774 KEPOET — 1893. 



sources. This method gave a sense of the reality of the work scarcely attainable 

 otherwise. 



Practical petrological work he had found generally popular with professional 

 students — much more so than palaeontological museum work, some of which must, 

 however, of course, be done. 



He thought that much more use than is commonly the case might be made of 

 the experimental method in teaching students of this class. He found, for instance, 

 that a machine designed by himself for the reproduction on the lecture-table of 

 most of the phenomena connected with folds, faults, and thrusts gave great 

 definiteness to the ideas of his pupils, and at the same time added very much to 

 the interest taken in the lectures. This was the ease also with many of Daubr^e's 

 experiments on lamination and foliation, and on joints produced by torsion, which 

 could easily be adapted for demonstration purposes. The fact that sediment is 

 deposited more rapidly in salt than in fresh water once seen is never forgotten — 

 if only mentioned it is seldom remembered. The production of tinstone (cassiterite) 

 in a porcelain tube from chloride of tin and water vapour can be managed within 

 an hour's lecture, and impresses upon the student's mind one method of vein-filling 

 from below in a manner uneqiialled by any amount of talk. The synthesis of 

 several minerals can also, with a little trouble, be carried out with the best effects 

 where a friendly chemical or metallurgical laboratory is at hand. 



Added to experiments such as these, actual measurements with goniometers, 

 observations of specific gravity by various methods, testings of hardness, streak, 

 fusibility, and the like, should be made ; and now that we had the benefit of 

 Professor Cole's most excellent * Aids in Practical Geology,' they could be made with 

 much greater ease than formerly. 



Time precluded the author from entering into further detail, but he trusted 

 that enough had been said to show that in teaching professional students of the 

 University College order he was inchned to rely very largely upon general 

 principles, illustrated as far as possible by lecture experiments and by actual work 

 done by the students themselves in the field and geological laboratory. 



2. The Glaciation of Asia. By Prince Keopotken. 



There has lately been a good deal of discussion about the glaciation of Asia^ 

 and especially of Siberia. 



To speak of the glaciation or non-glaciation of an immense continent, without 

 taking into account its orographic structure, is evidently utterly misleading. One 

 must have first a clear idea of what Asia is from the orographer's point of view. 



I have, therefore, marked what is known about the glaciation of Siberia upon 

 a map, in which Petermann has embodied the ideas I advocate about the oro- 

 graphy of Siberia. The different tints with which it is coloured will show at a 

 glance the structure of that part of the continent. 



Lilac represents the plateau (12,000 to 16,000 feet high in the south, 4,000 ta 

 .5,000 feet high in the north), with a depression — the lower plateau— coloured in 

 a lighter shade of lilac. Deep and broad valleys penetrate into it from the west. 

 They have been its drainage valleys. The high plateau has never been submerged 

 since the Devonian age. 



Broivn colour represents the border-ridge of the plateau and the Alpine tracts,. 

 indented by deep valleys, which fringe the plateau and consist of chains rimning 

 north-east (the older ones) and north-west (the younger ones). 



Orange-yellow represents the high steppes and prairies, 1,000 to 2,000 feet 

 high. 



Green shows the lowlands under 1,000 feet, and mostly under 500 feet, above 

 the sea. 



Now, taking into consideration all that is known about the old glaciers of 

 Siberia, we may, I think, sum it up as follows : — 



The lowlands, in all probability, have not been glaciated. Immense portions of 

 them were under the sea, perhaps during the Glacial age, and most certainly 



