ta of the Providence Tornado. 267 
Se ee 
The barn ig anid the shed h were destroyed, and the materials swept off toward 
the first named buildings. A corn-house, standing on the same side with the barn, 
is stated in the Providence papers to have been blown over to the west, but I can 
find no notes of my own respecting the direction of its fall. 
The effects here exhibited appear to me to be due to a pro- 
gressive whirlwind, revolving to the left; for we may notice, 
as in the New Brunswick tornado, a more onward direction in 
the trees prostrated on the right of the axis, d, m, n, 0, &c., than 
on the left side; while the outermost prostrations on the right, 
n, 0, point still more nearly than the average on this side, to the 
course of the tornado: And on the left side of the track we have 
the tree & in a direction inclined several degrees backward from 
the course of the storm. T'he value of these indications of whirl- 
ing action I have endeavored to point out in my remarks on the 
New Brunswick case. [This Journal, Vol. xtr, p. 70-75. 
At the front of the house a, however, were two slatted door- 
yard fences, extending from the house to the road. The fence e 
was overthrown northward toward /f, and the fence f in the con- 
trary direction towards e: both directions being transverse to the 
line of the axis, which passes between them. Such cases have 
been adduced as supporting a directly inward course of the wind 
in the body of the tornado; or, as indicating two bodies of oppo- 
sing wind meeting on a central line; but I draw a different con- 
clusion: = Fee Fi A 
Let Fig. represent, = PT 
Ys 
body of the tornado, — 
and let it be supposed 
as passing over the area. |, | ia 
of Fig. I, without re- ' S 
volving, so as the course 
of the center will coin- 
cide with the arrow Sy s 
which indicates the | 
course of the axis on sess 
that figure. It may thus be seen that on this hypothesis the 
wind must strike the fences e, f, either parallel to their length, 
or but little oblique : a direction of wind which seldom or never 
