308 BUNSEN ON THE CACODYL SERIES. 
2. Substance analysed *. 0+. "4% +. 13245 orm 
Water and chloride of mercury . . . 0°2140 ... 
Chloride of mercury * <9... EOI 
Carbonic acid.) |.) ws 0°3000 ... 
I employed a method to detamaine the mies” which has 
great advantages over that by the moist way, and as it is more 
accurate, deserves attention. 2°082 grm. of the substance with 
a mixture of lime and chlorate of potash, were poured into an 
ordinary combustion tube, which had the open end extending 
some inches out of the furnace, and at the other end a piece of 
chlorate of potash. The combustion was conducted with the 
same precautions as that in use in ordinary organic analyses. 
After the escape of gas had ceased, that end of the tube which 
contained the metallic mercury was cut off, dried and weighed, 
from which it appeared to contain 1:0593 grm. of mercury. The 
experiment was repeated with 1:142 grm. of the substance, and 
0°579 erm. of mercury was obtained. 
The amount of arsenic was determined in this way, viz. 0°8584 
grm. of the substance was oxidized in the combustion tube by 
a mixture of two parts chlorate of potash and one part lime, and 
the mercury separated at the same time. The contents of the 
combustion tube were dissolved in muriatic acid, and yielded 
0:3745 grm. of sulphuret of arsenic free from mercury. 0°327 
grm. of this precipitate was then dissolved in fuming nitric acid, 
and left 0:004 grm. behind; the solution afforded 1:2953 grm. 
sulphate of barytes. This experiment gives 19°25 per cent. 
arsenic. As chloride of silver is not quite insoluble in a liquid 
containing mercury, I passed 2°082 grms. of the substance over 
heated lime, in the usual way, to separate the mercury. This 
lime was dissolved in acetic acid, and afforded 1°450 grm. chlo- 
ride of silver, and 0°0528 grm. silver on the filter. 
These results collected make the composition of the substance 
to be as follows :— 
If II. Calculated. 
Carbon .. C, 6°23 6°26 6°18 
Hydrogen . Hy 1°76 1°76 1°55 
Arsenic . . As, 19°25 ee 19°43 
Oxygen .. O 3°94 “- 2°06 
Mercury. . Hg, 50°80 50°70 52°33 
Chlorine. . Cl, 18°02 oF 18°30 
100°00 100°00 
