SECTIONAL TRANSACTIONS.— B, C. 321 



the second is of the most interest in connection with the polythionic acids. 

 Trithionic acid is the primary thionic acid both in the Wackenroder reaction and 

 in the decomposition of thiosulphates by acid. The higher thionic acids are formed 

 from trithionic acid by addition of sulphur, the chief sulphurising agent being 

 thiosulphuric acid. 



Prof. H. Bassett. — The Cobalt Chloride Colour Change. 



In 1902 Donnan and Bassett (Trans. Chem. Soc. 81, 939) showed that red cobalt 

 chloride solutions contained a red cation while blue solutions contained a blue anion. 

 A phase rule study of the systems CoCl^-HCl-H,©, CoCIj-MgClj-HoO. 

 CoClo — HgCL— HoO and C0CI2— ZnCL — H.^O has now been made to try and determine 

 the precise nature of the red and blue ions present in the several solutions. 



From the nature of the crystalline compounds which have been isolated it is 

 concluded that in cobalt chloride solutions there may exist, according to the prevailing 

 conditions, the red cations [Co(H,0)8]--, [Co(H.,0)4]" and possibly [CoC^HjOJa]- and 

 the blue anions [CoCl4(H„0),]", [Coaj" and [CoClj(H.,0)]'. 



The results obtained lend no support to the views of Hill and Howell (Phil. Mag. 

 1924, 48, 833) that cobalt co-ordinated with six groups is red and with four groups 

 blue. It is the electrical condition which is of most importance, not the co-ordination. 



Prof. E. C. Franklin. — The Ammonia System of Compounds. 



Observing that ammonia resembles water in all its physical and chemical properties, 

 and looking upon the familiar oxygen bases, acids and salts, the alcohols, ethers, 

 aldehydes, ketones, &c., as derivatives of water and thereby constituting a water 

 system of compounds, then it is reasonable to assume the existence of compounds 

 analogously derived from ammonia. As a matter of fact, such an assumption has 

 been experimentally justified. Using liquid ammonia as solvent in which to carry 

 out the necessarj' reactions, it has been shown that the metallic amides and imides 

 possess all the characteristic properties of bases, that the non-metallic amides and 

 imides are acids the metallic derivatives of which are salts. Most organic compounds 

 containing nitrogen may be interpreted as alcohols, ethers, aldehydes, acids, ketones, 

 acetals, aldols, or as mixed compounds showing simultaneously the properties of two or 

 more of these classes of compounds. 



SECTION C— GEOLOGY. 



(For reference to the publication elsewhere of communications entered in the 

 following list of transactions, see p. 428.) 



CAPE TOWN. 

 Tuesday, July 23. 



Prof. A. Young. — The Geology of the Neighbourhood of Cape Town. 



Dr. F. DiXEY. — The Geology of the Lower Shire-Zambezi Area. 



The Lower Shire-Zambezi area forms a relatively small salient between the better- 

 known parts of Portuguese East Africa lying to the north and the south, and a study 

 of its geology in relation to that of the larger territory has yielded interesting results. 



1929 Y 



