these and similar facts, it seems impossible to doubt that the greatest violence of action was in an upward and easterly direction."

If these surprising results, which have been long the subject of observation, are so easily accounted for on the principles laid down by Mr. Espy, so, also, are all the other phenomena of these wonderful storms. We often hear of sticks, grass, sand, &c., frozen in the hail which falls from one of these clouds, and the curious fact has given rise to much speculation. The solution is now, however, perfectly simple. The current of ascending air which dashes with such fearful velocity upward into the cloud, and carries with it these lighter substances from below, also carries up the water which has been condensed from the saturated air, and throwing all out together at the side of the cloud in the region of congelation, they are frozen together in the form of hail, and descend by their own gravity to the earth. Large sheets of water may also be thrown out and frozen in the same way, which, breaking in their fall, will account for the great hail stones and "pieces of ice" spoken of by Howard, which fell at Salisbury, and for the "pieces of ice" of almost every form which fell during the passage of the Orkney spout in 1818.

Again: it is not uncommon for rain and hail to fall from one of these clouds in two distinct veins. Mrs. Tillinghast of Providence, during the passage of the tornado of 1838, saw two showers descending from the cloud, both of which sloped inward towards the spout which hung from the centre of the cloud below; and M. Pouillet has given an account of a hail storm which travelled from the Pyrenees to the Baltic, in 1788, leaving two veins of hail about fifteen miles apart, in which space there was a great rain. The eastern vein was about seven miles in width; the western about twelve, and on the outside of both was also a strip of rain. This storm progressed at the rate of about fifty miles per hour; the hail fell in no one place for more than eight minutes: the largest of them weighed eight ounces. We copy the chart of this storm below, as it appeared in the memoirs of the French Acadamy. A. A. A. are veins of rain; B. B. are veins of hail.—(For Chart, see next page.)

Mr. Espy, in his remarks on these singular phenomena, says :-"If I had made this storm myself, it would be said that I had made it to illustrate my theory. For it is manifest that the outspreading of the air above, will, in many cases, carry with it the hailstones; and those which are least the farthest, and these smaller hailstones on the outside of the bands, will melt before they reach the earth, while the larger hailstones, falling more swiftly, and having more ice to melt, may reach the earth in the form of hail. Thus the two veins of hail, and the rain on the outside of them, are manifestly accounted for; it is not quite so plain why it should only rain in the middle. Nevertheless, if we consider that the vortex moved with a velocity of fifty miles an hour from the southwest to the northeast, we will readily perceive that, as it would require perhaps twenty or thirty minutes for the drops of rain to be carried up to their greatest elevation, and to fall down to the earth, during which time the upmoving column would move forward twenty or twenty-five miles, neither hail nor rain could appear in front of the vortex, and as it could not fall in the middle of the spout, being prevented by the force of the ascending air, whatever fell between the two bands of hail must have descended in the hinder part of the ascending column, where it would not be likely to descend, on account of its upper part leaning forward."

VOL. V.-NO. IV.

44

These lofty clouds, whether formed over land or water, when the dew point is very near to the temperature of the air, appear to let down from their bases a tongue of vapor in the form of an inverted cone, which has been called a spout. Mr. Espy, in his explanation of this phenomenon, says: "If, however, the air is very hot below, with a high dew point, and no cross currents of air above to a great height, then, when an upmoving current is once formed, it will go on and increase in violence as it acquires perpendicular elevation, especially after the cloud begins to form. At first the base of the cloud will be flat; but after the cloud be comes of great perpendicular diameter, and the barometer begins to fall considerably, as it will do from the specific levity of the air in the cloud, then the air will not have to rise so far as it did at the moment when the cloud began to form, before it reaches high enough to form cloud from the

He says: "The atmosphere was filled with low, ashy-colored clouds, some of which were darker underneath than others, and from these the water-spouts were generally formed, each one from a separate cloud. In some instances, they were perfectly formed before we observed them, but, in others, we could see a small portion of the cloud, at first extend downward, in the shape of an inverted cone, and then continue to descend, not very rapidly, until it reached the water. In other instances, however, we observed that this conical appearance of a portion

of the cloud did not always result in the perfect formation of a water spout. Several times we saw the cone project, continue for a short time stationary, then rise again slowly, and disappear in the clouds. This would, in some cases, occur two or three times to the same cloud; but, eventually, a larger and darker cloud would descend, and result in forming the visible spout, as above mentioned."

