October 18, 1895.] 



SCIENCE. 



515 



Derwentwater and Bassenthwaite belong 

 together as a shallow lake, divided by an 

 alluvial iiat; their average depth being- 

 only IS feet, and this average being only a 

 quarter of their maximum depth. The 

 other lakes form a deeper group, whose 

 average depth is 40 feet, while the average 

 depth of each one varies from 36 to 61 per 

 cent, of its maximum depth. The best 

 examples of this class lie in long narrow 

 valleys with steeply sloping sides, the 

 slopes being continued under water and ter- 

 minating on a flat bottom. The lakes as 

 a whole reach just as far as and no far- 

 ther than the beginning of the more level 

 country which skirts around the high- 

 land. 



DIUENAL VARIATION OF RIVER VOLUME 

 AND VELOCITY. 



Professor Brtjckner, of Berne, contrib- 

 utes a review of numerous observations on 

 the rivers of Switzerland to Petermaun's 

 Mitteilungeii (June and July, 1895,) which 

 result in showing that all the streams head- 

 ing in regions of melting snow or ice have 

 perceptible diurnal fluctuations in volume 

 and velocity. These are noticeable in the 

 Arve to the city of Geneva, the Rhone to 

 its mouth in Lake Geneva, the Aar to Lake 

 Brienz, the Reuss to Lake Lucerne, espe- 

 cially in midsummer ; the wave of high 

 water advances down stream at a rate of 

 three or four meters a second. Side streams 

 entering a trunk river at different points 

 tend to confuse the high water wave, but 



fail to obliterate it. While a particle of 

 ice requires decidedly more than a century 

 to move from the summit of the Jungfrau 

 to the foot of the Aletsch glacier, 29 km., 

 only twelve hours are needed for the water 

 to flow from the glacier down the Rhone to 

 Lake Geneva, where it remains on the 

 average about eleven years before resuming 

 its journey to the Mediterranean. 



GEOGRAPHY IN NORMAL SCHOOLS.* 



Teachers of geography in normal schools 

 will do well to consider Mr. Murdock's 

 plan of work at Bridgewater; not so much 

 because it can be immediately applied else- 

 where as because of the importance that it 

 attaches to local observation in geograph- 

 ical study, and because of the large share 

 of attention allowed to questions of origin, 

 structure, denudation and the like, which 

 are too often left to one side, as if fenced off 

 n a geological field where the geographer 

 must not trespass. Many references are 

 made to good materials. On the other 

 hand, the fault of too much method, thought 

 by many educators to be characteristic of 

 normal schoools, occasionally appeal's; as 

 in such a definition as " A picture of an 

 object is the representation on a surface of 

 the appearance of an object." Any scholar 

 in a normal school who needs tliis defini- 

 tion cannot be ready for serious geo- 

 graphical study. So sententious a truism 

 as " Geographical objects within the range 

 of vision must be observed; the product of 

 of the observation is knowledge," is an- 

 other sign of those normal school methods 

 in which a diluted psychology is mixed 

 with other subjects of study, to the dis- 

 tress and embaiTassment of the everyday 

 teacher. 



^W. M. Davis. 



Habvaed Univeesity. 



* Outline of Elementary Geography. By F. F. Mur- 

 dock, State Normal School, Bridgewater, Mass. Re- 

 vised edition. July, 1895. pp. 159. 



