4^ On Argoiial Mercury. 



to confider, firfly that it forms almoft three fourths of thff 

 whole mafs ; in the next place, that the fpecific denlity of 

 the natural combination not only furpaifes, by a great deal, 

 the mean (pecific denfity of filver and liquid mercury, but 

 alfo that it is much more confiderable than that of the latter 

 metal, which is the heavier of the two. The fpecific gravity 

 indeed of the combination, calculated according to the for- 

 mula of- C. Haiiy, would l^e only X2*5448, fuppofmg the 

 mercury liquid, whereas itisi4Mi93; that of the iiiercury 

 js only I3'568i. 



A hundred parts of ar'gental mercury, folid and 



cryftallifcd, contain then of folid mercury - - 72*^ 

 Silver - - - - - - - 27*5 



100 

 Two other trials, made indeed with quantities lefs confi- 

 derable, gave abfolutely the fame proportioiis. 



The identity of the refults of the analvfis of this mineral, 

 its peculiar fpecific gravity, its faculty of cryllallizing, its 

 confifience, and all the other mineralogical charafters be- 

 lontrine: to it, evidently prove that it ought to be confidered 

 as a real chemical combination, pofleiling fixed and invarir 

 able proportions, and that it is with propriety that a parti- 

 cular fpecies has been formed of it in the mineralogical no- 

 jnenclature. 



It may be of. utility to remark here how improper the de- 

 nomination of native amalgam was to denote this mineral 

 fubftance. The name ftill employed in chcniiftry and the 

 arts does not denote a folid combination, but a pafle-likc 

 mixture, compofed of exceedingly fmall crvftals of argental 

 mercury, adhering to each other by the medium of a certain 

 quantity of liquid mercury. The confidence of the malTcs 

 of artificial amalgam is even very variable : it maybe in- 

 crcafed or diminillied at pleafure, fomciimcs by adding mer- 

 cury, fomctimes bv taking away a part of this metal, inter- 

 poled by means of a proper fiker, fuch as a piece of fliam- 

 .moy leather. It is the difficulty, perhaps, of feparating 

 entirelv the exccfs of mercury in the folid combination that 

 has occafioncd i> belief that filver and nrercury may be com- 

 bined in all proportions : this opinion feems to be as un- 

 founded as that in confequcnce of which argil, rendered 

 duclile bv the means of water, was confidered as a real 

 combination, the proportions of which might be indefinitely 

 varied. Il is proper to add, that at the common tempera- 

 ture argental mercury is always pcrfcdly folid, and befides 

 '-'■ ' that 



