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SHEFFIELD PHARMACEUTICAL AND CHEMICAL ASSOCIATION. 
On Wednesday evening, November 10th, the first lecture of the session was delivered 
before the Sheffield Pharmaceutical and Chemical Association bv Mr. H. C. Sokby, 
F.R S. J 
Ihe subject was “The Application of the Spectrum Microscope to the Detection of 
Adulterations.” The lecturer first gave a general account of the principles involved in 
this particular kind of spectrum analysis, which differ entirely from those in the case 
of incandescent vapours. 
\\ hen any substance used as an adulterative gives a spectrum with one or more well- 
marked absorption bands, it is often very easy to detect it when mixed with others. 
Thus, for example, some of the aniline colours or cochineal may be easily recognized 
when added to various syrups or tinctures to increase or improve the naturally defective 
tint. 
In many cases, however, it would not be possible to adopt such a simple method, and 
it is therefore requisite to more or less perfectly separate the suspected substance from 
the main mass of coloured solution. As an example of this, the lecturer described how, 
by means of ether, the colouring-matters of logwood or Brazil wood may be separated 
from dark-coloured wines adulterated with them. When agitated with pure wine, the 
ether rises to the surface in an almost colourless state, whereas, when it contains either 
of the above-named substances, it is of a more or less deep yellow colour; and, after 
having been evaporated to dryness, the addition of a small quantity of bicarbonate of 
ammonia to the aqueous solution developes spectra which can be easily recognized as 
those of either the logwood or Brazil wood. Bisulphide of carbon and benzole may also 
be employed in a similar manner, wdth great advantage, to separate other colouring- 
matters from a large amount of such complicated mixtures as often present them¬ 
selves for examination. By using the bisulphide we may easily separate the colour of 
red annatto from highly coloured cheese, and recognize it by the characteristic spectrum, 
or detect the colouring matter of carrots in butter. 
Benzole is a most useful reagent in separating turmeric from rhubarb or other sub¬ 
stances factitiously coloured by it, and the presence of an extremely minute quantity 
may be easily recognized by means of its powerful fluorescence when dissolved in that 
liquid. In conclusion the lecturer said that he had not in any way aimed at giving a 
complete account of the subject, for that would have been far too detailed and tedious 
for a general lecture, but had confined himself to a few of the more simple and striking 
cases, in order to illustrate the sort of methods which might be employed in such 
inquiries. 
Mr. Wilson proposed a vote of thanks for Mr. Sorby’s excellent lecture, which was 
seconded by Mr. Dobb and carried unanimously. Shortly after, the meeting broke up. 
SUNDERLAND CHEMISTS’ ASSOCIATION. 
The second meeting of the above Association was held on Monday evening, November 
8th, in the Athenaeum, under the presidency of Mr. Harrison Thompson, to hear an ad¬ 
dress from Mr. Nicholson on structural botany. The lecturer, who was throughout listened 
to with very marked attention, explained minutely the leading principles of the science, 
and illustrated his remarks by means of diagrams and specimens of roots, leaves, etc., 
with which he had provided himself. He concluded his very able lecture by pointing 
out the direction which students of this science should pursue, and promised, at a future 
time, to offer further remarks on the subject. At the close, votes of thanks were accorded 
to the lecturer and the chairman. The next lecture under the auspices of the society is 
fixed for December 6th. 
