206 Mr. R. Phillips's Analj/sis of some Salis of Mercuri/. 



37'S grains of sulphate were precipitated, equivalent to 12*6 

 of sulphuric acid One hundred grains, therefore, yielded of 



Sulphuric acid 12'6" 



Peroxide of mercury.' 86*9 



Loss *5 



100-0 

 I ascertained the quantity of peroxide of mercury also, by 

 decomposing the salt with sulphuretted hydrogen; 100 grains 

 gave O^'S of bisulphuret of mercury = 88*2 of peroxide. 

 Taking the mean of these experiments, the salt consists of 



Sulphuric acid 12*6 



Peroxide of mercury 87*5 



100-1 

 I therefore consider the yellow sulphate of mercury, as a 

 subpersulphate constituted of 



Three atoms of sulphuric acid (40x3) = 120 or 12-2 

 Four atoms of peroxide of mercury (216x4)= 864 87'8 



984 100-0 

 or it may be regarded as consisting of 



Two atoms of persulphate of merciu'y (80 + 432) = 512 

 One atom of dipersulphate (40 + 432) = 472 



984 

 This however is so unusual an atomic constitution, that I 

 have not admitted its existence until after repeated analyses ; 

 it will be observed, that if we add the oxygen to the mercury, 

 in Fourcroy's analysis, the resulting peroxide will amount 

 to 87, with which the results of my experiments very nearly 

 agree. 



With respect to the sulphuric acid and the peroxide of mer- 

 cury remaining in solution, and which have been supposed to 

 constitute a peculiar supersalt ; it may be observed, that when 

 four atoms of bipersulphate of mercury are acted upon by 

 water, a compound of three atoms of acid and four atoms of 

 oxide is precipitated, while five atoms of sulphuric acid re- 

 main in solution : this acid, however, prevents the decompo- 

 sition of the whole of the bipersulphate by dissolving a por- 

 tion of it; the quantity remaining in solution depends, to a 

 certain extent, upon that of the water employed; thus, when 

 using a quart of water, as in the above related experiment, 

 nearly 150 of the yellow subpersulphate were precipitated 

 from 200 of the bipersulphate, but when only half the quan- 

 tity of water was used, 1 55 were obtained from an equal 



weight : 



