14 Character of Rotary or Vortical action in Storms. 
when viewed in connection with the strong trade or northeasterly 
wind which we have noticed as then existing in more northern 
parallels of latitude, may be deemed sufficient to account for the 
unusual west course of this hurricane. 
The hurricane of August and September, 1842, which has 
now been considered, caused great injury to commerce and the 
total loss of many vessels with their crews. 
What is meant by Rotary or Vortical Action in Storms. 
When in 1830 I first attempted to establish by direct evidence 
the rotative character of gales or tempests, I had only to encoun- 
ter the then prevailing idea of a general rectilinear movement in 
these winds. Hence I have deemed it sufficient to describe the 
rotation in general terms, not doubting that on different sides of 
a rotary storm, as in common rains or sluggish storms, might be 
found any course of wind, from the rotative to the rectilinear, 
together with varying anaes as regards clouds and rain. 
But I have never been able to conceive, that the wind in vio- 
lent storms moves only in circles. On the contrary, a vortical 
movement, approaching to that which may be seen in all lesser 
vortices, aerial or aqueous, appears to be an essential element of 
their violent and long continued action, of their increased energy 
towards the center or axis, and of the accompanying rain. In 
conformity with this view, the storm figure on my chart of the 
storm of 1830* was directed to be engraved in spiral or involute 
lines, but this point was yielded for the convenience of the en- 
graver. Some indication of the character of a great vortical 
movement is found in the arrows of the storm figures on my 
chart of 1835, on tracks I, V, and VIL+ In Vol. xxxv, pp. 203- 
205, of this Foniial and Vol. xu, p. 114, I have ngheed, curso- 
ae the variable as well as vortical conditions which pertain to 
great storms. Some of the effects of vortical rotation are also. 
discussed in my account of the Providence tornado. 
The common idea of rotation in circles, however, is sufficient- 
ly correct for practical purposes and for ihe construction of dia- 
grams, whether for the use of mariners or for determining be- 
§ "Piss Journal, Vol. xx. The dotted part of this figure was intended to indicate the 
area of rain. 
t See storm figures in this Journal, Vol. xxxt, p. 117, and Vol. 214. 
t Vol. xuiu, p. 271—275, ee 
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