- 
On the Courses of Hurricanes. = 205 
lence will pertain to only one of the-phases which the storm 
presents, in its regular course over suchlocality. This may usu* 
ally be accounted for, by the interposition of land within the 
course of. the immediate cireuit which the wind is found to’ pur- 
sue ; and this result i is. perhaps most obviously exhibited in the 
South Atlantic or in the Southern Ocean, near the Cape of Good 
Hope, where the. barometric column, not unfrequently, subsides 
and commences rising, before the full violence of the gale takes 
effect. — _ The barometer, however, appears always to indicate the 
true extent and path of these whirlwind storms ; and I have 
found no good grounds to infer, that a hurricane contracts in the 
width of its path, while sweeping upon the surface of an open sea, 
_ 7. Another source of apparent irregularity in the changes of 
wind in these storms, arises from the interposition of one storm 
upon the path of another, in their passage through the temperate 
latitudes. . Col. Reid has shown something like shia in the hurri- 
cane which overtook the. Castries , August 24th, 1837, which was 
evidently impinging upon the 7 path of the great hurricane which 
had previously swept along the American coast. "That of the 
Castries appears to have pursued a course similar to the- hurricane 
of October Ist, 1830, as delineated on my first published chart ; 
thus advancing; by a shorter course, into the path of the larger. 
hurricane, and-probably with a greater progressive velocity. Col. 
Reid justly urges the -influence of, these causes in producing the 
irregular winds of the higher latitudes. Of the influence of such 
interposition i in apparently arresting or modifying the regular de- 
velopment of a storm while in progress, I have for many years 
been convinced ; but it is due to Mr. Espy, of Philadelphia, to 
mention,. wats so far 7. ote _ was the first to serene the 
——— 
racing cout ‘the path of iurrtaon we justly disc 
cory; and as the i tioh obtained of ‘their course a 
tent is. s cteteieae limited, and is acquired at different and 
tain periods, our delineations are, therefore, necessarily subject to 
minor errors and to subsequent corrections. Such corrections, I 
have ever found to be in favor of the uniform rotation and reg- 
ular course of progression, which have formerly been described. 
sr is probable, therefore, that the narrowed track, and somewhat 
oo: Journal of the Franklin Institute, Vol. xviu, a 1836, p. 239. 
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