cf the Oxide of Molyl/dena. ff 



blue and green folutions of tin were thofe which feemed moft 

 likely to accomplilh that end. 



C. The folution of molybdate of pota(h was mixed, in 

 certain proportions, with pure folutions of tin in muriatic 

 acid_, dilated in cold rain water. Shreds .of raw white wool- 

 len fluff, moiftened with boiHng water, were boiled for half 

 an hour in this mixture. The liquor was decompofed, de- 

 pofited the tin under the form of a grayifh powder, and the 

 refiduum all'umed an agreeable blue colour, which was com- 

 municated alfo to the (luff, but with a Ihade lefs pure. 



D. Not falisfied with this refult, M. Jaeger tried to pre- 

 pare the (luff, before it was immerfed in the bath of molyb- 

 dena, with different mordants ; fuch as fulphate and acetite 

 of alumine, diluted fulphuric and muriatic acid, acidulous tar- 

 trite of potafh, and others : but the refult did not anfwer the 

 objeft he had in view. He then thought it neceffary to 

 employ other means. 



E. A folution in excefs of molybdate of potafh was then 

 mixed with a faturated folution of tin ; the mixture was b,oiled 

 for half an hour in a retort, and was afterwards left at reft 

 for eight or ten days. After this time, the liquid, which at 

 firft was of a grayifli blue colour, was found changed into a 

 bright dark blue, and had depofited a large quantity of gray 

 oxide of tin. The liquid was decanted, and filtered through 

 double paper. 



I ft, This tinfture communicated a bright blue colour to a 

 flired of niuflin, which had been left in it for a quarter of an 

 hour after it had been diluted in two parts of water. 



ad, A flired of raw white woollen (luff was fo ftrongly co- 

 loured by this tinfture, that after ebullition for half an hour 

 it came out dyed of a pure faturated blue colour. 



As the tincture did not appear to be exhaufted of colour, 

 there were boiled in it for half an hour, each after the other, 



3d, A flired of woollen ftuff. 



4th, A flired of the fame kind. The two flireds acquired 

 a blue colour, decrcafing in intenfity. 



To afcertain how far the blue colour of the woollen cloth 

 could be fixed, a flired of ftuff was boiled for an hour in one 

 part of blue tinfture diluted with half a part of water. Its 

 colour was not darker than that of No. 2. 



The dyed flired was then cut into two part?, and one of 

 them was boiled for a quarter of an hour in the fame tinc- 

 ture, to which a little of the folution of tin had been added. 

 Its colour this time was more intcn'e. 



The colour in thcfe experiments had diflributed itfclf per- 

 feftly, and had united in fo intimate a manner with theficrcs 



VoL.XV. No. 57. C of 



