PRESIDENT'S ADDRESS. Ixxvii. 



adduced to show that where forests have been cut down brooks 

 have disappeared, and small rivers become useless, for power 

 purposes, from want of water, whilst in larger rivers flooding has 

 become more frequent, though at other times navigation suffers 

 for want of water. The serious results of the destruction of 

 forests on the Black Mountain, near Toulouse, in the Kazan 

 district of Russia, in Wisconsin, U.S.A., in the province of 

 Messina, in Sicily, and elsewhere, and the good and bad effects 

 of replanting, and subsequently cutting down, the fir trees on a 

 mountain side in the Canton of Berne were given in full detail, 

 and left little doubt of the connection between the cause and its 

 disastrous results. 



Investigations in France, Switzerland, Norway, Greenland, 

 North America, Africa, and elsewhere show that glaciers are 

 almost universally retreating, though they sometimes advance a 

 little for a short period. Some have been observed since 

 1860. 



Kites and balloons continue to be used for investigating the 

 upper air with valuable results. On one occasion a height of 

 21,100 feet was attained, six kites being attached to each other, 

 and a wire line of nearly 16,000 yards in length being used. 

 The minimum temperature recorded was 13 degrees Fahr., the 

 ground one being 41 degrees. The wind velocity at this height 

 was 56 miles an hour, that on the earth's surface being 18. 

 From kite investigations in the tropics there would appear to be 

 three strata immediately above the surface, which vary in the 

 direction of wind and other respects, the lowest being about 

 1,000 metres in height, and occupied by the trade wind. 



ELECTRICITY. 



A successful electrical exhibition was held at Olympia last 

 autumn, and the public showed their interest in this compar- 

 atively newly-adapted form of power by largely patronising 

 the exhibition, In England electric power distribution 



