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XXVII. Analysis of some Salts of Mercury. By R. Phillips, 



F.n.S. L. Sf E. <$-c. 

 "ITTHEN two parts of mercury are heated, for a short time, 

 ' ' with three of sulphuric acid, some protosulphate of 

 mercury is formed; but if the heat be continued, the mercury 

 is converted almost entirely into bipersulphate, even before 

 the evolution of sulphurous acid gas ceases, or the whole of 

 the metal is dissolved. When this bipersulphate of mercury 

 is put into water it is decomposed, and a yellow precipitate, 

 formerly called turpeth mineral, is thrown down. 



This salt was, I believe, first minutely examined by Four- 

 croy {A?males de Chimie, torn. x. p. 109.), and according to his 

 analysis, it consists of 



Sulphuric acid 10 



Mercury 76 



Oxygen 11 



Water 3 



100 

 MM. Braamcamp and Sequeira {Ann. de Chimie, tom. liv. 

 p. 123.) give as the result of their analysis, 



Sulphuric acid 15 



Peroxide of mercury 84*7 



Loss, attributed to moisture 00'3 



100-0 

 Dr. Thomson {System^ vol. ii. p. 660.) observes, that sup- 

 posing it to be a compound of 1 atom acid + 1 atom per- 

 oxide, its constituents will be 



Sulphuric acid 15*62 



Peroxide of mercury 84*38 



100-00 

 In his Attempt, &c. (vol. ii. p. 403.) also Dr. Thomson con- 

 siders this to be the true composition of this salt. Wishing, 

 however, to determine its nature, as well as that of the salt re- 

 maining in the solution from which it is precipitated, I put 

 200 grains of bipersulphate of mercury into about a quart of 

 cold water; the yellow sulphate precipitated weighed 141*1 

 grains; the solution was then heated, by which 8*4 grains 

 more were obtained; afterwards sulphuretted hydrogen threw 

 down 14-5 of bisulphuret of mercury. 



To ascertain the composition of the yellow sulphate, I heated 

 100 grains in a solution of soda; the peroxide of mercury 

 separated weighed 86*9 grains ; to the solution, after super- 

 saturation with muriatic acid, muriate of barytes was added, and 



37*3 



