eadily and strongly from a surface of snow
whose electricity is always positive. Hence it blows most strongly and
_continuously_ when snow has fallen at the north, and prevails during
winter very much in proportion to the extent and continuance of the
covering of snow which invests the earth in that direction. It follows
after storms, and particularly warm rains, during the autumn, winter, and
spring months, which have a lateral southern extension. Whether it is
increased by the snow from the surface from which it blows, or is caused
by the same magnetic action which causes the great fall of snow, is a
question we shall consider hereafter.

4th. It does not connect or mingle with the trade current in any way, or
change or divert the course of that current; but interposes between it and
the earth, elevating the trade in proportion to its own volume, above the
influences of the earth (when the trade becomes free from condensation,
and singularly, clear); and raising _proportionately_ the barometer. An
experienced observer can frequently estimate, with considerable accuracy,
the rise of the barometer, by measuring with his eye, (when the clouds
will enable him to do so,) the depth of this interposed N. W. current. The
barometer rarely rises after a storm, for twenty-four or forty-eight hours
if the wind continues at any point from S. W. to W. N. W., but always
rapidly as soon as the genuine N. W. current with any considerable depth
interposes and elevates the trade.

It will be obvious to every one, I think, certainly, if they will
hereafter study the subject and observe for themselves, that the N. W.
wind does not blow away the storm; and that it follows after it, blowing
over the surface which is uncovered by the storm; rarely, if ever, with
any force when the body of the storm passed south of us; and that it is a
purely surface wind, seemingly attracted by the peculiar magneto-electric
state in which the surface of the earth is left, compared with a snow-clad
surface to the north, by a recent storm, or that peculiar state of the
trade which is left by the action of the storm. It seems to follow that
magnetic wave which, passing from north to south, acts in its course upon
the counter-trade, producing the storm, or belt of showers, and giving
them their southern lateral extension, and will well repay future
telegraphic investigation. Its electricity is intensely positive--that of
the earth by the action of the storm as i