The meteorological investigations published in the early numbers of the Journal have played an important role in establishing a correct theory of storms. Before the origin of the United States Signal Service in 1871 no systematic weather reports were issued by any governmental agency in this country, and consequently the work of collecting as well as interpreting meteorological data rested entirely in the hands of interested individuals and institutions. The earliest important studies of storms to appear in the Journal were contributed by Redfield of New York, whose first paper (20, 17, 1831) treated in considerable detail a violent storm which passed over Long Island, Connecticut and Massachusetts in 1821. He concluded that “the direction of the wind at a particular place, forms no part of the essential character of a storm, but is only incidental to that particular portion ... of the track of the storm which may chance to become the point of observation, ... the direction of the wind being, in all cases, compounded of both the rotative and progressive velocities of the storm.” A few years later, analyses of twelve “gales and hurricanes of the Western Atlantic” (31, 115, 1837) led to the statement that the phenomena involved “are to be ascribed mainly to the mechanical gravitation of the atmosphere, as connected with the rotative and orbital movements of the earth’s surface.” In this paper is emphasized the fact that the wind may blow in diametrically opposite directions at points near the storm center. “While one vessel has been lying-to in a heavy gale of wind, another, not more than thirty leagues distant, has at the very same time been in another gale equally heavy, and lying-to with the wind in quite an opposite direction.” From an accompanying sketch showing wind directions, the reader would infer that, at this time, Redfield believed the motion of the air to be very nearly in circles about the storm center. The same idea is conveyed by a later paper (42, 112, 1842). Espy (39, 120, 1840) of Philadelphia, however, claimed that observation showed rather that the wind blew inwards toward a central point, if the storm were round in shape, or toward a central line, if it were oblong. This view Redfield (42, 112, 1842) contested, and brought forth much evidence to prove its falsity. A later statement (1, 1, 1846) of his own theory is as follows: “I have never been able to conceive, that the wind in violent storms moves only in circles. On the contrary, a vortical movement ... appears to be an essential element of their violent and long-continued action, of their increased energy towards the center or axis, and of the accompanying rain.... The degree of vorticular inclination in violent storms must be subject, locally, to great variations; but it is not probable that, on an average of the different sides, it ever comes near to forty-five degrees from the tangent of a circle,—and that such average inclination ever exceeds two points of the compass, may well be doubted.” A qualitative explanation of the effect of the earth’s rotation on the direction of the wind near the storm center had already been given by Tracy (45, 65, 1843), and this was followed some years later by Ferrel’s (31, 27, 1861) very thorough quantitative investigation of the dynamics of the atmosphere.
A number of individuals kept systematic records of meteorological observations, among whom was Loomis, whose storm analyses did much to settle the merits of the rival theories of Redfield and Espy. In studying the storm of 1836 (40, 34, 1841) he had drawn on the map lines through those points in the track of the storm where the barometer, at any given hour, is lowest. While this method revealed the general direction in which the storm was progressing, it failed to give much indication of its size or shape. In discussing the two tornadoes of February, 1842, one of which had already been described in the Journal (43, 278, 1842), he adopted a new and more illuminating graphical method. Instead of connecting points of lowest pressure, he drew a curve through all points where the barometer stood at its normal level, then one through those points at which the pressure was ²⁄₁₀ of an inch below normal, and so on. Temperature he treated in much the same way, and the strength and direction of the wind were indicated by arrows. This innovation gave to his storm analyses a significance which had been entirely lacking in those of his predecessors, and led to the familiar systems of isobars and isotherms in use on the daily charts issued by the Weather Bureau at the present time. Loomis advocated careful observations for one year at stations 50 miles apart all over the United States, so that sufficient data might be obtained to settle once for all the law of storms. His efforts, seconded by those of Henry, Bache, Pierce, Abbe, and Lapham, led eventually to the establishment of the Signal Service, and the publication of daily weather maps according to the plan advocated thirty years before. These maps afforded a basis for further analyses of storms, which he published in numerous “Contributions to Meteorology” (8, 1, 1874, et seq.) between 1874 and his death in 1890.
In addition to his work on storms, Loomis made a careful study of the earth’s magnetism (34, 290, 1838 et seq.), and of the aurora borealis (28, 385, 1859 et seq.). That a connection existed between sunspots, aurora, and terrestrial magnetism was already recognized. Loomis (50, 153, 1870 et seq.), however, showed that the periodicity of the aurora borealis, as well as of excessive disturbances in the earth’s magnetic field, corresponds very closely with that of sunspots.
Notes.
[154]. J. W. Gibbs, Trans. Conn. Acad. Arts and Sci., 3, 108 and 343. Abstract by the author, the Journal, 16, 441, 1878.
[155]. H. K. Onnes, Nature, 93, 481, 1914.
[156]. H. Hertz, Wied. Ann., 34, 551, 1888 et seq.
[157]. E. F. Nichols and G. F. Hull, Phys. Rev., 13, 307, 1901 et seq.
[158]. J. J. Thomson, Phil. Mag., 44, 293, 1897.
[159]. R. A. Millikan, Phys. Rev., 2, 109, 1913.