THE PRESIDENTIAL ADDRESS 17 



has been that these are discovered by methods not essentially 

 different from direct scrutiny. It is hoped that the present survey 

 may remind you that if we allow for a reasonable broadening of the 

 original meaning of the words, it remains true after all that ' seeing 

 is believing.' 



II. 



Science and Warfare. 



During the Great War itself, few scientific men in any country 

 doubted that it was their duty to do what they could to apply their 

 specialised knowledge to the purposes of war ; nor was it often 

 suggested by publicists that there was any countervailing considera- 

 tion : on the contrary they urged strongly that our resources in 

 this direction should be efficiently mobilised. It is chiefly in vague 

 general discussions that the opposite view becomes vocal. 



Science, it is urged, is the source of all the trouble : and we may 

 look to scientific men for some constructive contribution to finding 

 a remedy. It is worth while to inquire what basis there is for this 

 indictment, and whether, in fact, it is feasible for men of science to 

 desist from labours which may have a disastrous outcome, or at any 

 rate to help in guiding other men to use and not to abuse the fruits 

 of those labours. I may say at the outset that I have no sanguine 

 contribution to make. I believe that the whole idea that scientific 

 men are specially responsible is a delusion born of imperfect know- 

 ledge of the real course of the process of discovery. Indeed, very 

 much the same complaint was made before the scientific era. Let 

 me refer you to Shakespeare's play of Henry IV : — 



' Great pity, so it was 

 This villainous saltpetre should be digged 

 Out of the bowels of the harmless earth 

 Which many a good tall fellow had destroyed 

 So cowardly.' 



The quotation leads us to inquire how far the further development 

 of this particular kind of frightfulness into modern high explosives 

 was deliberate or not. 



In the course of systematic study of the chemistry of carbon 

 compounds it was inevitable that the action of nitric acid on sub- 

 stances like benzene, toluene, glycerine, cellulose and the like should 

 be tried. No one could foresee the result. In the case of benzene, 

 we have nitrobenzene, the key to the aniline dye industry. In the 

 case of glycerine, Sobrero obtained in 1846 the highly explosive 

 liquid called nitro-glycerine. He meant no harm, and in fact his dis- 

 covery lay dormant for many years, until Nobel turned his attention 



