562 Intelligence and Miscellaneous Articles. 



complete on those days on which the disturbances are not sudden. 

 Now it will be readily understood that in the former case the tran- 

 sitory currents in opposite directions which rapidly succeed each 

 other, will be partially destroyed by the magnetization of the earth, 

 so that the variations of the magnetic instruments will be relatively 

 smaller. The observations of the 15th November, 1882, and of 

 1st March, 1883, as well as the curves registered by the magneto- 

 graph, support this explanation. The curves registered on the 

 1st of March show by the clearness of the lines a relatively tranquil 

 course of the magnets, although the slow disturbances have been 

 somewhat large ; and, in consequence, the curves drawn from the 

 readings of the galvanometers are not very marked, and those of 

 the S.-N. current are very similar to the curves of the unitilar, 

 while those of the E.-W. current are in close agreement with the 

 registrations of the bifilar. On the other hand, the two kinds of 

 curves of November 15 show little agreement with each other ; 

 and although the variations of the two currents are very great and 

 very rapid, the registers of the magnetograph, as well as the direct 

 observations of the magnetic instruments, do not show great pertur- 

 bations ; but if we examine more closely the curves registered, we 

 easily observe the traces of a permanent oscillation of magnets 

 within small limits. 



We may then conclude that earth currents are always the primary 

 cause of magnetic storms^ but not of the periodical variations of the 

 magnetic elements. 



Observations on earth currents in the telegraph lines of Austria, 

 which Director Midler of Pola has kindly communicated to me, 

 show that in long lines also the earth current is seen in the same 

 way as in our very short lines — that is to say, a a rapid series of 

 alternating currents. It follows from this, that earth currents at 

 the time of magnetic storms are usually currents of induction and 

 discharge ; this is entirely in harmony with the connexion between 

 these storms and aurorae boreales, w 7 hich the experiments of M. 

 Lemstrom entitle us to consider as discharges of atmospheric and 

 terrestrial electricity. 



Unfortunately the observations of earth currents in some of the 

 longer Russian telegraph lines, which were projected for the epoch 

 of the Pclar expeditions, have not been made. It was therefore 

 not possible for me to compare the observations of our short lines 

 with those of the longer ones starting from the same point, so as 

 to learn how far the currents of the two kinds of lines are in 

 agreement. But as in any case the telegraph lines could only have 

 been at our disposal for a short time, and as there are as yet no 

 underground lines in Russia, I think for the present it would be 

 more useful for such comparisons to have at our disposal lines in 

 all respects similar to those a kilometre long which we already have, 

 but five to ten times as long. — Bulletin de VAcademie des Sciences 

 de St. Petersbourg, December 11, 1883. 



