348 CARNEGIE INSTITUTION OF WASHINGTON. 



the United States, as based on the Coast and Geodetic Survey magnetic 

 charts for 1905 and 1915. The general magnitude of the values of the Une 

 integrals is such that about 2 to 3 per cent of the Earth's total magnetic 

 field may have to be accounted for by a system of vertical currents. (See also 

 page 314.) 



The system of vertical currents, found from the preUminary computations, 

 was such that we apparently have, on the average, negative electricity 

 streaming into the Earth in polar regions, or regions of pronounced polar 

 lights, and streaming out into the air in lower latitudes. Or, we may say also 

 that we apparently have on the average, negative electricity streaming into 

 the Earth in polar regions, and positive electricity streaming into the Earth in 

 lower latitudes. The average resultant current-density for the region of the 

 Earth between the parallels 50° north and 50° south was found to be about 

 jV of an ampere per square kilometer; from previous investigations the 

 author had found a resultant current-density of about ^V of an ampere per 

 square kilometer. These quantities are about 10,000 times that of the cur- 

 rent-density of the vertical conduction-current deduced from atmospheric- 

 electric observations. 



Certain qualitative relationships were found to exist between the vertical 

 currents as disclosed by magnetic observations and those obtained from 

 atmospheric-electric observations, but quantitatively, the results from these 

 two sets of observations differ greatly. The results and possible explanations 

 are briefly discussed in the author's next paper, abstracted below. 



Measures of the electric and magnetic activity of the Sun and the Earth, and interrelations.^ 

 Louis A. Bauer. Terr. Mag., vol. 26, 33-68 (March and June 1921). 



Evidences of the existence of vertical electric currents, which form an 

 appreciable part of the Earth's permanent magnetic field and its variations, 

 have been multiplying since the publication of the author's paper,^ "On 

 vertical-electric currents and the relation between terrestrial magnetism 

 and atmospheric electricity." It would seem that several of the perplexing 

 phenomena of atmospheric electricity, e. g., the pronounced geographic varia- 

 tions and peculiar annual variation in the normal potential-gradient and 

 corresponding vertical conduction-current, and the maintenance of the 

 Earth's supposed negative charge, may find their readiest explanation in a 

 system of vertical currents distributed over the Earth in much the same 

 manner as are the currents which result from line integrals of the magnetic 

 force, or of its variations, taken around closed circuits on the Earth's surface. 



The paper is divided into the following heads: I, General considerations and 

 remarks; II, Measure of the Sun's activity; III, Measure of the Earth's 

 magnetic activity; and IV, Relations between solar activity and the Earth's 

 magnetic and electric activity. In No. I a general statement of the various 

 problems is made and tentative hypotheses, to be subjected to tests, are ad- 

 vanced in explanation of some of the Earth's magnetic and electric phenomena. 

 The chief results obtained with the aid of the measures derived in sections 

 Nos. II and III are summarized in No. IV and various graphs are given. (See 

 also abstract, p. 350.) 



^Abstract of the following papers: On measures of the Earth's magnetic and electric activity 

 and correlations with solar activity, presented before the Section of Terrestrial Magnetism and 

 Electricity of the American Geophysical Union, at the annual meeting, Washington, D. C, 

 April 18, 1921; Further investigations concerning the relations between terrestrial magnetism, 

 terrestrial electricity, and solar activity, presented at the general meeting of the American 

 Philosophical Society, Philadelphia, April 23, 1921; New relations between terrestrial mag- 

 netism, terrestrial electricity, and solar activity, presented before the Philosophical Society 

 of Washington, May 21, 1921. 



*See abstract, pp. 347-348. 



