346 SECTIONAL TRANSACTIONS— E. 



standard of warmth demanded for Koppen's ' Olive climate ' ; finally, rigid 

 adherence to the Koppen criterion of a tundra climate would entail the 

 classification of the western coast of Chile south of 52° S. in the tundra 

 climates (as has been done in Koppen's latest map in the Handbuch der 

 Klimatologie , Band 5, Teil G), in spite of the fact that frost is rarely experi- 

 enced along the coast. 



It is shown that, by a consideration of mean maximum as well as of mean 

 monthly temperatures, satisfactory delimitation of the temperature divisions 

 of the Chilean climates can be made. But it is also shown that the criteria 

 which apply to certain of the regions are not applicable to other, generally 

 similar, areas — in fact, certain of the Chilean regions have no exactly 

 comparable homoclimes. 



In these circumstances, a larger question is raised — namely, the possibility 

 of obtaining a satisfactory climatic classification to apply to both hemispheres. 

 As a basis of discussion new maps of isonomalous lines are prepared. These 

 are constructed for the midwinter and midsummer months for the world, 

 and show departures from the average temperature of the parallels irrespec- 

 tive of the hemisphere in which they occur. It may be called a map of total 

 isonomalies in order to distinguish it from the map of isonomalies in which 

 departures from the average temperatures of the parallels of each hemi- 

 sphere are mapped. The former is much more significant from the view- 

 point of classification, as it throws into full relief the difference between 

 climatically comparable — but not necessarily really similar — areas of the two 

 hemispheres. 



Capt. T. E. LoNGFiELD. — The subsidence of London. 



The paper deals with surface subsidence in the London district. This 

 subsidence has been confirmed by a recent, and still continuing, relevelling 

 of London. 



The principal lines of levels in this area have been completed, and it is 

 from these that the deductions have been made. 



At the same time the opportunity has been taken of comparing the results 

 which were obtained when levelling was carried out in 1865, 1895 and 1914. 



A comparatively new method is described by which levels can be trans- 

 ferred across water up to distances of about a mile, as this method has 

 enabled the levelling network to be connected with accuracy across the 

 estuary of the Thames at Dagenham and Tilbury. 



In addition to the more or less general sinkage disclosed in the London 

 area a number of cases of purely local subsidence have come to light and 

 are described. 



Mr. E. Jacobs. — The Hull fishing industry. 



This paper gives prominence to certain aspects of the Hull fishing indus- 

 try. The foundation of the trawl fishing at Hull, by Brixham fishermen, 

 some eighty years ago, is noted. This is followed by a survey of the geo- 

 graphical expansion of fishing operations, and the factors responsible for 

 the same are discussed. 



In conclusion, the most recent developments of the industry and its 

 allied undertakings receive comment. 



Afternoon. 

 Excursion to Coxwold, Ampleforth Gap and Rievaulx. 



