398 
PHARMACEUTICAL MEETING. 
and they are still unaltered. The statement made to the Pharmaceutical So¬ 
ciety by Mr. Richard Phillips, jun., at the evening meeting of October 9th, 
1844, and recorded in the ‘ Pharmaceutical Journal,’ vol. iv. p. 208, that solu¬ 
tions of the anhydrous perchloride of iron in water readily decompose on expo¬ 
sure to air, is obviously incorrect; solutions of the protochloride do so decom¬ 
pose, and I can only account for Mr. Phillips’s statement by supposing that pro¬ 
tochloride was present in the liquids on which he experimented. When 
anhydrous perchloride of iron is dissolved in water to form a solution of the' 
officinal strength just referred to, it has a specific gravity of 1*432 and contains 
40*5 per cent, of the salt, or 58 parts of solid perchloride in 100 fluid parts of 
the solution. This statement of the strength was confirmed by several experi¬ 
ments and by quantitative analysis ; it is very different to that given in the 
British Pharmacopoeia. In order, however, to compare this pure solution 
with others of similar strength, but which are impure, and therefore differing in 
specific gravity and consequently in percentage composition, it may be conve¬ 
niently described as a solution containing two ounces of metallic iron in ten fluid 
ounces, or twenty solid parts of iron in one hundred fluid parts of the solution. 
Solution of perchloride of iron is decomposed when boiled, hydrochloric acid being 
evolved. This is true whatever be the strength of the solution, and should be 
remembered by the chemist in using a neutral solution as a reagent in analysis, 
and by the pharmaceutist in evaporating the liquid with a view to concentra¬ 
tion. Sometimes the oxide first precipitated again dissolves as the solution cools 
this only occurs when much perchloride is still undecomposed, and is due to the 
solubility of oxide of iron in solution of the chloride. Anhydrous perchloride of 
iron is also readily soluble in ether and in spirit of wine, but the solutions are 
not stable ; in the course of a week or so they become opalescent and some basic 
chloride of iron is deposited. The ethereal solution undergoes the same decompo¬ 
sition in a few minutes if it be boiled ; and the alcoholic solution also, if it be 
heated under pressure. I find that a few drops of hydrochloric acid per ounce will 
prevent this decomposition. But perchlorideof iron and alcohol or ether decompose 
each other in another way when long exposed to the influence of light, and the 
reaction occurs whether the alcoholic solution be pure or contain water. Un¬ 
der these circumstances two-thirds of the chlorine in the salt remain with the 
iron, forming protochloride of iron, while the remaining third combines with 
the carbon and hydrogen of the alcohol or ether to form a volatile liquid of 
pleasant taste and odour, and which probably contains chloride of ethyl and 
possibly chloride of ethylene (C 4 II 4 ,, C1 2 ) and chlorinated derivatives of those 
bodies. The resulting almost colourless liquids were formerly officinal in the 
Pharmacopoeias of North Germany, under the name of “ Ethereal Spirit of 
Chloride of Iron ” and synonymous titles. It would seem that this reaction 
commences when the mixture of perchloride of iron and spirit or ether is made, 
as the solutions soon acquire the odour alluded to. The only other fact con¬ 
cerning solution of perchloride of iron to which I would now draw attention is 
that it is entirely converted into solution of pernitrate of iron if long boiled 
with excess of nitric acid ; it is also important to observe that solution of per¬ 
nitrate of iron is similarly decomposed if long boiled with hydrochloric acid. 
Properties of Protochloride of Iron .—Protochloride of iron also is soluble in 
water, alcohol, or ether, but the solutions are unstable in the air; they rapidly 
absorb oxygen, and yield a turbid mixture of perchloride and peroxide of iron. 
Aqueous solution of protochloride of iron is also partially decomposed on boil¬ 
ing, some hydrochloric acid escaping and oxide of iron remaining. But in addi¬ 
tion to this action, I find that the protochloride itself volatilizes, in an unde¬ 
composed state, in the vapour of water during the evaporation of its solution; 
and does so to an extent that precludes the possibility of preparing a solution of 
definite strength if ebullition occur during manipulation. Finally, protochloride 
of iron is far less soluble in strong hydrochloric acid than in water. 
