30 SECTIONAL ADDRESSES. 
prove so fascinating as to distract his attention from the experimental 
basis of the science. 
When we look at the enormous mass of chemical research which is 
published each year, filling a greater and greater space on our book- 
shelves, we may ask ourselves whether any progress comparable with that 
which I have been describing is perceptible. It will probably be admitted 
that the work is proceeding, for the most part, along well-worn paths, 
although sometimes with most striking results. The work on the structure 
of carbohydrates under Irvine on the organic side, and that of McBain 
and his collaborators on soaps in physical chemistry, may be mentioned 
as examples of the highest class of productive investigation now in pro- 
gress. On the theoretical side, chemistry would seem to have been marking 
time, contenting itself with waiting for discoveries in physics, which might 
then be applied. Quite recently, however, we have seen new explanations 
of the reactions of organic compounds, based on the ideas of polarity and 
of residual affinity. As we are to have a full discussion of this subject 
before the close of the meeting, in which we shall have the advantage of 
hearing the originators of the several hypotheses intended to co-ordinate 
the facts of organic reactivity describe their reasoning in their own language, 
T need not do more than welcome this new sign of activity in chemical 
thought. The doctrines have still to be submitted to the supreme test. 
The main service of the older hypotheses of atoms, of structure, &c., 
to which I have referred was not the co-ordination of existing knowledge, 
valuable as that was, but the prediction of new facts. All of them have 
passed that test triumphantly. New facts have been predicted, and the 
concordance of observation with prediction has been extraordinary. 
Confidence in an hypothesis grows with every successful prediction, until 
the mass of evidence in its favour proves overwhelming. Will history 
repeat itself in this respect ? It is to be hoped that it will do so. The 
interpretation of the reactions of the elements by means of the Bohr 
electronic groupings has been greatly assisted by the fact that those re- 
actions were already known, and it has been possible to develop the hypo- 
thesis by successive adaptations as more facts were considered, but the 
supreme test, that of predicting some entirely new range of phenomena, 
has still to be applied, and chemists will look eagerly for its success in due 
course. The same thing may be said of the theories of organic reactivity. 
Are they capable of opening up a new field of phenomena which would 
otherwise have remained unknown ? To this question also we shall await 
an answer. 
An unfortunate consequence of excessive and premature specialisation 
in the study of chemistry is the ignorance of many advanced students 
concerning the work of the great chemists of the past. When attention is 
mainly concentrated on the latest developments of some restricted branch 
of the science, the sense of historical perspective is lost, and too much 
weight is given to what may be only a perfection of detail. Faraday and 
his contemporaries are far too little known to our young graduates in 
chemistry. Some teachers of the subject adopt the admirable plan of 
giving an historical and biographical colouring to their teaching, so en- 
suring that their students understand something of the debt which the 
science of to-day owes to its great leaders of the past. The interest now 
being taken in the history of science generally, and the appearance of 
