Page:Popular Science Monthly Volume 50.djvu/128

116 Other articles confirming the position first taken followed, among them one on the hurricanes and storms of the West Indies and the coast of the United States, and the uniformity of their general character, in which the storms of the China Sea were shown to be similar to those of the West Indies, and the gyrations in the southern hemisphere to be opposite to those in the northern; one presenting a general view of the atmosphere and its currents, and a classification of storm winds, predicating the identity of whirlwinds and water spouts, and discussing the great aërial currents; and articles on tidal movements, climate as connected with atmospheric and oceanic currents, the Gulf Stream, and polar currents.

The main features of Mr. Redfield's theory of storms, as stated by Prof. Olmsted, are:

"That all violent gales or hurricanes are great whirlwinds, in which the wind blows in circuits around an axis either vertical or inclined; that the winds do not move in horizontal circles, but rather in spirals toward the axis—a descending spiral movement externally and ascending internally.

"That the direction of revolution is always uniform, being from right to left or against the sun on the north side of the equator, and from left to right or with the sun on the south side.

"That the velocity of rotation increases from the margin toward the center of the storm.

"That the whole body of air subjected to this spiral rotation is, at the same time, moving forward in a path at a variable rate, but always with a velocity much less than the velocity of rotation, being at the minimum, hitherto observed, as low as four miles, and at the maximum forty-three miles, but more commonly about thirty miles an hour, while the motion of rotation may be not less than from one hundred to three hundred miles per hour.

"That in storms of a particular region, as the gales of the Atlantic or the typhoons of the China Sea, great uniformity exists in respect to the path pursued; those of the Atlantic, for example, usually issuing from the equatorial regions eastward of the West India Islands, pursuing at first a course toward the northwest as far as the latitude of 30°, and then gradually wheeling to the northeast and following a path nearly parallel to the American coast, to the east of Newfoundland, until they are lost in mid-ocean, the entire path when delineated resembling a parabolic curve whose apex is near the latitude of 30°.

"That their dimensions are sometimes very great, being not less than one thousand miles in diameter, while their path across the ocean can sometimes be traced for three thousand miles.

"That the barometer, at any given place, falls with increasing