62 REMARKS ON THE ACIDS OF THE BRITISH PHARMACOPEIA. 
Of these blood-stains, all that I am prepared to state at present is, that the 
first or colourless sublimate is formed at a temperature so low as to preclude the 
idea that it is a result of decomposition ; and that the second, though formed at 
a heat sufficient to develope new products, differs in colour from the deposits 
which I shall describe in my next communication as smoked sublimates, while it 
resembles in this element of colour the old blood-stain from which it is procured. 
Perhaps, when my fourth paper is ready, I may be able to give some further 
account of these blood-sublimates. My object in speaking of them now, instead 
of waiting till I know more about them, is to complete the description of the 
test of sublimation as far as it has to do with the substances susceptible of being 
sublimed. We are nowin a condition to state that sublimation, at temperatures 
obtainable with the spirit-lamp, is a property shared by such inorganic bodies 
as arsenic and mercury, by such organic bodies as the alkaloids and glucosides, 
and by such animal matter as blood and the constituents of the urine. 
REMARKS ON THE ACIDS OF THE NEW BRITISH 
PHARMACOPEIA.* * 
BY C. H. WOOD. 
(The New Notation alone is used.) 
(Continued from page 20.) 
Acidum Hydrochloeicum. —The strength of this acid has been reduced. 
It is now ordered to be of sp. gr. 1T6. This corresponds to the ordinary 
pure hydrochloric acid of commerce. It contains 3T8 per cent, by weight of 
real H C1. The acid of the previous Pharmacopoeia had a density of 1T7, 
and contained 34 37 per cent, of HC1; but manufacturers are not accustomed 
to produce an acid of this strength, and no advantage was gained by its use. 
Neither of these acids contain the acid and water in simple atomic propor¬ 
tions, but they both approximate to a mixture of IIC1+4H 2 0, which contains 
33*6 per cent, of HC1, and has a density, according to Ure, of 1*167. In the 
last London Pharmacopoeia the saturating power assigned to hydrochloric 
acid, sp. gr. 1*16, indicated 33*9 per cent, of HC1, which would make it cor¬ 
respond exactly to HC1+4H 2 0, but the strength of the acid was undoubtedly 
over-estimated in that work. 
Beyond a readjustment of proportions, and some verbal amendments, the 
process is unchanged. One atom of chloride of sodium is mixed with 
one of sulphuric acid, previously diluted with about two-thirds its bulk of 
water. Heat is applied to the mixture, and the liberated gas is conducted 
into cold water, by which it is absorbed. 
NaCl + H 2 S0 4 =HCl-fNaIIS0 4 . 
The principal impurities of hydrochloric acid are sulphuric and sulphurous 
acids, chlorine, arsenic, and iron. The test now given for sulphurous acid is 
identical with that already described under acetic acid, namely, reducing 
the sulphurous acid to sulphuretted hydrogen by nascent hydrogen. 114*8 
grains’ weight of hydrochloric acid require for neutralization 1000 grain- 
measures of the volumetric solution of soda. As 1000 grain-measures of the 
volumetric solution contain one atom in grains of hydrate of soda, 114*8 
grains of the acid contain 36*5 grains, or one atom of HC1, which is in the 
proportion of 31*8 per cent. 
Acidum Hydrocyanicum Dilutum. —No material change has been made 
in the description of this acid. Ferrocvanide of potassium is distilled with 
* Page 19, line 14,./br 2C 6 II 6 0,2H0 read 2C 6 H 6 0,H 3 c/; line 1 6, for C 6 H a (N0 2 iU 3 read 
CeH^NO^O. 
* 
