Local Barometric Curves of the Storms. 317 
the group of storms which appeared on the European coasts 
about the 10th of October. 
caL Curves or Pressure purING THE Procress oF THE 
SEVERAL Storms.—T'he barometric observations at various points 
on or contiguous to the track of the Cuba hurricane from the Ist 
to the 7th or 8th of October, in the order of distance from its 
center-path, are delineated on Plate XI, fig. 21. This order of 
axial distance cannot be combined with that of the storm’s pro- 
gression, but the latter order is indicated by the numbers annexed 
to the several places of observation. The rising of the barome- 
ter, after its depression in the first Cuba storm and that of the 
lakes, is here seen to have been interrupted or prevented by the 
depressive effect of the hurricane which followed. In the first 
storm the fall of the barometer is seen to increase, northward of 
the Carolinas, in approximating with the route and the wide 
Spreading influence of the storm from the basin of the great lakes, 
- S80 that from New York to the mouth of the St. Lawrence the . 
barometric depression was greater than was subsequently found 
in the left margin of the succeeding hurricane. In fig. 22, Plate 
XI, the same barometric curves are all adjusted to one point of 
advance in the Cuba hurricane, for the purpose of facilitating the 
comparisons. The several distances from the axis line are noted 
m the right hand column. ' 
The importance of these extended observations, as affording 
Some explanation of the causes and character of the irregular 
barometric undulations which occur in temperate latitudes, in- 
duces me to exhibit, in fig. 23, Plate XI, a delineation of the lo- 
cal curves in the track of the third or Lake storm; showing, as 
We approach the seaboard, the united barometrical effects of at 
two storms as they are found converging in their course. 
The distances of the several places of observation from Halifax 
ate noted on the Plate, beginning at Lake Superior. The route 
of this Lake storm appears to have been nearly parallel to that of 
3 si storm of Nov. 11th, 1835; which is found on Chart I, mark- 
ed XT. : 
Thus it appears that two different storms may at one period in 
course of their progression, be found moving 1n the same 
_ 8€0graphical area, even when their several places of origin have 
been greatly distant from each other. Their convergence in such 
May result from different courses of progression, as well a3 
5 
