SECTIONAL TRANSACTIONS.— B. C. B61 



3. Tiie conductivity is that of a salt, illustrated by hundreds of concordant 

 measurements with many kinds of soap. 



4. Half the conductivity must be ascribed to a constituent of very high 

 equivalent conductivity but of negligible osmotic pressure, the ionic micelle. 

 Its conductivity is several-fold that of all the fatty ions contained in it. 



5. By ultra-filtration tlie ionic micelle is found to be colloidal, and, in addi- 

 tion, the undissociated neutral colloid, consisting of still larger particles, may 

 be separated from the ionic micelle. Sodium and potassium electrodes confirm 

 the concentrations of sodium and potassium ions assumed. Migration determina- 

 tions are also in agreement. Hydrolysis is impossible in the case of cetyl 

 sulphonic acid, whose behaviour is closely similar. 



6. An important result is the theory of gel structure. The only differences 

 between a transparent jelly and a sol are mechanical — elasticity and rigidity. 

 The colloidal particles in both are identical in nature and amount, but in the 

 gel they are arranged in ultra-mici-oscopic filaments or aggregates. The 

 equilibria and the resistance to the passage of the electric current are unaltered 

 on gelatinisation. 



7. ' Electrical endosmosis ' and ' cataphoresis ' in a transparent soap jelly are 

 quantitatively identical with electrolytic migration in the corresponding soap 

 sol. 



8. The theoretical conclusions are of general applicability to very large groups 

 of organic and inorganic solutions in aqueous and non-aqueous solution. 



Tuesday, September 12. 



14. Discussion on The Nitrogen Industry. (See p. 415.) 



15. Dr. J. S. OwEXs. — Alvwspheric Dust. 



16. Rejiort oj the Fuel Economy Committee. (See p. 277.) 



SECTION C— GEOLOGY. 



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

 following list of transactions, see p. 408.) 



Thursday, September 7. 



1. Discussion on T]ie Geological History of the North Sea Basin, 

 (a) Opener : Prof. P. F. Kend-all. 



The North Sea is situated upon an area of very ancient and persistent 

 depression, dating probably from Permian times. Coal-measure rocks dip into 

 the Basin in Belgium and Holland, north of the anticline of Brabant; probably 

 in Lincolnshire; and certainly in Durham and Northumberland : they re-emerge 

 at Ibbenbiiren. 



The Permian rocks of Yorkshire and Lincolnshire increase steadily in thick- 

 ness from west to east. The Triassic rocks chow no significant change. 

 Members of the Jurassic and Cretaceous series attain their maximum develop- 

 ment in Britain in the area bordering the North Sea, and the Lower Cretaceous 

 beds exhibit a deep-water phase absent elsewhere in Britain. The chalk 

 thickens north and east of London partly by preservation of higher zones, and 

 partly by general expansion. In Yorkshire zone for zone it reaches its maximum 

 development, but in a deposit of this type this may not indicate contemporaneous 

 movement. 



The renewal of the Armorican movement in the South of England, Northern 

 France and Belgium appears to have begun after the deposition of the London 

 Clay and Woolwich Beds, and after some interruptions to have resumed its 

 activity at or about the beginning of Pliocene (Diestian) time. This may be 

 regarded as the first appearance of a North Sea as we know it. 



Harmer has suggested a coast-line connecting the Lenham and other outliers 

 spanning the Straits of Dover, joining up with the main Diestian outcrops of 

 Belgium. This view is accepted by the Belgian geologists and accords generally 

 with my own judgment, though not without some reservations. This may be 



