April 2Si/i,ic)i4-'\ Procekdings. xxvii 



Ordinary Meeting, April 28th, 1914. 



'I'he President, Mr. Francis Nicholson, F.Z.S., 

 in the Chair. 



A vote of thanks was accorded to the donors of the books 

 upon the table. These included: '•'■ Ethnozoology of the Tewa 

 Ijidiafis" by J. Henderson and J. P. Harrington (Bulletin 56) 

 (8vo., Washington, 1914), presented by the Bureau of An:erican 

 Ethnology, Washington ; and " Geologic Atlas of the United 

 States," Folios Nos. 185, 187, 188, 189 and 190 (la. fol , 

 Washington, 191 2, 191 3), presented by the United States 

 Geological .Survey, Washington. 



Mr. C. L. Barnes, M.A., inaugurated a brief discussion 

 relating to Plane trees as a cause of certain pulmonary troubles. 



Mr. R. F. GwvTHER read a paper entitled "Specification 

 of Stress. Part V. An outline of the theory of 

 Hyper-elastic Stress." In this paper the author dealt 

 with the mathematical conditions of a body from the state of 

 exceeding the elastic limit and approaching that of rupture. 



Neither experiments nor experience in engineering practice 

 have supplied information which will aid in the mathematical 

 treatment of the interval between the failure of complete fulfil- 

 ment of Hooke's Law and the earliest stage of rupture. 



In this paper the author proposes to give a survey of the 

 mathematical conditions which obtain up to the stage when 

 rupture is imminent. 



I'he method is one which the autlior introduced in a paper 

 read before the Society in 1895. 



A paper on " The Photographic Action of n-rays," 



by Mr. H. P. Walmsley, M.Sc, and Walter Makower, B.A., 

 D.Sc, was read by the latter. Dr. Makower discussed the 

 photographic action of «-particles and showed micro-photographs 

 illustrating the path of the rays through a photographic film. 

 Each ((-particles in striking a grain of silver affects that grain in 



