On the Rotary Action of Storms. 67 
deviates eastward from the meridian, and ultimately describes 
over the earth’s surface a curved line bearing towards the east. 
A current of air from latitude 45° north, having a due south di- 
rection, soon reaches regions moving faster to the east, falls behind. 
them anit describes a curve to the west. Winds oblique to 
meridian are similarly affected. These familiar matter 
ferred to here, and illustrated by figure 1, to elucidate what fol 
lows, 
Fig. 1. 
east and west winds, must also be considered. A carla of 
itude, being a lesser circle of the globe, and at all points equall: / 
distant from the pole,’ necessarily describes upon the earth’s sur- 
face a curved line. But a direct course, due east at the com- 
mencement, follows a great circle, and parting from the parallel 
reaches a lower latitude, ‘The due east course continued in a 
right line describes a tangent to the curve of the latitude. The 
Velocity of the earth’s surface at any place, by virtue of the di- 
urnal revolution, has for its direction the line of that tangent ; 
and when the air reposing over any spot is transferred to a region 
of diverse motion, the direction, as well as the degree, of its pre- 
Vious force is to be taken from that of the soil on which it: pre- 
Viously rested, Hence a wind from due west, if in our hemi- 
Sphere, will soon be found pursuing a southeasterly eet and 
crossing successive lels of latitude. 
iaonere of ney have been directed to the esata 
of a central ascending column of rarefied air, and centripetal eur- 
rents from every side rushing towards its base. Without pursu- 
ing his reasoning, it will be safe to assume that his collection of 
facts established the existence of a qualified central tendency of 
the air, in both the general storms and the smaller tornadoes. 
