252 MR. THOMAS HOPKINS ON THE INFLUENCE 



wind alluded to, sometimes called a Pacific monsoon, 

 is found in the southern summer blowing from the So- 

 ciety Islands to Guayaquil ; and this is through (say) 86° 

 of longitude ; and, in the whole of this course, the air 

 moves eastward faster than the surface of the globe. 



It is only when the sun is in the southern hemisphere 

 that this latter Pacific wind is found blowing from the 

 west; but it then constitutes a regular monsoon, some- 

 times of considerable strength. At other times of the 

 year, the ordinary eastern trade-wind prevails over the 

 same range of the ocean. But if the east wind was caused 

 by the rotation of the earth leaving the air behind it, what 

 could cause the wind coming from the west to move to- 

 wards the east faster than the surface ? The rotatory 

 velocity of the surface is the same at all seasons ; and cer- 

 tainly it may be presumed that the cause, whatever it 

 may be, which makes the air rotate more rapidly than 

 the earth at one time, may be able to make it move either 

 more or less rapidly at another time, and in a different di- 

 rection. This, I have attempted to show, is the case in all 

 winds, — the disturbing power which causes them being 

 in action, in all cases, where the wind terminates. 



Another wind is said to be found blowing near to the 

 equator, across the whole Pacific Ocean from the west, into 

 the Gulf of Panama, and of course moving eastward faster 

 than the surface ; but enough has been said to show that 

 on the eastern sides of both the Atlantic and Pacific 

 Oceans well-known facts are to be found, which are di- 

 rectly opposed to the theory that the rotatory motion of 

 the globe palpably disturbs the movements of the air on 

 its surface. 



There are two assumptions generally made by meteoro- 

 logists which it is here contended are the offspring of the 

 imagination, and are in substance fallacious. One is, that 

 winds are produced by the unequal heating of different 



