140 



THE MICHIGAN ACADEMY OF SCIENCE. 



an area where it is afternoon and consequently low pressure of the 

 atmosphere. The motion of the upper atmosphere is therefore eastward. 

 This is illustrated by my diagram of th^ atmospheric pressure by hours 

 of the day at Singapore, on the equator. The forenoon high pressure 

 and the afternoon low pressure generally in the torrid and temperate 

 zones are facts well known to meteorologists. So far as I know, however, 

 the explanation here offered has not heretofore been set forth. The man- 

 ner of constructing diagrams of the earth, as here planned, exhibiting 



Jivsi'age velocity of wind, at tanslng ,MicJiiqan,^3 

 years, /f^O- igoz. Sarth,J^. )ie-m'is^here,Luiihin in- 

 nei" circle; hours of day, hetu/een inner and Tniddle 

 circles ; miles of wind, hetu/een rniddle and outer cir- 

 circles, scale 1 mile yjt>er hour tojo inch, miles during 

 eaeTi hour, day and night, stated in figures outside 

 of outer circles . 



the facts by hours of the day. seems to nmke it possible to easily grasp 

 the relations of atmospheric pressure, wind, and earth's rotation. 



2. Another reason for questioning the common view as to the cause 

 of the eastward movement of the air in the temperate zones, is that the 

 same explanation that I have stated for the torrid zone is adequate to 

 explain the eastward movement in the temperate zone, namely, the fore- 

 noon high barometer, the afternoon low barometer, the afternoon always 

 being eastward from the forenoon, the wind blowing from the high toward 

 the low pressure, therefore eastward. 



