz.

Madder-lakes are at present generally made from charbon sulphurique , fromgarancin, or commercial alizarin. If garancin is used it is boiled in a block-tinpan with 20 times its weight of pure water, and alum, perfectly free from iron,equal to one-fourth or one-half the weight of the preparation of madderemployed. The boiling is maintained for some hours. It is then allowed tosettle; the solution, which is not quite clear, is drawn off; and the sameoperation is repeated three or four times with the former quantities of watera nd alum. The red extratSls thus obtained are filtered, as quickly as possible,through flannel, but are preferably not mixed together. From the first, moresaturated solutions, brown flakes are deposited in the course of a few days,