16 
REMARKS ON THE ACIDS OP THE BRITISH FHARMACOPCEIA. 
76. Chloruee de Potassium. KC1 = 746. 
Chloruretum Potassicum. 
Chloride of Potassium. Potassic Chloride. 
This is prepared by saturating an aqueous solution of carbonate of potash 
with hydrochloric acid, evaporating and crystallizing. For the preparation of 
chlorate of potash, which is so largely prescribed in England, no form is given 
in the Codex. 
CHAPTER VI. 
BROMIDES. 
It is scarcely correct in the Codex to call this a chapter of bromides, seeing 
that it contains but one. 
77. Beomure de Potassium*. KBr= 119*1. 
Promuretum Potassicum. 
Promide of Potassium, or Potassic Promide, 
is to be prepared by mixing bromine with a solution of caustic potash and evapo¬ 
rating to dryness; the residue of the evaporation to be put into a platinum cru¬ 
cible, and, when fused, to be so maintained for some minutes at a dull red heat, 
so as to convert the bromate into biomide : the saline mass is to be redissolved 
in distilled water, evaporated and crystallized. Th*e rationale of the P. B. pro¬ 
cess is the same, only instead of the platinum crucible, which may be very well 
in a small way, the dry residue, intimately mixed with wood-charcoal, is thrown 
into a red-hot iron crucible, fused, poured out, and, when cold, dissolved in dis¬ 
tilled water, and the solution filtered and crystallized. 
(To be continued.) 
REMARKS ON THE ACIDS OF THE NEW BRITISH 
PHARMACOPOEIA. 
by c. H. WOOD. 
(The New Notation alone is used.) 
Acetum. —British vinegar is now substituted for French. It is only re¬ 
quired for the preparation of emplastrum cerati saponis, and for this purpose 
the English vinegar answers better, while it is more readily obtainable than 
the French. The English law permits the addition to vinegar of 
part by weight of sulphuric acid. To detect any excess of the latter ingredient 
the P. B. directs 10 minims of solution of chloride of barium to be added to 
* 1 ounce of the vinegar, and the liquid to be then filtered ; the filtrate should 
give no precipitate on a further addition of the test. For more precise purposes 
it may be stated that 1 ounce of vinegar should not give more than 1*06 
grains of BaS0 4 . 
Acidum Aceticum. —This acid is now defined as follows :— u An acid liquid 
prepared from wood by destructive distillation and subsequent purification. 
100 parts by weight contain 33 parts of the acetic acid H0,C 4 H 3 0 3 or 
HC 9 H 3 0 2 , corresponding to 28 parts of anhydrous acetic acid, C 4 H 3 0 3 or 
c 4 h 6 o 3 / 
It will be seen that chemical formulae are introduced into the text in order to 
give exact definition to the terms “ the acetic acid” and “ anhydrous acetic 
acid” respectively. Probably some chemical teachers of the present, day will 
however consider that both these terms properly belong to the same substance ; 
and that the body C 4 H 6 0 3 cannot be correctly named anhydrous acetic acid. 
According to the modern acceptation of the word an acid is a salt of hydrogen ; 
