72 On the Whirling Action of the 
4. It has been noticed, also, that the directions given to bro- 
ken limbs and other bodies, by the successive changes in the di- 
rection of the wind as the tornado passed over, have been found 
in opposite courses of change, on the two opposite sides of the 
track. : 
This fact, too, has been strongly urged as disproving a rotary 
motion. But, unfortunately for the objection, this effect accords 
fully with the rotary action of a progressive mass of atmosphere; 
as is well known to all who clearly understand the theory of ro- 
tary storms. 
In all such whirling masses the successive changes in the di- 
rection of the wind, result solely from their progressive motion, 
and necessarily take place in opposite directions or courses of 
- change on a two opposite sides of the advancing axis. ‘This 
indicati ils, therefore, as a theoretic test; and I now proceed 
to notice , which are peculiar to a peogtedsive whirling ac- 
tion. £ 
5. In considering further the effects of such action, we may 
. expect to find that the greatly increased activity of gyration 
which is always observed near the centre of a vortex, will be 
indicated by a more violent and irregular action in and near the 
path pursued by the axis of the whirlwind, than is found under 
its more outward portions. 
This effect is often strikingly exhibited in the path of torna- 
does ; while, in the supposed ascent of a non-whirling column, 
it would seem that no part of the surface would be so much ex- 
empted from its action, and particularly from its power of prostra- 
tion, as that lying near its centre. 
6. As the effect of rotation must be to seotkticd, on one side 
of the advancing axis, a reverse motion which is contrary to the 
course of the tornado, it is evident that on this side the prostrating 
power will be much lessened ; that the cases of prostration, there- 
fore, will be here less numerous ; and that some of these, at least, 
will be produced in a backward direction, more or less opposite 
to the course of the tornado. By this criterion, not only the 
whirling movement, but the direction of the rotation also, may 
be clearly ascertained. 
This effect is best observed by comparing the two opposite 
margins of the track, and is strongly exemplified in the case be- 
fore us. Here we find, that most of the trees prostrated within 
ou. 
