534 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. [December 31,1870. 
SHEFFIELD PHARMACEUTICAL AND 
CHEMICAL ASSOCIATION. 
The Third General Monthly Meeting was held in the 
Rooms, Music Hall, on Wednesday, December 14tli; Mr. 
Wilson, the President, in the chair. A lecture upon 
“ The Laws of Heat ” was given by an honorary member 
of the Society, W. Baker, Esq., F.C.S. It was of a very 
interesting and suggestive nature, illustrated by experi¬ 
ments, and elicited much applause. The following is a 
short abstract:— 
Heat is only known, to us by its effects. We are 
familiar with the sensation of heat; we observe that it 
•causes a change of volume in matter, that it renders 
bodies luminous and so forth. Heat may be conveniently 
studied under two heads, absorbed heat and radiant heat. 
Sensible heat is measured by thermometers ; but it must 
be borne in mind that what we really observe is the ex¬ 
pansion of a liquid or gas in making use of such instru¬ 
ments, and the requirements for a good thermometer are 
not easily fulfilled. Allowance must be made for the 
expansion of the glass as well as the fluid it contains. 
The meaning of 21*2° Fahr. must not be lost sight of; it 
is really the temperature at which water boils under a 
barometric pressure of 29-90<5 at London. 
The dilatation of solids, liquids and gases was noticed, 
.and the superiority of air thermometers shown by the 
fact that the coefficient of expansion of all gases was 
practically the same; hence all air thermometers are 
comparable one with another. The applications of a 
knowledge of these laws of expansion were shown to be 
extremely numerous in the arts. The quantity of heat 
•was measured in various ways, and constituted a sepa¬ 
rate chapter on heat called calorimetry. The combus¬ 
tion of a weighed quantity of fuel under water by means 
of a mixture of potassic chlorate was shown to raise a 
certain bulk of water so many degrees, and thus furnish 
a 'practical measure of its calorific value,—the unit of 
heat being 1 lb. of water raised from 32° to 33° Fahr. 
The change of specific heat upon compression was noticed 
and illustrated. The general facts attending liquefaction 
and solidification, and the effects of heat, stored up as it 
were in a liquid, were shown to have important effects 
upon our climate. One ton of water upon freezing was 
.stated to give out sufficient heat to raise one ton of 
water from 32° to 174° Fahr. Development of heat upon 
solidification was illustrated by the sudden crystalliza¬ 
tion of a solution of sodic sulphate, which had been pre¬ 
viously cooled in a flask; upon removing the cork the 
contents became a mass of crystals in a few seconds, and 
the heat could be observed by an immersed thermometer. 
Hope’s experiment upon the changes of density of water 
near its freezing-point was mentioned. 
The phenomena of evaporation, ebullition and the 
.spheroidal condition of fluids were described. Conduc¬ 
tivity of heat in metal bars was illustrated by attaching 
light balls by means of wax to the bars and heating the 
ends. The superior conductivity of copper over iron was 
thus easily perceived. Finally, the general laws of ra¬ 
diant heat were enunciated, and the effect of concen¬ 
trating the radiant heat from a hot ball upon an air 
thermometer, shown to be very considerable at a distance 
.of many feet. 
At its conclusion a cordial vote of thanks to Mr. Baker 
was proposed by Mr. Wilson, seconded by Mr. Douu, 
and carried unanimously. In consequence of the late¬ 
ness of the hour no further business was done. 
BRISTOL PHARMACEUTICAL ASSOCIATION. 
On Friday, December 16th, the second monthly lec¬ 
ture of the current session in connection with the above 
Association was delivered by their Professor of Che- 
mistry, Thomas Coomber, Esq., F.C.S. The subject 
was “Heat,” and the following notes indicate the range 
and order of the phenomena treated of by the lecturer. 
Introductory .—A current of electricity controls the 
position of a proximate magnetic needle. Such a current 
is established by the addition or subtraction of heat from 
two different metals in contact. This arrangement used 
in conjunction with the magnetic needle becomes there¬ 
fore a thermoscopc. 
(1.) An experimental inquiry into the nature of heat. 
(2.) Observation of the effects of heat upon matter. 
(a.) Change of volume. Experiments to study this 
change on solid, liquid and gaseous bodies. Thermo¬ 
meters. The Trevelyan instrument. Observation of 
the exceptional deportment of water, (b.) Change of 
temperature. Experiment to illustrate the dissimilar 
capacities of different bodies for heat, (c.) Change of 
physical condition. Latent heat of vapours and liquids. 
Effects of congelation. 
(3.) Study of the modes by which heat may be trans¬ 
mitted. ( a .) By conduction. Experiments to show that 
dissimilar bodies conduct heat at different rates, and that 
liquids are sluggish conductors. ( b .) By convection. 
Experimental illustrations of this mode of transmitting 
heat, (c.) By radiation. It may be shown by experi¬ 
ment that heat travels in straight lines, that the angle 
of reflection is equal to the angle of incidence, and that 
dissimilar surfaces radiate at different rates. 
Ilramhitrijs jof SrimMc Sandies. 
SOCIETY OF ARTS.* 
On Fermentation. 
BY FROFESSOR A. W. WILLIAMSON, F.R.S. 
Lecture IV. 
We had occasion last week to notice the effect of the 
atmosphere on processes of fermentation in several in¬ 
stances. I mentioned, among other things bearing on 
that question, an experiment of Gay-Lussac, in which 
he squeezed some very ripe berries of the grape under 
mercury, and kept them, with due precautions for the 
exclusion, as far as he knew, of everything except the 
grape-juice; he kept this expressed juice for some time 
quiescent, and then introduced a bubble of air, or a 
bubble of oxygen, the active substance of air, but he 
subjected the air or the oxygen, before introducing it 
into this juice, to various strong influences, which must 
have destroyed any vital organism in it; and he found 
that the mere addition of the air to the quiescent juice 
caused a process of fermentation to commence and a 
formation of organisms to begin, that they developed 
themselves, and that the liquid fermented in the usual 
way. The fact of the fermentation commencing is, if 
we bear in mind the general results of M. Pasteur’s re¬ 
searches, to be attributed to the presence in the mercury 
or in the grape-juice, or somewhere or other in the sub¬ 
stances present, of bodies which, by the mere access of 
oxygen, were stimulated so as to developo themselves 
into these little vital cells. It is now known, I may say, 
that there are in mercury, unless it is purified with ex¬ 
traordinary precautions, always present some such or¬ 
ganisms, capable of developing themselves under such 
influences ; and it is probable, I will not say more than 
that, for I do not know, that in the grape-juice there 
may also be similar germs present. The functions of 
oxygen appear from that experiment—which has since 
been confirmed by other observers—to be essential, at 
all events, to the initiation of the process, and there is 
in that respect, a remarkable analogy, which I think is 
interesting to recall to mind, with the action of oxygen 
* Cantor Lectures. 
