iVi?w ProMfsfor makitig Cinnnhar in the Humid Way, ,3j| ■ 



than on the firft day. In order to afcertain whether this phenomenon was owing to fimple 

 drying, or to heat, I placed a pinch of the lighted colour on a fmall piece of glafs, which 

 I heated very flroBgly with a candle. ] then enjoyed a very beautiful fight, of which the 

 j:efult,gave me the greateft p!e?fure. The powder of cinnabar became brown in. an inftant, 

 and foon afterwards nearly blaclc, or rather of the deeped violet grey; but when, on the 

 fuppofition that I had fpoiled my cinnabar, I threw It from the glafs upon a paper, I was 

 very agreeably furprifed -to obfc-rve it in the twinkling of an eye pafs through all the tranfi- 

 tions from obfcure violet -to a beautiful carrtiine red, and to obferve more particularly that 

 this colour had acquired the nrc and brilliancy which was wanting before the experiment. 

 As an objcft of COmparifon, I had fome cinnabar of commerce, of which the pond, or forty 

 pounds (Ruffian), is fold at Petcrfburgh for eighty roubles. I put a pinch of this on the fame 

 ,ilip of glafs, and fvbjc^ed it to .the fame treatment. The colour fpeedily became black, 

 arrd, after Cooling, acquired a very bad deep brown tinge, refembling umber of a bad quality, 

 without recovering its original red. I repeated this experiment in a larger way with the 

 .fame fuccefs,and by that means afcertained a method of giving in general much brilliancy 

 to my cinnabar, and of producing the mod brilliant carmine tint. This heat, which muft 

 be very drong, requires, neverthelefs, to be condu£led with much prudence. The cinna- 

 bar mud not fume, nor exhibit grey globules on its furface ; for in thefe cafes it would be 

 eflc6lually fpoiled. This phenomenon feems to prove a decompofition and abforption of 

 air; but it remains to be fliown whether it be hydrogene, oxygene, or azote, which the cin- 

 nabar takes up in this experiment. 



Thefe conditute the mod eflential fafls I have obferved with regard to the production 

 of cinnabar in the humid way. I intend, when time permits, to give a continuation of this 

 memoir. 1 have already made fome new experiments, which, though they may not yet 

 promife any advantage to the manufadurer in the large way, may be ufeful to the painter 

 and intereding to the chemid. 



The black liquor which I at fird decanted from my cinnabar, depofited a fmall portion 

 of ethiops, not furcompofed. I mud add in conclufion, that the manufacturer in the large 

 way mud of courfe fubmit his colour to feveral elutriations, colleft the depofitions in feve- 

 ral vcffels, and afterwards mix his colours when dried. It would be likewife neceflary for 

 the finer forts, to provide a furnace, in which either the carmine colour or the Fequifite fire 

 and brilliancy may be given. A furnace of this kind may very, eafily be contrived, and it, 

 would be unnecedary to defcribe its condrudlion in this place. It is my widi, that the fo- 

 clety to whom 1 have the honour to addrefs the prefeut memoir will confider it as a proof 

 of my refpe£l and gratitude. By admitting me into the number of its members, a new 

 proof is afforded of its indulgence to the weaked efforts in favour of the fciences and na- 

 tural hidory. The excellent difcovery of Mr. Kirchoff has led me to afcertain fome new 

 fafts, of which I am defirous that commerce diould have the advantage ; but the honour of ■ 

 the difcovery belongs to him, and deferves to be the more infifted on, as his modedy is no : 

 lefs CDnfpicuous than his knowledge. 



U. On 



