LIQUOR PERM PERCIILOKIDI. 
► O 
>o L 
■cause of accident. If this distinction vrere more strictly insisted on, I be¬ 
lieve we should less frequently see reports of “ Death by Poison.” 
Richmond , October 19, 1864. 
LIQUOIl FEBI1I PERCHLOBIDI. 
TO THE EDITOR OF TIIE PHARMACEUTICAL JOURNAL. 
Sir,—In a lecture on iron bj T Mr. E. Davies, F.C.S., an abstract of which 
appeared in the June number of the Journal, the lecturer, while explaining 
how “ the perchloride is best prepared,” is reported to have said:—‘‘‘The 
process given in the Pharmacopoeia is not good, as a sample prepared in strict 
conformity to its directions gave a dark liquid containing protosalt and nitric 
acid. On heating more strongly, the solution became muddy from formation 
of a subsalt.” 
The next number contained a letter from Mr. A. Utley, endorsing the above 
statement. He found, however, “ that] if twelve instead of ten ounces of hy¬ 
drochloric acid (sp. g. 1T7) are used ... a liquor is obtained which will an¬ 
swer the tests given,” etc.,—the reason being that “ymofochloride of iron 
requires half as much more chlorine as it already contains to convert it into 
perchloride.” 
The process in my hands has answered better, and I do not regard the 
addition above suggested as an improvement. 
The quantity of chlorine contained in the hydrochloric acid of the formula 
is nearly 50 grains greater than that required to convert the whole of the iron 
into perchloride. Put as this is only a scanty surplus, the necessity of avoid¬ 
ing loss as far as practicable is obvious. The nitric acid is in considerable excess, 
as according to the equation, GFeCl T 3HC1 + H0 5 — 3Fe 2 Cl 3 \ 3HO -f H 0 2 , 
-scarcely 41 fluid drachms of it take part in the reaction. The temperature 
required to complete the decomposition is so low towards the end of the pro¬ 
cess in question, that it seems hardly likely a “ dark liquid containing proto¬ 
salt*” should result from failure in this respect. 
To give an experiment:—2 ounces of flue bright iron binding-wire, cut 
into short lengths, were introduced into a long-necked flask and treated with 
10 ounces of hydrochloric acid of correct strength , diluted with 5 ounces of 
water, the flask being partially closed by a loosely-fitting stopper. After the 
lapse of twelve hours, a “ gentle heat ” was applied to complete the solution 
of the metal. The liquor was now poured into a capacious evaporating-dish, 
the nitric acid diluted with the rinsings of the flask added, the whole heated 
sufficiently to perfect the decomposition and then evaporated to the proper 
bulk. The product possessed the characters ascribed to it in the Pharmaco 
poeia, except that it was not quite “ without smell.” 
A small quantity of this liquor diluted and heated was mixed with a slight 
excess of ammonia. The precipitate washed until The washings were free 
from chlorine, then dried and ignited, gave Fe 2 0 3 30‘30 grains. To the filtrate 
and washings acidified with nitric acid, solution of nitrate of silver was added,, 
The precipitated AgCl, alter washing, drying, and heating to incipient fusion, 
weighed 162’34 grains. These weights give the proportion of 56 iron to 
106‘03 chlorine, and show a deficiency of the latter in. the whole batch of 
rather more than 7grains, which would leave about 4 grains of iron “unpro¬ 
vided for.” To another accurately measured portion of the liquor, diluted 
and heated, alkaline solution of known strength was added from a burette to 
.aint alkaline reaction. Deducting the quantity required for combination 
