New Procefs In the Humid H^ay. 3 * 



■other claim than that of having endeavoured to render his difcovcry. as; ufeful-srs poflible i«i'i 

 technical chemilts. > ' 



Mr. KirchofF, who has operated in the fmall Way only, gives the following proportions for': 

 the produ£lion of cinnabar in the humid way: 



Three hundred grains of' mercury are triturated in a velTfl or cup of porcelain, with , 

 68 grains of flowers of fulpliur,. until an ethiops is accurately produced, in which no meti ' 

 taUio glob»les;can be perceived by the magnifier. As this degree of union of' the nief- ' 

 cury and fulphur cannot be obtained when both are perfeftly dry, Mr. KirchofF adds »^ 

 few drops of a folution of cauftic vegetable alkali ; and when the union of the mercury antf ' 

 ;fulphur is complete, he adds to the mixture a foliitipn of 160 grains of the fame alkali 

 diflblvedin an equal quantity of water. He heats the vefl'el containing thefe ingredients 

 over the flame of a candle, and triturates without interruption during the heating with a' 

 gla.fs pellle. In proportion as the liquid evaporates, he adds clear water from time tdo 

 time, fo that the ethiops may be eonftantly covered to the depth of near an inch. For the 

 above quantities, it is requifite to continue the trituration nearly two hours ; at the endo 

 ■of which time the mixture begins to change from its original black colour to a brown, ' 

 ■which ufually happens when a large part of the fluid is evaporated. From this firfl mo- 

 ment the tranfition from brown to red is very rapid. No more water is then to be added, 

 but the trituration muft be continued without intermiflion. When the mafs has acquired 

 the x:onriftence of a jelly, the red colour becomes more and more bright with an incredible 

 degree of quicknefs. This is the moft important point of time for the fuccefs of the ope- 

 ration. For, if the heat be not continued long enough, the colour will not acquire the ut- 

 moft degree of beauty ; and on the contrary, if it be continued only two feconds too long, 

 the fine red of the cinnabar pafles as quick as lightning to a dirty brown. Mr. KirchofF, 

 as well as Mr. Lowitz, who has repeated his experiments, could not fucceed in amending 

 this brown colour ; which confequently renders the fuccefs of the operation very precari- 

 ous. This inconvenience is produdlive of another ; namely, that it is nearly impolTible, at 

 the inftant of the produftion of the colour of the cinnabar, to make any obfervation of the 

 quality of the tint. For the colour of the liver of fulphur mafks that of the cinnabar ; 

 fo that in fome inftances the moft beautiful red is obtained, and in others a colour 

 inclining to orange, which, though bright and vivid, is not the tinge required in this 

 produfl. In one of his experiments, Mr. KirchofF obtained a cinnabar which abfoluteljs* 

 pofTeflTed the colour of carmine ; but he had this good fortune only once, when he had" 

 no expectation of fo beautiful a product, and did not therefore note the attendant cir- 

 cumftances. 



This is nearly the whole detail of the experiments hitherto made by Meflrs. KirchofF 

 and Lowitz. The cinnabar they obtained ftill exhibited mercury in the metallic (late, 

 which it was rather difHcult to get rid of, and did not appear until after the filtration of 

 the liver of fulphur, and the edulcoration and drying of the vermilion. 



I fhall now proceed to relate what I have done refpedling this objedt, principally with a 

 view to facilitate the manufa£turing in the large way, the reftoration of the cinnabar which 

 had afFumed a brown colour inftead of red, and the certainty of the tint in mafFcs fome- 

 what confiderable. I am very far from being content with the fuccefs of my experiments ; 

 but I think I have at leaft difcovcred great part of the theory of the operation, and that in 



B 2 pradlice 



