March iSth, ipi^] PROCEEDINGS. xxiii 



This product when crystallised from alcohol or glacial acetic acid 

 yields the racemic pimaric acid showing a melting point of 1 58°C., 

 and having a specific gravity at i^'C. of i'o8. It is remarkable 

 tliat the racemic compound shows by cryoscopic methods (boil- 

 ing point in benzene and alcohol and freezing point in benzene) 

 a double molecular weight while the 1 modification behaves 

 normally. After numerous unsuccessful attempts to resolve tlie 

 racemic pimaric acid into its optical isomerides, it was found 

 that this could be effected by means of d-tetrahydroquinaldine. 

 'llie subject is being further investigated. 



Mr. R. F. GwYTHKR, M.A., read a paper, entitled 

 "The Specification of Stress. Part IV. The Elastic 

 Solution : the Elastic Stress relations and conditions 

 of Stability : Struts, ties, and test-pieces." 

 This paper is printed in full in the Memoirs. 



Special Meeting, March iSth, 1914. 



The President, Mr. Francis Nicholson, F.Z.S., 

 in the Chair. 



At the Society's invitation, Professor W. H. Bragg, 

 M.A., F.R.S., delivered a Special Lecture on "Crystalline 

 Structure as revealed by X-rays. 



Ordinary Meeting, March 24th, 1914. 



The President, i\Ir. Francis Nicholson, F.Z.S., 

 in the Chair. 



A vote of thanks was accorded the donors of the books 

 upon the table. .Amongst these were : "• Elenienls of Ihc History 



