TERUESTUIAL MAGNETISM. 14-1 



were most frequent at Toronto in the northern hemisphere 

 were also those in which they were most numerous at 

 Hobarton in the southern hemisphere, and that nearly in 

 an equal degree. In regard to the differences in different parts 

 of the year, the disturbances were, on the whole, twice as 

 numerous at Toronto in the summer months of the station 

 (April to September), as in its winter months (October to 

 March). (In my Berlin observations of 1806 the greatest 

 number in any month belonged to the month of September 

 at the time of the autumnal equinox.) ( 176 ) They are more 

 rare in the winter months of each station ; i. e, more rare from 

 November to February at Toronto, and from May to August 

 at Hobarton. The times of the Sun's passage over the equator 

 are also, according to Captain Younghusband, in a high degree 

 remarkable for the greater frequency of disturbances at St. 

 Helena and the Cape of Good Hope. In the higher latitudes 

 of both hemispheres the disturbances are less frequent in the 

 winter than in the summer, i.e. less frequent at Hobarton from 

 May to September, and at Toronto from November to March. 

 A most important feature in the phenomenon also first 

 made known by Sabine, is the regularity, in both hemi- 

 spheres, of the disturbances in the direction of the needle 

 either to the east or to the west. At Toronto, where there 

 was a small west declination (1 33'), the number of distur- 

 bances which deflected the needle to the east preponderated 

 in summer (June to September), and that of those which 

 deflected it to the west, in winter (December to April) ; 

 and this in no inconsiderable ratio 411 : 290. The case 

 is similar at Hobarton, according to the seasons of the 

 southern hemisphere. In the winter months of that station 

 (May to August) the disturbances are strikingly less fre- 



