OCTOBEE 18, 1895.] 



SCIENCE. 



501 



scribed by Mr. Montagu Browne, and Mr. 

 Harrison reported on the flints, supposed 

 by himself and others to have been worked 

 by man, obtained from high level drift in 

 Kent. Mr. Walford gave an account of tlie 

 succession of rocks occurring between the 

 Inferior 051ite and the Great Oolite in Ox- 

 fordshire as revealed by an excavation 

 undei'taken there within the year. In a 

 paper on the auriferous conglomerates of 

 Witwatersrand Dr. Hatch concluded that 

 the gold must have been introduced into 

 the rock subsequentlj'' to its consolidation, 

 and not derived with the pebbles from an 

 older formation. 



Professor J. Milne, in an exceptionally 

 interesting paper on earthquake phenomena, 

 showed that the greater shocks could be 

 felt by delicate instruments for enormous 

 distances, even at their antipodes, and that 

 the waves travelled faster than if the in- 

 terior of the earth had the elasticity modulus 

 of glass or steel. The observations of slight 

 movements showed one regularly recurring 

 set which the writer suggested might pos- 

 sibly be due to the evaporation of moisture 

 by day and its deposit by night. The Com- 

 mittee engaged in collecting photographs of 

 geological interest had amassed not less 

 than 1,200, which were deposited at the 

 Museum of Practical G-eology at Jermyn 

 St., London. Gradually this collection will 

 form a most valuable and reliable survey of 

 geological features and phenomena. 



The committees on the erosion of sea 

 coasts and on the circulation of under- 

 ground water completed the labors on which 

 they have been engaged for so many years, 

 but still continue to act and now pro- 

 poses to extend its scope to Scotland, where 

 the local committee has ceased work for 

 some years. 



Amongst the papers on glacial subjects 

 one of the most important was by Professor 

 Sollas on artificial glaciers (or ' poissiers ') 

 made of pitch, and their bearing on the- 



ories of glacier movement and transport. 

 Troughs were prepared of various shapes 

 and while these were inclined they were 

 filled with pitch in such a way that when 

 placed in position its surface had a sloj)e of 

 about 12 degrees. The pitch was put in in 

 layers, various substances, such as rice, 

 sago, pigment, etc., being placed on each 

 layer as it was completed, to serve as in- 

 dexes of the movements within the mass. 

 In this way it was shown that against bar- 

 riers opposed to the movement of the ice, 

 an upward movement occurred like that 

 which had long since been postulated by 

 geologists to account for the upward trans- 

 port of erratics. A similar upward move- 

 ment also was detected in the pitch where 

 it was driven into a narrow gorge. Another 

 point illustrated was that pitch sometimes 

 overrode heaps of loose materials just as 

 glaciers are known to override their mo- 

 raines. Pitch conformed to all the laws of 

 fluid motion and differed only in the ele- 

 ment of time, and it was found that prac- 

 tically similar results could be obtained 

 with Canada balsam, glycei-ine and even 

 water. This enabled Professor Sollas to 

 project on the screen not only photographs 

 of his results, but the actual experiments 

 themselves taking place. The author had 

 been able to imitate experimentally some of 

 the phenomena recently described by Mr. 

 Chamberlin. 



Several papers dealing with old, pre- 

 Glacial valleys were read. One by Mr. 

 Beeby Thompson called attention to the 

 following varieties of such valleys : (1) 

 New valleys without drift and having old, 

 filled-up valleys near at hand; (2) Those 

 that drift on one side and rock on the other; 

 (3) Streams re-excavating old, drift-filled 

 valleys; (4) Re-excavated valleys with the 

 drift all washed down into gravel. Mr. E. 

 Hill described a similar valley in Suffolk, 

 and Mr. T. V. Holmes one in Essex. 



Mr. P. Kendall and Mr. Lomas read a 



