6^O niKKKLAM). Mil: MIKWF.I.IAN ATROKA I'UI.ARls K.\ I'KDI'I IO.\ , 1 go2 1903. 



N. pule, corresponding to the S. pole of Farth magnetism. We find these belts of light sometimes a-; 

 here, with ;i tolerable, even strength of light like a continuous band, and at oilier times we find tin 

 ravs eoneeiitrated in three limited streaks, with well definable positions around the magnetic poles of 

 the terrella. 



"Figure 3 1 12081 also shows an equatorial ring. This phenomenon of light is magnificent, but un- 

 stable; it is difficult to produce; it may suddenly appear and suddenly vanish, as the rays which run 

 round the terrella at the equator are difficult to get sufficiently concentrated for the rarefied gas to illu- 

 minatel'l. At the lower part of Fig. 3 and on Fig. 4 (135!, a characteristic pointed tongue of light will 

 be seen, which is drawn in, and shows the manner in which the rays here come in to the terrella 

 The magnetic equator is drawn on the terrella with a dark line." 



(Fig. 200 tV 219 give a capital picture of these pointed tongues of light. In fig. 219, the two 

 tongues appear as one, the one being immediately over the other). 



"It may now be imagined, that analogous formations of light might be observable, around the Earth, 

 of the rays from the Comet's tail on the 1 8th 1 9th of May. The downward rays in the I'olar regions 

 will, it is true, be difficult to observe in northern parts, owing to the northern declination of the sun, 

 bill in antarctic regions there could be more hope of being able to do so, and the phenomenon would 

 then probably appear somewhat similar to the Aurora australis. At night, in low latitudes, one could 

 conceive the possibility of a ring like the equatorial ring being observable as a sort of zodiacal light. 



"About the 2nd of May, the comet will be in the vicinity of Venus (see Bulletin dc la Sociilr 

 . l^lroiiuinii/iie il/' I~ ranee, l^evner ign>, p. 57), and it is not impossible that indications of an alteration 

 in those parts of the Comet's tail nearest the Planet might be noticeable. 



"We may then possibly expect to find traces of the rays being drawn in towards the Polar 

 regions of Venus, ill a manner similar to thai demonstrated by the experiment shown in Fig. 4 (135!, 

 or a more or less distinct bending of the Comet's tail, assuming Venus to be magnetic. 



"The probability of such being visible must, however, be admitted to be .small, as the central line 

 of the tail, if il is directly away from the sun, will be at a considerable height above the Planel; but I 

 will nevertheless call the attention of Astronomers to these conditions, as Venus, if equally as strongly 

 magnetised as our Farth, must be expected to exercise a noticeable influence on the tail of the Comet 

 at a distance of several million kilometres, especially if the rays in the tail are easily deviated by mag- 

 netic force. 



"This phenomenon might, in case it were present, be determined by astronomical observations of 

 the Comet's tail and Venus in the period from i st to 3rd May and I beg therefore, dear Sir, respect- 

 fully to ask you, in the interests of science, il you would kindly have the necessary observations made, 

 il possible, and that yon would favour me with a short account of the results." 



1 he matter awakened interest in many quarters, and from Gottingen an expedition similar to mine 

 was sent to my former station at Oyrafjord in Iceland, under the direction of Dr. G. A.NGENHEISTER. 

 ISolh tin Norwegian and the German stations were chosen out of regard to the fact that experience had 

 been gained there from previous observations, especially of magnetic storms. 



In addition to magnetic rcgisterings, earth-current registerings were made and measurements taken 

 ol atmospheric electricity. Meteorological observations were also made. 



l>eiore entering upon a description of the experiments that were made, and discussing the results 

 that may apparently be deduced from the observations at the I laldde Observatory at Kaafjonl, I will 

 attempt to give an epitome of the astronomical and meteorological observations that I have succeeded 

 in collecting from various quarters of' the globe; for il is not from observations from one place that 



i 1 ) Sec Aitirle- i i [ and i 19. 



