SEC'i'IONAL TRANSACTIONS.— B. 



311 



form of a very fine powder. The material used in the earlier experiments was nickel 

 carbonate, which, however, required previous activation and was only effective for 

 about two hours. 



Considerable advantage is gained by the use of supported FeiO.t as catalyst, the 

 oxide, containing some Th02 as promoter, being deposited on kieselguhr which has 

 previously been coated with Al (OH).i. It has been found that the activity of the 

 powders is proportional to the magnitude of their electropositive charge in water 

 saturated with carbon dioxide. This fact has rendered possible determinations of 

 the rate of poisoning by the oxygen set free during the photosynthesis and the rate 

 of de-poisoning by carbonic acid. This has enabled the optimum intensity of the 

 light to be measured for the process to become continuous. 



The activity of the powders varies in a remarkable way with the amount of ThC^ 

 present in the Fe203, sharp maxima being observed when the Th02 content is about 

 1-31 and 212 per cent., with minima on either side of these amounts. The maximum 

 yield yet obtained of carbohydrates is 0-256 grm. with 100 grms. of powder in two 

 hours. 



Afternoon. 



Visit to The Bristol Potteries. 



Tuesday, September 9. 



Prof. M. W. Teavers, F.R.S.— iVew Experimental Methods for the Study 

 of Gas Reactions. 



Prof. C. S. Gibson and Prof. J. L. Simonsen. — Recent Investigations of 

 Organic Compounds of Gold. 



Diethyl gold bromide, originally investigated by Pope and Gibson (Journ. Chem. 

 Soc, 1907, 2061) readily forms co-ordination compounds. Of these, monoammino- 

 bromodiethylgold and monopyridinobromodiethylgold : 



NH, Et~ 



\ / 



Au 



/ \ 



Br Et 



Pyr Et 



\/ 



/ \ 



Br Et 



are colourless, stable, non-ionisable compounds produced from the unstable salts : 



Br 



first formed by the action of ammonia and pjrridine respectively on diethylgold 

 bromide. Efhylenediaminodielhylgold bromide is a colourless, stable salt having the 

 constitution 



CH.2— NH.2 Et" 



\ / 

 Au 



CH.— NH2 Et 



Br. 



In all these compounds, gold has a co-ordination number of foiir. 



