Causes determining the Courses of Storms. 13 
Absence of a Brisk Trade Wind on the Southern Margin of 
the Storm. 
We may infer from the reports of the Brig Rolla and H. M. 
Ships Pilot and Ringdove, that calms and light winds prevailed 
in the Caribbean Sea and on the southern margin of the storm 
during the observed progress of the latter. ‘The usual prevailing 
course or tendency of the lower currents of air, in these regions, 
at least in the hurricane months, appears to be from a point south 
of east, instead of north of east, as is often supposed.* ‘This 
general tendency towards some point which is north of west must 
usually control the courses of the storms in this region. But the 
lightness of the surface winds of the Caribbean Sea at this period, 
*T} tained , long since, from logbook blished i ] d tical di tori 
that the course of the trade-w inds, at their inferior surface, i is often parallel to aa even 
one ate or more from the equator ; particularly inside the tropics. From the 
s, by intelli 
s of the 
Indies, : have also learned, that the course of the | lower cloud currents is often, if not gen- 
of ‘the W. st India hurricanes has demonstrated the northwesterly tendency or courses of 
of the aes currents, viewed as a whole, in these regions. 
r. Lawson, in Jameson’s Edinburgh Phil. Journal, for July, 1845, has given the on 
wane, of his observations both on the surface bya and cloud currents at 
13° 10’ N., in 1841; from which it appears that from May to September inclusive, the 2 
servations on the surface winds, made at bias ii have resulted, numerically, as 
follows: viz. N. W. wind, $ N.2; N.N.E., 4; N.E., 18; E.N. E., 106; E., 122; 
. E., 66; 8. E441; 8.8. BE, 13; S., +18: W., 2: the E. N. E. being the most 
quent wind ae o rr while the S. E. and S. S. E. winds greatly predominate over 
those sec N. Es ‘ 
the cloud til ting and important. Com- 
pat tables of these are eiven for September se feeds ach may be taken for nearly 
erage months, as betw ummer and winter. Two or more currents commonly ap- 
seared: — the sillace’ wit a ower current from south of east and a higher one Pero 
S. W.; of which, as well a in non should be 
viewe d as sy othe niga to = ee atmosphere. The numerical results for 8 two 
months were as follows: 
Abstract of Observations ¢ the Surface Winds and Cloud —— at Barbadoes, in Sep- 
tember and October, 1841, (Observations taken at5a.m.; 10a. M.; 3P.M., and 9 P. M.) 
roe Noc* |winds.|Cloud currents.{Totals.) From what” (winds. |Cioud currents.|Totais. 
Ww. N. W. ] E. 8. E. 21 8 2 
N. W. 5 5 8..E, 29 26 55 
N. = w. 1 16 17 8. S. E. 4 SI 35 
1 18 19 8. 3 ul 14 
N. ¥. E. 3 4 9 ‘Ss. S. W. 1 6 7 
og! 12 9 21 w. 89 89 
90 16 106 W.s. W. 1 6 4 
Rens sterly § 109 109 69 173 Seuthea: Rete che § 59 177 236 
Tea Eat be i ee ea ee AED 
These, with a vast extension of similar phenomena, merit the serious attention of those 
naturalists who rest on the calorific theory of the general and trade winds ; and they seem 
fully to account for the northwesterly courses of storms inthe West indies. 
