risian perfumers extracted their rouge from the vegetable kingdom, and that they would all apply to the academy for certificate, it was thought proper not to pronounce upon M. Dupont's rouge till all the other sorts of rouge sold in Paris, were likewise examined: Messrs. Lavoisier and Jussieu, jun. were therefore appointed to make the necessary experiments, to ascertain the constituent parts of them all. From their report it appears, that the art of preparing red paint from the vegetable kingdom, is not a new discovery, but had been known long ago to the ancients. Theophrast mentions a root, from which a red colour was extracted, to rouge the cheeks. Pliny also notices a certain root (the produce of Syria), that was used for the same purpose, and also for staining wool. Those roots were probably similar to our madder and alcanna (ligistrum). When the Italians, during the reign of Catharine de Medicis, brought the use of rouge into France, they at the same time taught the mode of preparing it: this was similar to what is now practised. Well-dried wild saffron is put into a linen bag, and laid in a running stream of soft water, or in standing water, often changed; a person with wooden shoes treads the bag, till the water passes thro' it quite clear, and not the least vestige of a yellow tinge is perceived; after this, a sixteenth or twentieth part of soda, or potash, is added, and soft, pure, cold water is poured upon it, which will obtain a yellowish liquor; the colouring matter being precipitated with lemon- juice, produces a red sediment: this operation is repeated, till all the colour is extracted. It is this precipitate which is mixed with very fine pulverized talc, and made with lemon-juice into a paste, with which small pots are filled for sale.
Though this sort of rouge is very common in commerce, yet there is another, less fine and brilliant, but cheaper: this is generally sold in small parcels. This rouge is made of carmine, which is extracted, as is well known, front cochineal: here also the colouring matter is mixed with the talc and some lemon-juice, and afterwards dried. There is no doubt but that the high price of the colouring matter extracted from the wild saffron and the carmine, has induced some people to substitute cinnabar (vermilion;) and there exist some old recipes, in which cinnabar, either wholly or in part, is recommended: but rouge of this sort may produce very serious consequences, and its use cannot be too carefully avoided. It will not be amiss if we indicate the means how to discover if rouge contains any mineral substance.
The colouring matter extracted from the wild saffron, possesses, like almost all vegetable colours, the property of being soluble in spirit of wine: if therefore spirit of wine is poured twice or three times over rouge of this description, the colour will be dissolved, and the talc will remain white. This single experiment will ascertain whether the rouge is extracted from vegetables only, cochineal and carmine are not acted upon by spirit of wine, and this shews at once that the rouge is not of the vegetable kingdom. But cochineal and its extract are soluble in alkaline liquors; if therefore a very weak solution of
