2 Ordinary Procefs for mahng Cinnahar by Sullimation. 



'beeH.'bfetain?3'5r'e too \ven*'knbwn,antf It would te fuperfluous to mention them liere. 

 But as the various inconveniences of fublimation, grinding, and the other preparations of 

 this colour, are frequently prejudicial to the health, and fonietimes expofe the lives of the 

 ■workmen to inevitable danger; and as the lofs of veflels and the expence of fuel are but too 

 frequently fek by thofewho nndertake this fabrication ; it is evident that a method of ob- 

 taining cinnabar fubjedl to none of thefe inconveniences, and requiring little of expencc 

 excepting the firlt cod: of the mercury, rauft become truly valuable to this branch of in- 

 duftry. We' are indebted to Mr. KirchofF, a young chemift of the greateft hopes, who is 

 attached to the pharmaceutic department, for the firft difcovery of a method no lefs in- 

 geHicus than obvioufly of gxeat probable advantage to commerce. His claim in thisTefpe£t 

 is beyond controverfy. For, though cinnabar has been obtained in the humid way by 

 means of volatile liver of fulphur, there never could have been any hope of applying that 

 method to the purpofeg of trade, on account of the heavy expence of the re-agent. But 

 the intermedium ufed by Mr. KirchofF promifes, on the contrary, all the advantages 

 which the mod fcrupulous calculation can require, and, when brought to pexfe£tion, will 

 probably caufe the method of fublimatlon to be' abandoned by all who may be defirous 

 of engaging in this branch of commerce, without expofing themfelves to unncceffary 

 rifque. 



I (hall proceed to lay before this illuftrious Society all the details of the procefs of 

 Mr. KirchofF, as, well as the inconveniences which have hitherto prefented themfelves. 

 It is with great pleafure that I avail myfelf of this opportunity of doing juflice to the 

 merits of this chemift, which have been hitherto concealed by his excefs of modefty ; and I 

 have annexed to this memoir my own proper experiments, which have enabled me to re- 

 move feme of the principal difficulties which KirchofF met with in his work. I have no 



in Crell's Journal, of which an abftraft is inferred in the fourth volume of the Annales de Chimie, page jj. 

 It is concifely as follows : (i.) Ethiops mineral is prepared by combining 150 pounds of fulphur with loSo 

 .pounds of pure mercury, by a moderate heat, in a fiat-bottomed polilhed iron vtflel. 2. The ethiops, after 

 flight pulverization, is put into earthen bottlas, each capable of containing a quart of water. 3. Three large pots 

 ©r fublimatory veffcls, made of very pure clay and fand and luted, are then taken and placed upon iron circles 

 over furnaces, conftrufted in fuch a manner that tlie flame of the fuel, which is turf, circulates freely round 

 the veffels to two-thirdsof their height. 4. When the veflels are red-hot, a bottle of the ethiops is poured. into 

 the hrft, another into the fecond, and another into the tbitd. In theTubfcqucnt progrefs of the operation, two, 

 three, and perhaps more bottles may be poured in at a time ; but this depends on the ftrength of the inflam- 

 ination exhibited by the ethiops after its introduftion, the flame of which fometimes rifes to the height of 

 four and even fix feet. When this is a little diminiflicd, the mouth of the veffel is covered with a plate of 

 iron, one foot fquare and an inch and a half thick, which perfeftly clofes it. In this manner during thirty- 

 four hodrs the whole of the prepared matter is introduced into the three pots ; that is to fay, into each pot 360 

 pounds of mercury and 50 of fulphur. 5. The fire is then kept up till the fublimation is completed, and after- 

 wards fuflfered to go out ; which requires 36 hours from the time of the complete charge. It is judged to have 

 the proper intenfity, when, upon taking off the cover, a brifk flame appears, but does not rife more than three 

 or four inches out of the pot. 6. During the hft 36 hours, the mafs is ftirred ^very quarter or half hour 

 with an iron rod. 7. When all is cold, the veffcls are removed by means of the iron circles, which prevent 

 their breaking. The cinnabar is taken out by breaking the veffel. Each pot conftantly affords 4,00 pounds of 

 cinnabar, the lofs of original weight in each being 10 pounds. The cinnabar does not attach itfelf to the 

 plates of iron, becaufe they are continually taken off excepting towards the end, when the velTels are left un- 

 touched. Thefe plates are not in the leafl corroded. N. 



Other 



