Online Encyclopedia
Search over 40,000 articles from the original, classic Encyclopedia Britannica, 11th Edition.
XXXVI
Online EncyclopediaEncyclopedia Home :: WIL-YAK
del.icio.us it!
|
XXXVI . contains See also:separate data for the 14 years of that See also:period which represented the highest See also:sun-spot frequency, and the 15 years which represented lowest sun-spot frequency. It will be seen that relatively considered the seasonal frequencies of disturbance are more nearly equal in the years of many than in those of few sun-spots. Storms are more numerous as a whole in the years of many sun-spots, and this preponderance is especially true of storms of the largest See also:size. This requires to be See also:borne in mind in any comparisons between larger and smaller storms selected promiscuously from a See also:long period. Ansunduly large proportion of the larger storms will probably come from years of large sun-spot frequency, and there is thus a See also:risk of assigning to See also:differences between the See also:laws obeyed by large and small storms phenomena that are due in whole or in See also:part to differences between the laws followed in years of many and of few sun-spots. The last data in Table XXXVI. are based on See also:statistics for See also:Batavia given by W. See also:van Bemmelen," who considers separately the storms which commence suddenly and those which do not. These sudden movements are recorded over large areas, sometimes probably all over the See also:earth, if not absolutely simultaneously, at least too nearly so for differences in the See also:time of occurrence to be shown by See also:ordinary magnetographs. It is ordinarily supposed that these sudden movements, and the storms to which they serve as precursors, arise from some source extraneous to the earth, and that the commencement of the See also:movement intimates the arrival, probably in the upper See also:atmosphere, of some See also:form of See also:energy transmitted through space. In the storms which commence gradually the existence of a source See also:external to the earth is not so prominently suggested, and it has been some-times supposed that there is a fundamental difference between the two classes of storms. Table XXXVI. shows, however, no certain difference in the See also:annual variation at Batavia. At the same time, this possesses much less significance than it would have if Batavia were a station like See also:Greenwich, where the annual variation in magnetic storms is conspicuous. Besides the annual period, there seems to be also a well-marked diurnal period in magnetic disturbances. Additional information and CommentsThere are no comments yet for this article.
» Add information or comments to this article.
Please link directly to this article:
Highlight the code below, right click, and select "copy." Then paste it into your website, email, or other HTML. Site content, images, and layout Copyright © 2006 - Net Industries, worldwide. |
|
|
[back] XXXV |
[next] XXXVII |