Three theories have been advanced by meteorologists of this country, two of which profess to explain all the phenomena of the weather. Professor Espy attributed the production of storms and rain to an ascending column of air, rarefied by heat, and the rarefaction increased by the latent heat of vapor given out during condensation, and an inward tendency of the air, from all directions, toward the ascending vortex, constituting the prevailing winds. Thus, Professor Espy conceived, and to some extent proved, that the wind blew inward, from all sides, toward the center of a storm, either as a circle, or having a long central line, and he conceived that it ascended in the middle, and spread out above; and that clouds, rain, hail, and snow, were formed by condensation consequent upon the expansion and cooling of the atmosphere, as it attained an increased elevation.
This ascent was not, in fact, proved by Professor Espy, has not been found by others, and is not discoverable, according to my observations. The theory was ingenious, founded on the theory of Dalton, that the vapor was maintained in the atmosphere by reason of a large quantity of latent heat, which was given out when condensation took place. This theory is also unsound. No such elevation of temperature is found in clouds or fogs when they form near the earth, however dense. Thus the two principal elements of Professor Espy’s theory are found to be untrue, and the theory untenable. But it was sustained with great ability and research, and the distinguished theorist deserves much for the discovery and record of important facts in relation to the weather. Aside from its theoretical views, his book contains a great mass of valuable information, and will well repay the cost of purchase and perusal.
Another theory, by Mr. Bassnett, is of recent date, founded on the influence of the moon, and the supposed creation of vortices in the ether above, whose influence extends to the earth, producing storms and other phenomena. No one can peruse his book without conceding to him great ability and scientific attainment; and if his theory was true, the periods of fair and foul weather could be calculated with great mathematical certainty. But it contains inherent and insuperable objections. I will only add that all herein before contained is in direct opposition to it.
Mr. W. C. Redfield, of New York, as early as 1831, first advanced in this country the theory of gyration in storms, and investigated their lines of progress on our coast and continent. His theory is limited in its character, and does not profess, except indirectly, to explain all, or indeed any, of the other phenomena of the weather. As far as it goes, however, it is generally received in this country and Europe, and has been adopted by Reed, Piddington, and others, who have written on the law of storms. The position of Mr. Redfield is honorable to himself and his country. Science and navigation are much indebted to him for his industry in the collection of facts. Nevertheless, his theory is not in accordance with my observation, and I deem it unsound. Although expressed disbelief of the theory has been characterized as an “attack” upon its author, I propose, with that respect which is due to him, but with that freedom and independence which a search for truth warrants, to examine it with some particularity. It is a part of the subject, and I can not avoid it.
When the theory was first announced, I adopted it as probably true; and being then engaged in a different profession, which took me much into the open air by night and day, I watched with renewed care the clouds and currents for evidence to confirm it. I discovered none; on the contrary, I found much, very much, absolutely and utterly inconsistent with its truth. The substance only of these observations will be adduced.
Mr. Redfield admits that the progression of our storms in the vicinity of New York, is from some point between S. S. W. and W. S. W., to some point between N. N. E. and E. N. E. According to my observation, except perhaps in occasional autumnal gales, they are not often, if ever, from S. of S. W., and the great majority of them, including, I believe, all N. E. storms, are between S. W. and W. S. W. Now, the card of Mr. Redfield, moving over any place from any point between S. W. and W. S. W., calls for a S. E. wind at its axis, an E. wind at its north front, and a S. wind at its south front, and does not call for a N. E. wind on its front at all, except at the north extreme, where it could not continue for any considerable period.
Fig. 17.
In relation to this, I observe, 1st. About one-half of our N. E. storms, including some of the most severe ones, not only set in N. E., but continue in that quarter without veering at all, during the entire period that the storm cloud is over us; usually for twenty-four hours; not unfrequently for forty-eight hours, sometimes for seventy-two or more hours. This every one can observe for himself, and it can not, of course, be reconciled with his theory.
2d. N. E. storms, whether they set in from that quarter in the commencement, or veer to it afterward, when they do “change” round, more frequently veer by the S. to the S. W. in clearing off, than back through the N. into the N. W. The former, in accordance with his theory, they can not do, as the reader can see by passing the left side of the card over his place of residence on the map from S. W. to N. E.