xxvi Proceedings. ^January 2jrd, igi2. 



(8vo., New York, 1907), and a collection of some eighty 

 reprints, from various journals, of papers by H. F, Osborn, 

 presented by the author. 



Mr. T. Thorp, F.R.A.S., in presenting a crossed transparent 



grating to the Society, pointed out that the secondary spectra 



produced by the crossing of the gratings are quite pure and free 



from all " scatter." 



A hearty vote of thanks was given to Mr. Thorp for his 

 valuable present. 



Mr. J. R. GwYTHER, M.A., read a paper entitled, " On the 

 modes of rupture of an open hemispherical concrete 

 shell under axial pressure." 



The paper is printed in full in the Memoirs. 

 A note on the mechanical conditions involved in the above 

 question was read by Mr. R. F. Gwyther, M.A. 



General Meeting, February 6th, 191 2. 



The President, Professor F. E. Weiss, D.Sc, F.L.S., 

 in the Chair. 



Mr. H. G. FoRDER, B.A., Mathematical Master, Hulme 

 Grammar School, Oldham, was elected an ordinary member of 

 the Society. 



Ordinary Meeting, February 6th, 191 2. 



The President, Professor F. E. Weiss, D.Sc, F.L.S., 

 in the Chair. 



Mr. H. E. SCHMITZ, M.A., B.Sc, and Mr. G. P. Varlev, 

 M.Sc, were nominated auditors of the Society's accounts for the 

 session 1911-1912. 



