218 
BRITISH PHARMACEUTICAL CONFERENCE. 
to try its effects on the salts of ammonia. On adding a few drops of this solu¬ 
tion to pure spirit of wine, there was no immediate change beyond a very faint 
opalescence, but on boiling it there was an abundant dirty yellowish-wliite pre¬ 
cipitate thrown down. On adding a few drops of the same solution to about an 
equal amount of methylated spirit, there was neither an immediate change nor 
the slightest alteration after boiling,—the spirit remaining perfectly clear. Here 
then in this solution was at last found a chemical test which, although negatively, 
nevertheless, I think, infallibly proves the presence of methylated spirit. I 
have made many trials of it, both with different samples of spirit of wine and 
methylated spirit, and always with the same results. The test solution I use is 
made according to the following form :— 
Biniodide of Mercury . . 15 grains. 
Iodide of Potassium ... 25 grains. 
Water.1 oz. 
Solution of Potash . . . 1 oz. (Pharmacopceiastrength.) 
Dissolve the biniodide of mercury and iodide of potassium in the water, and when 
dissolved add the solution of potash. 
In using this test I generally put about half a drachm of the suspected spirit 
in a test tube and add about eight or nine drops of the test to it and then boil; 
no change indicates methylated spirit, whilst an abundant precipitate proves the 
presence of pure spirit. I have not been able to try the test on u cleaned spirit,” 
not knowing where to obtain it, but I have no doubt of its action being the same 
on that as on the “ uncleaned ” methylated spirit; I have, however, tried its 
effects on both methylated and pure spirit diluted with an equal bulk of water, 
and with the same results as when .they are in a strong state. In testing spirits, 
such as tinctures, mixed with or holding in solution organic matters, it will 
perhaps be best to distil over a few drops of it, although I do not think this will 
be absolutely necessary in all cases. I have not yet ascertained whether the vo¬ 
latile matters which might accompany the spirit in such a distillation interfere with 
the action of the test. On this application of the test I hope to read a paper at 
a future meeting. 
I have tried the test solution without the potash, but it has no effect on me¬ 
thylated spirit or pure spirit, either before or after boiling, but on adding 
the alkali and then boiling, the results are the same as when they are both 
added together. 
In conclusion, I think it right to state that I have not yet ascertained with 
sufficient accuracy to publish it, the cause of the precipitate in the spirit of wine 
on adding the test solution. The component of naphtha which prevents the 
formation of the precipitate in methylated spirit is acetone. 
Wilton , near Salisbury, Auyust 30, 1864. 
REPORT ON THE WEIGHTS AND MEASURES USED IN 
PHARMACY. 
BY MR. BARNARD S. PROCTOR. 
(Read at the Bath Meeting of the British Bharmaeeulical Conference , Sept. 1864.) 
At the Pharmaceutical Conference held at Newcastle last year, I read a paper 
on weights and measures, the object of which was to show, roughly, the nature 
of the changes which have gradually taken place in metrology, to infer from the 
past the nature of future changes, and the goal to which all changes must tend; 
to compare various systems, either at present in use or proposed for adoption, 
and show wherein lay their faults or their advantages, and thus to conclude 
which would, with the least inconvenience, lead us forward in the direction in 
which we must inevitably move. 
