114 Observations on the Storm of Dee. 15, 1839. 
which pertain, more or less, to many of the storms or gales that 
visit the United States and other regions. These characters have 
claimed attention from almost the earliest period of my inquiries. 
1. The body of the gale usually comprises an area of rain or 
foul weather, together with another, and perhaps equal, or greater 
area of fair or bright weather. 
2. The fall of rain or snow often extends, in some direction, 
greatly beyond the observed limits of the gale. 
3. The gale itself not unfrequently exhibits an apparently un- 
equal extent of action, or degree of violence, on different sides of 
its apparent axis of rotation. - cee 
This peculiarity, as well as the second, is most commonin 
winter storms, and in those which sweep over an extensive con- 
tinental surface ; and, like other irregularities, is less noticeable : 
in the storms which are traced solely on the ocean. 
e barometric indications of a gale commonly ented 
same pee the observed limits of its action. 
5. The body of the gale constitutes a determinate sheet or 
stratum of moving air; and of this. sheet or stratum a large por- 
tion sometimes overlies another and more quiescent stratum of 
air, the latter having, perhaps, a different motion ; as may be of- 
ten observed in the common winds of the temperate and higher 
latitudes: in which case the gale is either not felt at the surface 
of the earth, or the observed changes of wind are found, in part, 
unconformable to the whirlwind theory. 
6. Owing to the convergent and somewhat variable éondeoaii 
storms in the extra-tropical latitudes, as well as to their unequal 
rates of progress, two storms will sometimes cover, in part, the 
same field, one of which will overlie the other, and, perhaps, # 
thin out at its margin, in the same manner as common winds. = 
This, also, may occasion a different order of change in the ob- 
served winds and weather from that which is commonly noticed 
in a regular whirlwind storm. 
Owing to such causes, the oscillations of the barometer are of 
ten irregular ; and this is particularly noticeable in the higher 
latitudes. 
7. In most gales of wind there-is, probably, a subordinate mo- 
tion, inclining gradually dowiswaed and inward in the circamja- 
cent air, and in the lower portions of the gale; and a like degree 
of motion, spirally upward and outward, in the central and higher 
portions of the storm. This slight vorticular movement is be- 
