SECTIONAL TRANSACTIONS.— At, B. 317 



A similar investigation shows that at Oxford (RadclifFe Observatory) 

 corresponding changes of temperature have occurred. Oxford, however, 

 has experienced an increase of rainfall amounting to 22 per cent, in spring 

 and 14 per cent, in winter, though winter sunshine has increased by 12 per 

 cent. 



Mr. M. G. Bennett. — The effect of the spectral transmission of the atmosphere 

 upon visibility by artificial light. 



(i) Summary of experimental work bearing on the transmission by the 

 atmosphere of light of different wave-lengths. 



(2) Application of the results of this work to the problems of — 

 {a) the visual range of point sources of light ; 



{b) the visual range of objects illuminated by the beam of a search- 

 light or motor-car headlight ; 

 with conclusions as to the effect of the colour of the light on the visual range 

 in the two cases. 



Mr. W. M. H. Greaves. — The new transit circle under construction for the 

 Royal Observatory , Greenwich. 



Television Demonstrations. 

 The Marconi Company kindly gave demonstrations of television by 

 radio from Chelmsford to the meeting-room of Section A (Mathematical 

 and Physical Sciences). 



SECTION B.— CHEMISTRY. 



Thursday, September 1. 



Presidential Address by Dr. W. H. Mills, F.R.S., on Some aspects of 

 Stereochemistry. (See p. 37.) 



Discussion on Stereochemistry (Prof. Dr. J. Meisenheimer ; Mr. T. W. J. 

 Taylor and Mr. L. E. Sutton ; Dr. N. V. Sidgwick, F.R.S. ; 

 Dr. F. G. Mann ; Dr. S. Sugden ; Mr. J. D. Bernal) :— 



Prof. Dr. J. Meisenheimer. — The stereochemistry of oximes, hydroxyl- 

 amines and amine-oxides. 



An attempt is made to explain the inconsistency that compounds in which 

 nitrogen is 2-co-ordinate should show stereoisomerism, whilst unsymmetri- 

 cally substituted tertiary amines have not been found resolvable, although 

 in both types a pyramidal arrangement of the valencies niust be assumed. 



The possibility that the relatively great stability of stereoisomeric oximes 

 is connected with the presence of the hydroxyl-group is excluded by the 

 failure to resolve the substituted hydroxylamines EtNMeOH, HO3SC6H4, 

 NMe.OBz. 



The circumstances under which the co-ordination number 3 is associated 

 with a pyramidal configuration and the causes that determine the stability 

 of a pyramidal arrangement are discussed. 



Stress is laid on the fact that although quinoline oxide shows the greatest 

 similarity to the sulphoxides in the arrangement of electrons round the 

 central atom, it has proved non-resolvable. 



