MILK OF SULPHUR. 537 
According to M. E. Latour, the addition of sugar preserves this salt from 
alteration. 
He then gives a form for crystallizing the sulphate with sugar. 
There appears to be a very simple and effectual means for preventing oxi¬ 
dation of this salt,—by putting a small lump of camphor, screwed up in tissue- 
paper, into the bottle with the ferrous sulphate. 
It is now three months since I adopted this plan ; the bottle is frequently 
opened, yet the salt is as free from oxidation, and its aqueous solution is as 
clear as it could have been before the salt was crystallized. I may also add that 
it stands the other tests of the Pharmacopoeia. 
MAGNETIC OXIDE OF IRON. 
TO THE EDITORS OF THE PHARMACEUTICAL JOURNAL. 
Gentlemen,—At the last meeting of the Society I gave a note on this subject, 
and said, or intended to say, something different to what I am reported to have 
said. In the first place, I stated nothing about “ ferrous hydrate of iron.” I 
mentioned u ferrous hydrate,” and “ the lower hydrate of iron,” but I do not 
think I was guilty of the tautology implied in the phrase u ferrous hydrate of 
iron.” In the next place, the error is ascribed to me of considering that in the 
preparation of magnetic hydrate of iron, 11 the iron salts are added to the alkali 
and not the alkali to the iron salts, in order to at once get the mixed or com¬ 
bined hydrates as a precipitate.” Now I said that this result followed, but 
made no reference to the chief reason of adopting the one order of mixing, 
rather than the other. This reason was well explained in the discussion, but it 
was no part of my object to refer to it; indeed, I believed it was well known. 
r Ihe point to which I desired to give prominence was this,—Is magnetic hydrate 
of iron as magnetic, when made by mixing together ferric and ferrous hydrates 
after each has been precipitated, as when made by precipitating the hydrates at 
the same instant? My experiment showed that the article was as magnetic in 
the former as in the latter case. It is remarkable, I think, that two substances, 
solid, and closely allied in chemical properties, should combine on coming into 
mere contact. In the third place, I intended to state, that as the combination 
of the two hydrates was progressive and not complete until the lapse of twenty- 
four hours, the fact was a good illustration of a matter that has occupied some 
attention lately, namely, the influence of time on chemical change. 
I am, etc., 
John Attfield. 
MILK OF SULPHUR. 
TO THE EDITORS OF THE PHARMACEUTICAL JOURNAL. 
Dear Sirs,—My attention being accidentally called to the impurities in a 
sample of milk of sulphur we had just received from one of the London houses, 
I tested a portion of it by heating 50 grs. in a crucible, and on weighing the 
residue, and adding one-fourth for water (CaS0 4 ,2LLO), I found that the 
quantity of impurities amounted to 52 per cent, of the whole. Wishing to see 
if my brother druggists were subjected to the same imposition, I procured a 
sample from five others. One sample alone was pure, the others containing 56, 
62, 70, and 72 per cent, of sulphate of calcium. 
Cannot this fraud, which appears to be so persistently practised, be put an 
end to ? Some means, I am sure, should be adapted to this wholesale adultera- 