It will be seen at a glance, that the principle on which Mr. Espy explains the phenomena of nature in the production and development of storms, requires the convergence of the winds towards a common centre or line at the base of the cloud. In this he differs materially from Mr. Redfield, who has been at great pains to show that all storms are whirlwinds, and that the air moves around from right to left, or contrary to the hands of a watch. On this point there is still much controversy, but we have no room to enter on the merits of the discussion in this article, and shall content ourselves with exhibiting some of the facts on which Mr. Espy relies to establish this, one of the main pillars of his theory.

As the violent action which attends tornadoes is generally confined to very narrow limits, these storms seem to furnish the best means for testing the truth of these different theories. It is, we think, clear that if the wind moves around a common axis in the form of a whirl, that the trees which are thrown down on the borders of the storm should lie parallel to its path, while those which fall in the centre should be left in a transverse position, or at least be thrown outwards and forwards on one side, and outwards and backwards on the other. Now it would seem from a great variety of testimony that the trees in these violent storms are not prostrated in the above named direction.

President Bache, of Girard College, after having carefully taken the direction in which the trees fell in the New Brunswick tornado with a mariners' compass, says :-"I think it entirely made out, that there was a rush of air in all directions at the surface of the ground towards the moving meteor; this rush of air carrying objects with it. The effects all indicate a moving column of rarefied air, without any whirling motion at or near the surface of the earth."

Professor Loomis,* of the Western Reserve College, after drawing a map of the trees and buildings which fell in a hurricane that passed over Stowe in Ohio, comes to a similar conclusion. "It will," he says, "then appear from an inspection of the diagram, that in the midst of some disorder there was a degree of uniformity. Thus upon either border of the track the trees all incline towards some point in the centre of the track. There is not an example of a tree being turned outwards from the track, nor even one which lies in a direction parallel to it." He afterward adds, "We have now established, by a fair deduction, that there was a powerful current of air from the opposite sides of the track towards some point in the centre of the track, and that here there was also a powerful current upward.”

Professor Olmsted,† of Yale College, in his account of the New Haven tornado, which occurred on the 31st of July, 1839, says :-"The first great fact that strikes us, is, that all the trees and other objects that mark the direction of the wind which prostrated them, are, with a very few ex

Professor Loomis is not an advocate of Mr. Espy's theory.

+ Professor Olmsted is not a believer in Mr. Espy's theory

ceptions, turned inwards on both sides towards the centre of the track; while near the centre, the direction of the prostrate bodies is coincident with that of the storm."

Professor Forshay in his account of the Natchez tornado is equally in point. He declares that "the nearer the axis of the tornado, the nearer were their bearings parallel with that axis, and the more remote, the nearer perpendicular, while those that point to the direction from which the storm came, or cross a line perpendicular to the axis, lie beneath those that point in the forward direction of the same."

We may mention also, that the storm which occurred in France, of which we have given a chart in the former part of this article, could not possibly have been of the whirlwind character. Had the wind moved in a whirl, the hail which fell during its progress, must have been scattered over the whole area of the storm, and not been deposited in two veins for many miles as we have seen. If the whirlwind theory is correct, therefore, this storm at least must have been a wonderful exception to the general law.

But Mr. Espy does not rely alone on the direction of fallen trees in tornadoes to prove the centripetal course of the wind in storms. By means of observers in different sections, he has been enabled to surround some of our great northern storms, and has satisfied himself that the same law uniformly prevails. We can only make a few selections from the great number which we find recorded in the volume before us.

The following diagram represents a destructive storm which swept along our southern coast in the middle of August, 1837. The facts respecting it were collected by Col. Reid, but Mr. Espy finds that they maintain his own views, although recorded by an advocate of the whirlwind theory. The map represents the position of the storm as it was at noon, on the 18th of August, and the arrows are intended to show the direction of the wind at that time.

Mr. Espy observes: "I have culled out of this storm, that portion of time in which I find the greatest number of simultaneous observations, and I have exhibited on the annexed wood-cut the localities of all the ships within the boundaries of the storm, whose latitudes and longitudes could be ascertained with any degree of certainty, with arrows, exhibiting the