-1859] 



WRITINGS OP JOSEPH HENRY. 



77 



western side of Europe is also warmer than the eastern side 

 of Asia does not explain the phenomenon ; it merely points 

 out an analogy, but not a cause. It is evident that the posi- 

 tion of the mountain system, and the direction of the ridges 

 with reference to the prevailing winds, must have some con- 

 nection with this phenomenon. In addition to this, the 

 westerly aerial current, as it is principally derived from. the 

 equatorial regions, must in itself be warmer than the tem- 

 perature due to the latitude of the belt in which it is mov- 

 ing. It will be well, therefore, before proceeding to this 

 branch of the subject, to give a brief statement of some of 

 the results which have been reached by deductions from 

 actual observations in regard to this powerful agent in mod- 

 ifying climate. For the materials used for this purpose we 

 are indebted to the valuable labors of Prof James H. Coffin, 

 of Lafayette College, the results of which have been pub- 

 lished by the Smithsonian Institution.* 



In order that the facts may be the more readily compre- 

 hended, and produce a more indelible impression upon the 

 mind, since ideas received through the eye are the most defi- 

 nite and lasting, we shall represent the direction and amount 

 of the wind by means of diagrams such as are exhibited in 

 the accompanying figures. The lines indicated by the letters 

 N. E. S. W. represent the cardinal points of the compass, 

 and the breadth of shading along any of these lines the rel- 

 ative amount of wind in the course of a given period ob- 

 served at a particular place. 



Thus for example in No. 1, in the circle on the right hand 



No. 1. 



New York. New England. 



Summer. Winter. Summer. Winter 



*["The Winds of the Northern Hemisphere." 4to. 198 pp. 

 and platea. Smithsonian Contributions to Knowledge; vol. vi.] 



13 maps 



