4.22 REPORT—1904. 
sound mathematical perception, is written with great simplicity and an entire 
absence of pedantry or dogmatism. It ranks, I believe, with the best that has 
been done in the subject. It is to be regretted that, as an historian, he leaves so few 
successors among British mathematicians. We have amongst us, asa result of 
our system of university education, many men of trained mathematical faculty 
and of a scholarly turn of mind, with much of the necessary linguistic equipment, 
who feel, however, no special vocation for the details of recent mathematical 
research. Might not some of this ability be turned to a field, by no means 
exhausted, ‘where the severity of mathematical truth is tempered by the human 
interest attaching to the lives, the vicissitudes, and even the passions and the 
strife of its devotees, who through many errors and perplexities have contrived to 
keep alive and trim the sacred flame, and to hand it on burning ever clearer and 
brighter ? 
a another province we have to record the loss of Dr. Isaac Roberts, a dis- 
tinguished example of the class of non-professional investigators who have left so 
deep a mark on British science, and on Astronomy in particular. None of us can 
be unaware of his long and enthusiastic devotion to celestial photography, of the 
beauty and delicacy of the results which he achieved, and of the wealth of 
unsuspected detail which they brought to light. 
Finally, we have to lament the death, within the last few days, of Professor 
Everett, whose name will always be associated with one of the most successful 
tasks which the British Association has taken in hand—viz. the promotion of a 
uniform system of dynamical and electrical units. He acted as Reporter to the 
Committee which was entrusted with this question, and by his handbook on 
‘Units and Physical Constants’ he has done more perhaps than anyone else to 
popularise and establish its recommendations. He was well known to most of us 
as a bright and genial presence at these meetings, and contributed numerous 
interesting papers on optical and other subjects. Ie was happy in retaining his 
scientific faculties undimmed to the last, and was engaged up to the time of his 
death on some problems of a geometrical kind, on point-assemblages, suggested by 
the study of the recent speculations of Professor Osborne Reynolds. 
Of the various subjects which fall within the scope of this Section there is 
no difficulty in naming that which at the present time excites the widest interest. 
The phenomena of Radioactivity, Ionisation of Gases, and so on, are not only 
startling and sensational in themselves, they have suggested most wonderful and 
far-reaching speculations, and, whatever be the future of these particular theories, 
they are bound in any case deeply to influence our views on fundamental 
points of chemistry and physics. No reference to this subject would be satis- 
factory without a word of homage to the unsurpassed patience and skill in the 
devising of new experimental methods to meet new and subtle conditions which 
it has evoked. It will be felt as a matter of legitimate pride by many present 
that the University of Cambridge has been so conspicuously associated with this 
work. It would therefore have been natural and appropriate that this Chair should 
have been occupied, this year above others, by one who could have given us a 
survey of the facts as they at present stand, and of their bearing, so far as can be 
discerned, on other and older branches of physics. Whether from the experimental 
or from the more theoretical and philosophical standpoint, there would have been 
no difficulty in finding an exponent of unrivalled authority. But it has been 
otherwise ordered, and you and I must make the best of it. If the subject cannot 
be further dealt with for the moment, we have the satisfaction of knowing that it 
will in due course engage the attention of the Section, and that we may look 
forward to interesting and stimulating discussions, in which we trust the many 
distinguished foreign physicists who honour us by their presence will take an 
active part. 
It is, I believe, not an unknown thing for your President to look up the 
records of previous meetings in search of inspiration, and possibly of an example. 
I have myself not had to look very far, for I found that when the British 
Association last met in Cambridge, in the year 1862, this Section was presided 
over by Stokes, and moreover that the Address which he gave was probably the 
