Analysis. 
103 
Art. xxiv.— analysis of a white powder found in a 
HORSE TROUGH, SUPPOSED TO BE POISON. By P. T. Tyson and 
Wjj. R. Fisher, Associate Member of the Philadelphia College of Pharmacy. 
The quantity submitted for examination is about one grain. 
It is white, not granular, and apparently free from organic 
matter. The quantity found and sent is so small that but a 
very minute portion can be allowed for experiment. It has 
not the appearance of arsenic or corrosive sublimate, but 
rather that of a vegetable powder ; to determine promptly 
whether the latter were the case, a small speck of it was 
heated on a platina spatula, over a spirit lamp ; copious 
white fumes were given off, and a very minute speck of car- 
bonaceous matter left ; this at once determined the belief of 
its being a mineral substance, mixed with a small proportion 
of vegetable matter. 
A regular series of experiments was now commenced, as 
follows : 
About one-third of the whole quantity was mixed with 
charcoal and carbonate of soda, and exposed in a tube to the 
heat of a spirit lamp, for reduction. A white crystalline sub- 
limate was found lining the tube, invisible by transmitted 
light ; only seen by reflection. It was evident from this that 
there was no arsenic. The appearance indicated mercury. 
2d. A fresh portion of the powder was dissolved in a 
watch glass, in muriatic acid ; the excess of acid being neu* 
tralized by caustic potassa ; hydrosulphuric acid was added, 
and a black precipitate fell — bisulphuret of mercury. 
3d. The reducing tube being divided just above the flux, 
and the lower end of the superior portion sealed, one or two 
drops of nitric acid was poured into the tube, and the sub- 
limate (No. 1,) was dissolved; about twelve or fifteen minims 
of water were added, and a complete solution formed. This 
solution, acted on by the following reagents, gave the an- 
nexed results : 
A. One drop, placed on the back of a gold watch, and a 
galvanic circle formed by the blade of a penknife, gave a 
Vol. I— No. 2 14 
