RESEARCH FOR ARSENIC AND ANTIMONY. 291 
were all sold as pure , and, in many instances, were specially 
stated to be free from arsenic. 
“ Of these samples, eight were said to be electrotype copper; 
and, from their appearance, I should say they were. Four 
out of the eight were said to have come from Germany. 
“ Some of these samples I had from friends, and the re¬ 
mainder were purchased in London from different sources of 
high respectability. 
‘ 4 In every one of these samples l found the presence of 
arsenic, higher in some than in others, but unmistakeable in 
all. I do not say that the arsenic was in such quantities as 
in ordinary circumstances to mislead an experienced person 
in detecting arsenic in a substance by Reinsch's test; still in 
fluids containing oxidizing acids, and w hen it w r as requisite to 
detect minute quantities of arsenic, I think the quantity of 
arsenic in even the purest of these eight coppers w r ould in¬ 
terfere with the test. 
“ Of the remaining twelve samples, some w’ere purchased in 
London from undoubted sources of respectability, others w ere 
obtained through friends at Bristol, Liverpool, Edinburgh, 
and Glasgow. Two out of the twelve were copper-gauze; the 
remaining ten w T ere foil of different thicknesses. 
“ In all these samples of copper, arsenic was present in dis¬ 
tinct quantity, and, as in the electrotype samples, there w r as 
a variability as to quantity : but the sample most free from 
arsenic ; contained much more than the most contaminated of 
the electrotype samples. I am of opinion that some of the 
samples were so impure from the presence of arsenic, as even 
to mislead an experienced person, when testing for this sub¬ 
stance under ordinary circumstances. 
“ I remain, &c., 
tc August 13th, I860. “Dugald Campbell. 
" Dr. A. S. Taylor.” 
If these facts be admitted, the inquiry naturally follows—Is 
there any risk in employing copper containing arsenic, for 
separating this substance in cases of poisoning ? The answer 
may be anticipated. There is no risk, unless the copper, 
during the process, is brought to a state of solution ; and of 
this fact the operator is immediately informed by the disap¬ 
pearance of the metal and by the liquid acquiring a deep- 
green colour. Hence, w r hile the negative results which the 
process so frequently furnishes afford an unquestionable 
proof that the copper may be used with safety, the operator 
has clear evidence when there is risk, by the solution of the 
copper in the acid liquid. If the copper employed is unal- 
