climatic changes which now take place in sunspot cycles. The past and the present are apparently a unit except as to the intensity of the changes. FOOTNOTES: [Footnote 31: O. Pettersson: The connection between hydrographical and meteorological phenomena; Quarterly Journal of the Royal Meteorological Society, Vol. 38, pp. 174-175.] [Footnote 32: A. Norlind: Einige Bemerkungen ueber das Klima der historischen Zeit nebst einem Verzeichnis mittelaltlicher Witterungs erscheinungen; Lunds Univ. Arsskrift, N. F., Vol. 10, 1914, 53 pp.] [Footnote 33: Thorwald Rogers: A History of Agriculture and Prices in England.] [Footnote 34: E. Brueckner: Klimaschwankungen seit 1700, Vienna, 1891.] [Footnote 35: For a full discussion of the changes in the Caspian Sea, see The Pulse of Asia, pp. 329-358.] [Footnote 36: S. Q. Morley: The Inscriptions at Copan; Carnegie Inst. of Wash., No. 219, 1920. Ellsworth Huntington: The Red Man's Continent, 1919.] [Footnote 37: See summary of Wolf's work with additional information by H. Fritz; Zuerich Vierteljahrschrift, Vol. 38, 1893, pp. 77-107.] CHAPTER VII GLACIATION ACCORDING TO THE SOLAR-CYCLONIC HYPOTHESIS[38] The remarkable phenomena of glacial periods afford perhaps the best available test to which any climatic hypothesis can be subjected. In this chapter and the two that follow, we shall apply this test. Since much more is known about the recent Great Ice Age, or Pleistocene glaciation, than about the more ancient glaciations, the problems of the Pleistocene will receive especial attention. In the present chapter the oncoming of glaciation and the subsequent disappearance of the ice will be outlined in the light of what would be expected according to the solar-cyclonic hypothesis. Then in the next chapter several problems of especial climatic significance will be considered, such as the localization of ice sheets, the succession of severe glacial and mild inter-glacial epochs, the sudden commencement of glaciation and the peculiar variations in the height of the snow line. Other topics to be considered are the occurrence of pluvial or rainy climates in non-glaciated regions, and glaciation near sea level in subtropical latitudes during the Permian and Proterozoic. Then in Chapter IX we shall consider the development and distribution of the remarkable deposits of wind-blown material known as loess. Facts not considered at the time of framing an hypothesis are especially significant in testing it. In this particular case, the cyclonic hypothesis was framed to explain the historic changes of climate revealed by a study of ruins, tree rings, and the terraces of streams and lakes, without special thought of glaciation or other geologic changes. Indeed, the hypothesis had reached nearly its present form before much attention was given to geological phases of the problem. Nevertheless, it appears to meet even this severe test.