TERRESTRIAL MAGNETISM. 81 



vations have been co-ordinated and published by Colonel 

 Sabine in the Phil. Trans, for 1843, Art. x., and for 1844, 

 Art. vii. ; and part yet remains to be published. 



1839 1851. Kreil's observations on the variations of 

 the three magnetic elements, continued for more than 

 twelve years at the Imperial Astronomical Observatory at 

 Prague, and published in annual volumes, with valuable 

 co-ordinations and discussions. 



1840. Hourly magnetic observations with a Gambey's 

 declination-needle, made during a ten years' sojourn in 

 Chili by Claudio Gay. (See his Historia fisica y politica 

 de Chile, 1847.) 



1840 1851. Lament, Director of the Astronomical 

 Observatory at Munich : Results of his magnetic obser- 

 vations compared with those of Gottingen, which go back 

 as far as 1835 : important law of a decennial period in the 

 diurnal variation of the declination. (Lamont, in Poggend. 

 Ann. der Phys. 1851, Bd. Ixxxiv. S. 572582; and Eels- 

 huber, 1852, Bd. Ixxxv. S. 179 184.) The already noticed 

 conjecture of a connection between the periodical magnetic 

 variations which follow laws depending upon solar hours 

 (magnetic storms and diurnal variation), and the periodical 

 " frequency of the solar spots," was first made by Col. Sabine, 

 in the Phil. Trans, for 1852 ; and four or five months later, 

 but without his having known of Colonel Sabine' s published 

 paper, by the learned Director of the Astronomical Obser- 

 vatory at Berne, Rudolph Wolf, in the Schriften der 

 schweizerischen Naturforscher.( 73 ) Lamont's Handbuch 

 des Erdmagnetismus (1848) contains an account of the 

 most recent German apparatus and methods of computing 

 the results of observation. 



VOL. IV. Q 



