130 The Realm of Nature CHAP, vni 



monsoons are well-marked but not very strong, although the 

 range of temperature is considerable ; but with an equally 

 great range the Sahara region of North Africa has a very 

 much slighter monsoon -raising power. The flatness of 

 these expanses of land and their low elevation partly account 

 for this ; the disturbing influence on atmospheric pressure 

 of the expanses of sea to the north is also important. 

 On the west coast of North America there are distinct 

 monsoons, but it is in Asia with its steep mountain slopes 

 rising from the sea that the monsoon blows with greatest 

 power, and in India the name was first applied. 



REFERENCES 



1 J. Aitken, "On Dew," Transactions R.S.E. xxxiii. p. 9 

 (1885); also Nature, xxxiii. p. 256 (1885). 



2 J. Aitken, "Dust, Fogs, and Clouds," Transactions R.S.E. 

 (i 88 1) ; also Nature, xxiii. p. 195 (1881). 



3 See note on Lemstrom's Aurora Experiments in Nature, 

 xxxv. p. 433 (1887). 



BOOKS OF REFERENCE 



W. Ferrel, Popular Treatise on the Winds. Macmillan & Co. 

 (An admirable discussion, but not easy reading.) 



R. Abercromby, Weather. International Scientific Series. 



