-Jane 29, 1872.] 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
1061 
these are only artifices to express certain transformations, 
and that we are really ignorant of the relative position 
of the atoms either in space or in the mutual action of 
different portions of matter. With these reservations, 
it is possible, in teaching to derive considerable advan¬ 
tage from the theory of atomicity, and at the same time 
to avoid its inconveniences. 
In the study of the transformations which matter 
undergoes, we should direct the pupil’s attention, not 
only to the ponderable changes in the composition 
of molecules, but also to the electrical and calorific 
phenomena which accompany these transformations. 
Even from Lavoisier’s time it has been recognized that 
we cannot separate the study of matter from thermic 
considerations; and every day the connection which 
exists between chemical and thermic phenomena becomes 
more apparent. 
As in the study of ponderable changes we were guided 
hy the law of the conservation of weight, so in the con¬ 
nection between chemical and dynamical phenomena we 
are guided by the law of the conservation of force ; the 
two studies mutually supplementing and illustrating one 
another. Not only will the atomic and molecular 
theory and that of atomicity help us to compare dynami¬ 
cal phenomena, but the study of dynamical phenomena 
will show us analogies and differences between chemical 
actions which would not be observed in the ponderable 
equations. We should therefore instruct the student in 
the little definite knowledge which we at present possess 
concerning thermic and electric phenomena, and especi¬ 
ally fix in his mind the fundamental notion of a mechani¬ 
cal equivalent, and the manner of comparing it with 
chemical action as expressed by the atomic theory. In 
this we should be aided by the previous or simultaneous 
instruction of the student in physics under the form and 
language of the thermodynamic theory. 
The lecturer concluded by observing that in the choice 
of methods and of matter for a course of chemistry, it 
should always be borne in mind that it was eminently a 
progressive science, and that even at the time of its most 
rapid development. The student should start not only 
with a knowledge of certain definite and fixed principles, 
but with an apitude and sufficient preparation to enable 
him to follow the science in its unceasing transformation 
and progress, whether he intends expressly to cultivate 
chemistry, or has only learnt the elements of the science 
as an auxiliary to other studies or professions. More¬ 
over, the end of chemical instruction for both these classes 
of students is not only to fix in their memory a certain 
amount of knowledge, but to assist in their intellectual 
education. For this, chemistry of all sciences is one of 
the best, offering both in verbal and practical instruc¬ 
tion—excellent occasions for the exercise and harmonious 
development of all the faculties of the human mind. 
He had desired to call attention to what he considered 
to be the most efficient means of imparting a knowledge 
•of chemistry so that it might serve as an instrument of 
intellectual education, and that the student, by following 
it in its ulterior developments, might judiciously apply 
it to the study of the other branches of natural science. 
If the attention of the eminent chemists and professors 
there present were once attracted to this subject, he felt 
-certain that a bright light would be thrown on it, and 
that our young professors would find numerous sugges¬ 
tions to direct them in teaching chemistry, and that at 
the very moment when instruction in our science had j 
become so difficult on account of the rapid transformation 
which it was undergoing. 
Dr. Williamson said, that those who were there pre¬ 
sent ought not to separate without some expression of 
the pleasure that they had felt on listening to so learned, 
vast, and eloquent a discourse, treating as it did of a 
most difficult and important problem. There was 
.scarcely anything of greater moment in the scientific i 
education of youth than the rightly setting before them ! 
those wonderful transformations of matter which it is 
the province of chemistry to explain. These great and 
growing truths, for, as the lecturer had said, they were 
growing truths, should be set before youth in such a 
manner as to form a coherent whole. He hoped to 
study this masterly discourse with profit and delight, 
and would now propose a vote of thanks to his illus¬ 
trious colleague for the honour which he had done them 
in delivering to them the Faraday lecture. 
Professor Tyndall said he had heard the discourse 
with deep interest, for it showed that the lecturer knew 
the importance of a teacher’s vocation, and that his pro¬ 
vince was not merely to communicate knowledge, but to 
do it in such a manner as to arouse an interest in and 
love of the subject in the pupil by presenting it in its 
proper relations. He would have welcomed the lec¬ 
turer to that Institution, even had he come to tear in 
pieces the notions which he cherished regarding atoms 
and molecules; how pleasant it was then to find such a 
broad agreement between their views. The chemist 
cannot halt at equivalent proportions—he must ask him¬ 
self whence they arise, and the inevitable answer is 
some form of the atomic theory. This theory, however, 
cannot be confined to chemical phenomena. The mo¬ 
tions of those atoms and molecules underlie all our ex¬ 
planations of the physical cause of light and heat, and it 
is already taking up the field of magnetism and electri¬ 
city. Consider, for example, the heat of gases, both as 
regards the motion of translation of the molecules 
which produce temperature, and the motions of rotation 
and vibration of their constituent atoms, which, though 
they do not express themselves as temperature, consti¬ 
tute a portion of the heat. Clausius has shown that 
even in the simplest gases nearly two-fifths of the whole 
heat is due to these internal motions ; while in gases of 
complex molecular constitution which condense on com¬ 
bining, the ratio of the total heat to the heat of tempe¬ 
rature is still greater. The experiments of Regnault, 
which show that the specific heat of a perfect gas at a 
constant volume is constant, proves, as Clausius has 
shown, that the one kind of motion is proportional to 
the others. 
The lecturer had also referred to atoms of the same 
kind combining together, so that, free oxygen and free 
hydrogen being considered as composed of molecules, 
each containing a pair of atoms, has certainly simplified 
the results. But it must not be forgotten that this 
combination of like atoms is widely different from that 
of unlike atoms. The union of oxygen with oxygen or 
nitrogen with nitrogen produces no such effects upon 
the luminiferous ether as the union of oxygen with 
nitrogen. With the same quantity of matter the 
amount of vis viva sent forth as radiant heat may be 
augmented a thousandfold, perhaps a millionfold, by the 
act of diverse combination. This act seems to carry 
with it a condensation of the ether to a dense atmo¬ 
sphere around the atoms. Had a cannon the power of 
gathering round itself a dense atmosphere, it would 
send forth a greater amount of vis viva as sound. A 
gun fired at Chamouni may be heard upon Mont Blanc, 
while the same gun fired on Mont Blanc may not be 
heard at Chamouni, because the air on which the con¬ 
cussion takes place is denser in the one case than in the 
other. In the same way the diverse atoms vibrating in 
the denser atmosphere formed on combination show 
their vast superiority as radiators over like atoms which, 
except in such special cases as ozone, etc., are incompe¬ 
tent to produce a similar condensation. The speaker 
then asked them to echo the resolution so well put to 
the meeting by Prof. Williamson. 
Thursday, 20th June, 1872 ; Dr. Frankland, F.R.S., 
President, in the chair. 
After the usual business of the society had been trans¬ 
acted, the President announced that Mr. Hyde Hills 
had given ten guineas to the fund for promoting original 
