on the Colouring Matter of Cochineal. 317 



colourlcfs. The ftnff, after it was waflied and driedj retained 

 a bright ?nordore colour. 



Exp. III. A neutral folution of cobalt in fulphuric acid 

 •was added to the tincture of cochineal. The tinfture aflumed 

 a darker colour, and a violet precipitate was depofited. A 

 piece of ftuff impregnated with this folution of cobalt, and 

 then dipped in tindture of cochineal, acquired a laturated 

 violet colour. 



Exp. IV. A neutral fulphuric folution of uranium gave 

 with tiu(Slure of cochineal a precipitate alrnolt black; but 

 when a piece of ftuft" was dipped in the fame folution, and 

 then dyed with tindure of cochineal, it aflumed a very agree- 

 able gravilli colour inclining to green. 



Exp. V. A folution of cobalt in nitric acid, treated in the 

 fame manner, gave the fame refults; but with this differ- 

 ence, that the colour on the (luft' was a little brighter. 



E.vp. VI. Fifteen grains of tungdic acid were put into a 

 glafs vefll'l, and fix ounces of diltilled water being poured 

 over it, the whole was reduced bv evaporation to four ounces. 

 The folution aflumed a turbid' afpedl, and a blueifh white 

 colour. A part of this folution being poured into tinfture 

 of cochineal, communicated to it a bright violet colour. A 

 piece of kerfeymere, being boiled for three minutes in this 

 folution, was immerfed in the warm tinfture of cochineal : 

 when taken out it was of a Wight ponceau (poppy) colour. 



Exp. VII. Fifteen grains of concrete molybdic acid were 

 diflcilved in water as above. It diflfolved entirely, and the 

 folution became clear and tranfparent. Being dropped into 

 the tinclure of cochineal, a dark violet precipitate \yas ob- 

 tained. A piece of kerfeymere boiled in the acid folution 

 aflTumed a colour approaching to bright green, which, when 

 tbe fluff was dried in the fun, pafled to'a gray inclining to 

 bright blue. A piece of kerfeymere impregnated with the 

 fame folution, being immerfed in warm tinfture of cochi- 

 neal, afllmied a very agreeable violet colour. 



£.i/». VIII. Arfenic acid, being mixed with the tinftnre 

 of cochineal, the dark red colour of the latter was transformed 

 into yellowifli red, but without anv dcpofit being formed. 

 A piece of kerfeymere was then boiled for three minutes in 

 a very dilute folution of the fame acid, and the ftufl thus 

 prepared was immerfed in warm tindlure of cochineal. Tlie 

 fluff immediately aflumed a bright fcarlet colour inchnitig 

 flrongly to yellow. Dryings and, in particular, preflingwuh 

 a hot iron, made this colour lofe u little of its brightnels, and 

 ctufcd it to become darker. 



5 E.vp. IX. 



