Studies concerning the Relation between the Activity of the Sun and of the Earths Magnetism.no. Ii

,4bstract.--This article is a continuation of the previous one by the authors on the same subject. With the aid of additional data, •t is once more found that the quantities a and b in the formula Q=aq-b $ vary with sunspot activity, and apparently also with time; Q is the measure of magnetic activity, and S that of solar activity. The parameter a varies directly, and b inversely with sunspot activity. The measure of magnetic activity, Q, is evidently subject to the same periodicities as found by various authors from analyses of the sunspot numbers. Thus an analysis of concomitant magnetic and sunspot data for the period 1841 to 1910 made by G. N. Armstrong and C. R. Duoall at the Department of Terrestrial Magnetism, in the summer of 1914, indicated the existence of periods of about 11.4 years, 22 years, and a third in the neighborhood of 70 years.*