294 
RESEARCH FOR ARSENIC AND ANTIMONY. 
may be occasionally met with in organic liquids. A grain of 
each of these salts was dissolved in two drachms of diluted 
hydrochloric acid, in the proportions used for the precipitation 
of arsenic (1:8). The solution was brought to the boiling 
point, and boiled for a few minutes in contact with a slip of 
polished copper. No copper was dissolved in any one in¬ 
stance, and the metal retained its lustre. On adding a 
minute portion of arsenic to the liquid, the metallic copper 
was speedily coated, and traces of a salt of copper were now, 
for the first time, found in the liquid. When to a similar 
quantity of acid liquid, in which copper was immersed, a 
fragment of chlorate of potash was added, there was an imme¬ 
diate solution of a portion of the metal; a fact rendered 
evident by the production of a green colour, and by the appli¬ 
cation of the usual tests for copper to the liquid. 
While the presence of a sulphate, nitrate, chloride, or phos¬ 
phate does not affect the process, so long as a properly diluted 
acid is employed for a proper time, it was found that an 
alkaline chlorate, even in small quantity, caused a rapid 
solution of the copper, and in propertion to the amount of this 
solvent action, a liberation of arsenic from the arsenicated 
copper. Owing to this chemical action of a chlorate on 
copper, it has been contended that Reinsch’s process ought 
never to be employed when such a salt is present. Mr. 
Herapath affirms that “ Reinsch’s process is not applicable 
where nitrates or chlorates are present. 5 ’ 1 With respect to the 
nitrates, it admits of distinct proof that they present no 
objection when a properly diluted acid is used ; and with 
regard to the chlorate, the process is objectionable, provided 
pure copper be used. The operator, in using copper free 
from arsenic, has only to saturate the liquid with the metal, 
and the last portion of copper put into it will effectually 
remove the whole of the arsenic, as well as any antimony 
that may be present. It is a good method of detecting 
minute traces of arsenic or antimony in copper; and one free 
from all objection, provided the hydrochloric and the 
chlorate are pure. The only circumstance which would 
render Reinsch’s process inapplicable to the separation of 
arsenic in the presence of a chlorate is the use of copper con¬ 
taining arsenic, like the No. 13 wire or the dial-plate or foil, 
as it is commonly sold. It is only the analyst, who has 
habitually and knowingly used arsenicated copper, who can 
treat the presence of a chlorate in an organic liquid as a 
serious obstacle to the employment of this process. 2 
1 Letter in the ‘Lancet,’ September 3, 1859, p. 248. 
3 In the Smethurst case, arsenic was deposited on a piece of copper 
