.^60 Sectional transactions.-b. 



4. The substitution-type is considered to have remained unchanged as loii^ 

 as there is formed more than 60 per cent, of ^^-o-compounds for the ^^-o-type and 

 more than 40 per cent, of the m-compound for the wt-type. 



5. Exceptions seem to be the introduction of ethyl into chlorobenzene by 

 tlie Friedel-Crafts reaction, where 65 per cent, of 7?)-ethylchlorobenzene i!» 

 obtained, and the mercuration-reactions of Dimroth. These exceptions are only 

 apparent. 



6. When there are two substituents, X and Y, already present in the benzene 

 nucleus the validity cf the rule can be judged only if the ratios in which the 

 isomerides are formed by the introduction of a second group into CeHsX and 

 into CeHiY are known. 



7. In the case of the presence of more than two substituents the application 

 of the rule becomes more difficult. 



Monday, September 11. 



11. Discussion on The Hydrogenation of Fats. 



Mr. E. R. BoLTOx. — Technical Aspects of Hydrogenation. 



The unfortunate state of patent law in connection with chemical processes, 

 as exemplified by hydrogenation, was briefly touched upon. 



Factory conditions were then dealt with, commencing with the problem of 

 hydrogen and its preparation (i) electrolytically, (ii) by coke methods, (iii) as a 

 by-product, and (iv) by hydrogen carriers. The relative merits of these methods 

 of production were discussed, passing to the necessary condition of tlie oil for 

 the most economic and efficient treatment, and dealing with catalyst poisons and 

 substances affecting the life of the catalyst. The catalyst itself, it was pointed 

 out, will always be the item of greatest importance, and the processes whereby 

 so much catalyst per ton is regularly lost will rapidly die, to be replaced by 

 those in which the catalyst is considered as a capital charge — in fact, a part of 

 the plant. Emphasis was laid upon the necessity of an efficient and skilled 

 scientific staff for the control and preparation of the catalyst and the examina- 

 tion of the raw materials used. Physical factors were then discussed brietiy, 

 including the engineering side and comprising problems of contact, solubility 

 of hydrogen in oil, and, finally, types of plant, in which connection it was pointed 

 out that it is only the continuous plant which is likely to find favour in the 

 future. Attention was drawn to the connection of all these issues with the cost 

 of hydrogenation. 



The different types of product required in the various industries, such as 

 the edible oil, soap, and candle industries, were dealt with, and, finally, sugges- 

 tions were put forward for further research and an indication of probable 

 developments made. 



12. Di'- R. WiiYTLAW Gray. — Gaseous Dispcrsoids. 



13. Prof. J. W. McBain. — The Sludij of Soap Solutions. 



In view of the large number of current theories which are irreconcilable 

 with the conclusions to which the study of soap solutions has led. it is necessary 

 very carefully to prove the evidence for the existence of the ionic micelle and 

 the theories arising therefrom. 



1. The following methods agree in showing that hydroxyl ion is only a minor 

 constituent of soap solutions, being only about O.OOIA^ : — 



(«) Electromotive force with hydrogen electrode. 

 (/)) Catalysis. 



(c) Conductivity. 



(d) Ultra-filtration with direct analysis of the filtrate. 



2. The osmotic activity is about half that of a salt. Trustworthy measure- 

 ments have been obtained by : — 



[a) Freezing-point. 



(b) Dew-point. 



(c) ■Minimum jiressure required for ultra-filtration. 



[d) Vapour pressure. 



