( 778 ) 



Date Europe N. -America 



LH LD LB L D 



May 18'i' 1892 +/_ wjE -/+ elW 



July IG^'i ,, — /i" and IF are missing 



Aug. J2''' „ - ^andir + E'mhWV 



„ 18^1' 1893 + e/W are missing 



Sept. 25t'' „ + W „ „ 



Jan. 2"d 1894 + tv/E — /+ ^yiF (only San Antonio) 



Febr. 20^'^ „ -/+ w/L -/+ iv/E 



July 2011' „ -h e/W + e/W 



Aug. 20^'^ „ + e/W + iv/E 



Nov. 13^'' „ -/+ e/W +/_ w/E 



Aug. 16ti> 1902 + e/W + ?ü/j^ 



April 5"' 1903 + e/W -/+ ?ü/^ 



Febr. 3'^' 1905 + e/W + w/E 



We see here repeatedly that the European group and the American 

 one are the i-everse of each other, and in Europe we find mostly a 

 iV^.ir. vector, in x4.merica a N.E. one, which points to a centre of 

 disturbance near Greenland, thus situated near the magnetic pole and 

 that of the Aurora-Borealis or pole of disturbance. 



For some cases I have tried to obtain a sur\ey by means of a 

 map with the simultaneous vectors of disturbance, but here the 

 almost insurmountable difficulty presents it.self, that one cannot 

 make up simultaneous values of A H and A D, which are really 

 trustworthy. Above I pointed to the fact with reference to the 

 measurements on the Buitenzorg magnetograms, that this requires an 

 ample and trustworthy time-measurement. Tiiough it was impossible 

 for me to calculate exact values for the azimuth of those vectors, 

 yet I could about fairly well find the direction. 



For the initial movement of the disturbance on Febr. 3'^ 1905 the 

 vectors of the introductory movement pointed to a centre at the 

 West coast of North America and that of the main movement to a 

 centre near Greeidand. For the disturbances on Aug. 16''' , 1902 and 

 April 5*1', 1903 I found about the same'). 



Vertical force. 



It is a striking fact, that places lying at a slight distance from 

 each other show an opposite change in the vertical component. Above 



1) Writing this 1 see from a paper by Dr. Brïjckmann (Meteor. Zeitschrift, 

 1907, No. 12) on the same subject, tliat Ijc also arrives at a centre of disturbance 

 appearing in the vicinity of the magnetic pole. 



