On the Rotary Action of Storms. 69 
radius, and therefore is deflected northwards and strikes north of 
the centre. ‘The breezes from all quarters thus co-operate to pro- 
duce the result; and all their forces are constant, and act with 
precision and at great advantage to cause and maintain.a whirl- 
wind. A diagram presenting the lines of approach of the parti- 
cles or streams of air, will explain this result. 'The black lines 
in figure 2, show the deviating currents, from the cardinal points 
alone, when the area affected by the fire is so small as to require 
no perceptible curve in those lines. 
Fig. 2. 
Upon the same principle, the tornado, the typhoon, and the 
wide-spread storm of the Atlantic, if their currents move towards 
a central spot, must have a rotary character. The circular mo- 
tion in the outer portions may be slight, but it is stronger near 
the centre. In every such case the incoming air may be regarded 
as a succession of rings taken off the surrounding atmosphere, 
and moving slowly at first, but swifter as. they proceed towards 
the centre. Each such ring is affected by the law of deviation 
during its passage. The particles are veering from the radii, in 
its northern quarter westward, in its southern quarter eastward, 
in its eastern quarter northward, and in its western quarter south- 
ward; and hence the ring begins to revolve when far from the 
centre, turns more and more as it draws near it, and finally as it 
gathers about the central spot all its forces are resolved into a 
simple whirl. Ring after ring succeeds, and the whirling action 
is permanent. © 
