4 Anniversary Address by Prof. C. S. Sherrington. 



Edmund James Mills held the Young Chair of Technical Chemistry in 

 the Glasgow and West of Scotland Technical College. His papers were 

 numerous both on applied and theoretical chemistry, and not a few of them 

 were contributed to this Society, the first of them now more than fifty years 

 ago. Eeturning to London in later life, he was for many years a frequent 

 attendant at the Society's meetings. 



Colonel John Herschel, a son of Sir John Herschel, and at one time 

 Deputy-Superintendent of the Great Trigonometrical Survey of India, had 

 been a Fellow of the Society for fifty years. He was a spectroscopic 

 observer of a solar eclipse as far back as 1868. 



Gabriel Lippmann, the eminent French physicist, died while at sea on 

 his way from Canada home to Paris. He had been a Foreign Member of 

 the Society for five, and twenty years. His interest in physics lay largely 

 in the philosophic aspect, though his name is most familiar in connection 

 with the capillary electrometer and with colour photography. Lippmann's 

 capillary electrometer became, so to say, a household tool in every physical 

 laboratory, and likewise in many biological laboratories. In animal physi- 

 ology it proved of unique service for the observations of the slight and 

 fleeting electromotive reactions of isolated nerve and muscle. Until the 

 advent of the string galvanometer it was the only instrument which could 

 really cope with them. 



Of Lippmann's process for the reproduction of colour by photography, 

 our Foreign Secretary, Sir Arthur Schuster, who knew him from a time 

 when they were fellow students together, kindly writes me as follows: — 

 " Lippmann's work on colour photography well illustrates his great experi- 

 mental skill. Independently of the late Lord Kayleigh, who, in 1887, had 

 on theoretical grounds foreseen the possibility of the reproduction of natural 

 colours by an interference method, Lippmann conceived the same idea ; but 

 the experimental difficulties were formidable. The method depends on 

 establishing a periodic structure in a photographic film by the interference 

 of the direct light and its reflexion from a metallic surface. It was neces- 

 sary for the purpose that the films unlike those in ordinary use, should 

 be transparent. The production of such films appeared for many years to 

 be an insoluble problem, but ultimately the difficulty was overcome, and 

 in 1901 Lippmann obtained his first success ; but it was several years 

 before he could secure the equality of sensitiveness throughout the visible 

 spectrum which is essential if the natural colours are to appear with 

 their correct values. The photographs obtained by Lippmann cannot be 

 reproduced in print, but may be shown with brilliant effect by projection 

 on a screen." 



