508 POPULAR SCIENCE MONTHLY. 



progress of science than the composition of a dozen monographs on iso- 

 lated points. For proof one need only point to the treatises of Salmon 

 himself, or recall (in another field) the debt which we owe to such 

 books as the ' Treatise on Natural Philosophy ' and the ' Theory of 

 Sound,' whose authors are happily with us. 



A modest but most valuable worker has passed away in the person 

 of Professor Allman. His treatise on the history of Greek geometry, 

 full of learning and 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 on the subject. It is 

 to be regretted that, as an historian, he leaves so few successors among 

 British mathematicians. We have amongst us, as a result of our sys- 

 tem of university education, many men of trained mathematical fac- 

 ulty and of a scholarly turn of mind, with much of the necessary lin- 

 guistic 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 mathe- 

 matical 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 ? 



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, ionization 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 chem- 

 istry and physics. No reference to this subject would, I think, be sat- 

 isfactory 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 there- 

 fore 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 philo- 

 sophical standpoint, there would have been no difficulty in finding ex- 

 ponents of unrivaled authority. But it has been otherwise ordered, 

 and you and I must make the best of it. If the subject can not be 

 further dealt with for the moment, we have the satisfaction of know- 



