SHEFFIELD ASSOCIATION OF CHEMISTS AND DRUGGISTS. 331 
try ; this he did by showing that the different gases diffuse with a rapidity inversely as 
the square root of their density, or specific gravity. The fire-damp in coal-mines was a 
gas escaping from coal, and was a compound of carbon with hydrogen, which caused 
such disastrous explosions when allowed to come in contact with the flame of a candle. 
This was illustrated by experiments, which forcibly portrayed the high diffusibility of 
fire-damp, and he showed how its presence might be made apparent by an application of 
the process of diffusion invented by Mr. Anseli. Dialysis was a term used to express 
the diffusion of liquids through membranes, and in order to convey the meaning and 
use of this process more fully, he showed some experiments, distinguishing the crystal¬ 
loids, colloids, and uucrystallizable substances. He said silica and glass had been 
known to be dissolved by water under high pressure; the experiment had been success¬ 
fully carried out by our eminent townsman, C. Sorby, Esq., F.R.S., showing that glass 
may be dissolved in water, and the silica obtained therefrom by the diffusion process ; 
and he further illustrated how alkaloid crystals may be obtained by this process. 
After a very interesting discussion upon the subject, a vote of thanks was unanimously 
recorded to the lecturer for so instructive a paper. 
The Annual Dinner was held at the King’s Head Hotel, on Thursday, Dec. 19th ; Mr. 
Ward, the President, occupied the chair, and Mr. Hornby, the President of the United 
Society of Chemists and Druggists of the United Kingdom, officiated as vice-chairman. 
After the usual loyal and patriotic toasts, Mr. Brown proposed the toast of the evening, 
that of “ Success to the Sheffield Association of Chemists and Druggists.” In doing so, he 
congratulated the members on the progress which the Society had made since its first 
meeting, and he noticed with pleasure the improvements which were to be observed in 
their trade in the town of Sheffield. He expressed a hope that in future the Association 
would continue its useful career, and that the number of its members would increase. 
Mr. Hornby was called upon to respond. It was, he said, very pleasing to note the pro¬ 
gress of the Association, which might be attributed in a great measure to the lectures 
and papers rendered at the monthly gatherings, affording, as they did, instruction not 
only to the members, but to the assistants and apprentices. The latter were encouraged 
by the offering of prizes for competition; and it was remarkable how speedily the diffu¬ 
sion of practical chemistry incited them to study. In these days of scientific knowledge, 
unless men were well up in details they seldom rose past mediocrity ; and the public at 
large were, he believed, beginning to acknowledge those who, by perseverance in the 
paths of knowledge, rendered themselves better qualified to discharge the trust confided 
in them. For years it had been the endeavour to raise the standard of chemical know¬ 
ledge amongst chemists and druggists, and various means had been adopted to obtain so 
desirable a result; but, until the formation of this Society, all attempts had failed. 
The encouragement which it had received, however, in the town of Sheffield among the 
fraternity augured well for the future standing of the profession. Nor was it in Sheffield 
alone that these benefits had been promulgated, but throughout England the spirit of 
inquiry and the thirst for knowledge had made the United Society one of the most stable 
and promising institutions of the day, and should the Pharmaceutical Society continue 
to hold out the hand of friendship and sympathy to those not as yet connected with 
them except in name, they might rest assured that the general good would far out¬ 
weigh the isolation which their society had held for many years. No doubt there were 
many calling themselves members of the Pharmaceutical Society who desired to retain 
the privileges to themselves, although, practically, in chemical knowledge they were far 
behind hundreds of their fellow-tradesmen ; but thanks to the liberal spirit of the Phar¬ 
maceutical Council, there was now hope for the realization of the general advancement 
of the trade in spite of the obstructionists. Therefore, it might be concluded that those 
associations alone had tended to stir up the apathy of the trade to those pursuits wffiich 
would be to them a source of pleasure and profit. He had great pleasure in responding 
to the toast. 
“ The Town and Trade of Sheffield,” “ Success to the United Society of Chemists and 
Druggists,” and otherToasts were proposed and duly responded to, and the evening was 
spent in a very agreeable manner. 
