Annual Report of the Council. 215 



at a distance and looks to stresses in the medium as the cause 

 of electric and magnetic action. The great work of Hertz 

 consists in the experimental proof which he has given of the 

 fact that electrodynamic action is transmitted through space 

 with a finite velocity. The investigation was one which 

 presented such great difficulties that nobody who did not 

 possess the highest theoretical knowledge, together with a 

 quite exceptionally great experimental ability, could under- 

 take it with any hope of success. In the course of his 

 researches he was led to an important discovery proving an 

 effect of light in facilitating the discharge of electricity 

 from solid surfaces. The paper in which he describes the 

 results of this and other investigations are models of clear 

 writing and lucid explanation. His most important work 

 was done at Carlsruhe, where he occupied the chair of Physics 

 from Easter, 1883, until January, 1889. In October of that 

 year he succeeded Clausius as professor at the University 

 of Bonn. A great part of the last three years of his life 

 was taken up with the preparation of a book on the principles 

 of Mechanics which has recently been published. It is a 

 work which deals with the logical and philosophical aspect 

 of the subject, and which will play an important part in the 

 history of the development of scientific ideas. Hertz died 

 on the 1st of January, 1894. It has been given to few men 

 to accomplish even during a long life as much as Hertz did 

 in the few years allotted to him for scientific work. He 

 was elected an honorary member of the Society in 1889. 



A. S. 



ARCHIBALD SANDEMAN was born near Perth, and took 

 his degree at Cambridge, where he was bracketed third 

 wrangler, in 1846. For a short time after obtaining his 

 fellowship at Queen's College, he held the office of Mathe- 

 matical Lecturer in that College. On the opening of Owens 

 College in 185 1, he was appointed the first Professor of 



