42 Mr. Redfield on the Rotary Action 
lique ; a direction of Fig. 2. 
wind which seldom N 
or never prostrates 
fences, even in the AS 
path of a tornado. 
Besides, near the 
centre of such an 
inward blowingtor- ___ — 
nado, where only I 
it could act on 
these fences with 
lateral force, such 
winds must neces- g; S 
sarily become neu- 
tralized both by 
blowing against each other and by turning upward to escape, 
thus having little effect at this point, within four feet of the 
ground. I say nothing here of the possibility of any winds 
blowing wth violence in such central and opposing directions; 
which I could never conceive: for the entire spaces between the 
centripetal lines of arrows must be conceived as being filled by 
the affluent winds, the lines only indicating their directions. 
But on the other hand, let us suppose a strong whirlwind 
passing in the same direction; the front half of which, both on 
and near the line pursued by its axis, must necessarily sweep 
laterally across this line, first xorthwardly towards f, if it be 
revolving to the left; and the last half of the whirl on its ar- 
rival will sweep southwardly towards e; which sufficiently ac- 
counts for the effects observed. That only the fence e was 
thus prostrated by the first wind of the tornado may be ex- 
plained by the protection afforded to f by the house, against 
the advancing whirl, and perhaps here, also, by the spirally 
upward tendency towards the centre, in the wind which thus 
came round the south-east corner of the house, prostrating e in 
its course. But on the passing of the axis of the whirl, the 
wind would recur with increased force from the opposite di- 
rection, upon the fence /, prostrating it towards e; while the 
latter, being already down, and in turn partially protected 
by the house, would remain as it first fell. 
In passing over the track of the tornado between Burr’s 
house and Providence river, several instances and groups of 
prostration were observed ; but owing to the open character 
of the grounds throughout most of the track, the memorials 
afforded by the trees were less frequent than have been seen 
in other cases. 
Near the Pawtuxet turnpike the tornado encountered a new 
