PART III. EARTH CURRENTS AND EARTH MAGNETISM. CHAP. 1. 727 



His results were in short the following: 



(1) He thinks that on repeatedly examining the agreements of the two systems of curves it is im- 

 possible to avoid the conclusions that the magnetic disturbances are produced by terrestrial 

 galvanic currents below the magnets. There still remain some points to be explained before 

 we can prove that galvanic currents, as we observe them, will account for all that we observe 

 in magnetometer records^). 



(2) Regarding the total magnetism he says: 



"On one point we can speak with confidence; they do not explain the existence of the 

 principal part of terrestrial magnetism" ( 2 ). 



(3) The general agreement of curves, especially in the bold inequalities, is very striking particularly 

 in the curves relating to northerly force ( 3 ). 



(4) The small irregularities in the curves of galvanic origin are more numerous than those in the 

 curves of magnetic origin ( 3 ). 



(5) The irregularities in the curves of galvanic origin usually precede, in time, those of magnetic 

 origin, especially as regards westerly force ( 3 ). 



(6) The proportions of the magnitudes of rise and fall in the curves often differ sensibly, especially 

 as regards westerly force ( 4 ). 



(7) The northerly force appears, on these days of magnetic storms, to be increased, whereas 

 general experience leads us to expect that it would be diminished( 4 ). 



(8) In agreement with Walker he finds that the earth-currents observed on calm days are real earth- 

 currents, and finds that they show a well-marked diurnal period; but he says that neither in 

 magnitude nor in law are these inequalities, consequent on galvanic currents, competent to 

 explain the ordinary diurnal inequalities of magnetism ( 5 ). 



(9) At present we are unable to say whether the records of the galvanic currents throw any light 

 on the origin of the diurnal variations of the magnetic elements ('''). 



The next great step in earth-current research was inaugurated by the Electrical Congress at Paris 

 i 1881. It was decided that earth-current observations ought to be carried out simultaneously in as 

 lany countries as possible. Partly as a result of the work of the committee, partly in connection with 

 ie international polar expeditions of 1882 83, a great amount of work was next done to investigate 

 ie laws of terrestrial currents. 



In France registerings were undertaken by BLAViER( 7 ), in England at the Greenwich Observatory ( 8 ), 

 i Russia by H. WILD("), in Finland by LEMSTROM) 10 ), in Italy by BATELLif 11 ), in Bulgaria by BACHMETJEW( I:! ), 

 t Kingua Fjord near the auroral zone by GIESE( IS ), and in India by E. O. WALKER ( 14 ). 



(') loc. cit , 1868, p. 471. 



(-> 1868, p. 472. 



( :l l 1870, p. ai6. 



( 4 ) a 1870, p. 216. 



( J ) 1870, p. 226. 



() 1868, p. 472. 



(") E. BLAVIER: Etudes des Courants Telluriques, 1884. 



( 8 ) Greenwich Magnetical and Meteorological Observations, 1882 and 1883. 



l") H. WILD: Beobachtungen der elektrischen StrGme der Erde in kilrzern Linien. Mem. Acad. Imp. Sci. St. Petersburg, 



1883. 



( 10 ) Expedition Polaire Finlandaise: 188283 et 188384. 



( n ) A. BATELLI : Sulli correnti telluriche. Atti R. Acad. Lincei 1888. 



( 12 ) BACHMETJEW: Der gegenwartige Stand der Frage fiber elektrische ErdstrOme. Mem. Acad. Imp. Sci. St. Petersburg. 



f' -l Beobachtungsergebnisse der deutschen Stationen, 1882 83, I, p. 411. 



( 14 ) F.. O. WALKER: Earth-currents in India, Journal Soc. Tel. Eng. Xll, 1883; XVII, 1888; XXII, 1893. 



