104 DR. FARADAY’S EXPERIMENTAL RESEARCHES IN ELECTRICITY. (SERIES XXVII.) 
as these and the deelination variations should be closely considered and compared 
together at every hour for each particular place. The inclination variation at 
Hobarton is greatest in its summer, being then 2'T8, and least in winter, or 1'‘28, as 
was to be expected. The great variation occurs in the daytime, as with the deelina- 
tion ; the dip being most as the sun region passes over the meridian. The greatest 
dip is not at the same hour for all the months ; it occurs at 23 o’clock for December, 
February and March, at 24 o’clock for September, at 1 o’clock for June and July; 
as it moves on so do the points of least dip on each side of it, so that the whole 
curve advances in time in the order of these months. There is also another affection 
of it, for the quickest transition is from most to least dip in some months, as December, 
February, and from least to most dip in other months, as June, July, September. At 
Toronto the dip variation, though peculiar in some points, may be said to have the 
same general character. 
3029. For the variation of the total force at both places, I will at present only 
refer to Colonel Sabine’s volumes, and the observations he has made thereon. 
3030. There is a remarkable difference between the time of the day changes at 
Hobarton and Toronto, to which Colonel Sabine has called attention. It consists in 
the occurrence of those at the latter place, about an hour before those of the former. 
If this had depended upon the declination, then the change should have taken place 
first at Hobarton, for there the sun arrives at the magnetic meridian before he comes 
to the astronomical meridian, and for like hours of local time he is in a better 
position in the quadrant in the afternoon than at Toronto ; still it is the later of the 
two. 
3031 . If the time of the sun-swing from west to east be considered, the middle of it 
ought to be somewhere near the period wlien the warm region is passing the magnetic 
meridian (2982.), and in that way supplies an approximative expression of the relative 
positions of the region and the sun. The swing is at Hobarton from 21 to 2 o’clock, 
or five hours, and the magnetic meridian is passed by the sun nearly in the middle 
of the time, or 23^' 20' o’clock. But according to the supposition just made, this is 
also the time at which the warm region ought also to pass, and so the sun and the 
region in this place appear to arrive at the meridian together. At Toronto the sun- 
swing is about four hours in winter, or from 21 to 1 o’clock, and five hours in 
summer, or from 20 to 1 o’clock. Of the latter five hours the middle is 22^ o’clock, 
at which time the region ought to pass over the magnetic meridian, and as tliat coin- 
cides nearly with the astronomical meridian, it appears that the region is about 1^ 
hour before the sun. By a similar comparison for winter, the region would then 
appear to be about an hour before the sun*. 
* In reference to the position in advance of the sun, of the resultant of those actions which set the needle 
end westward, we must remember that the preceding cold, being perhaps seven hours only to the west, is by its 
action on the general system of the curves aiding the westening of the needle, whilst the sun is in the east 
and even over the meridian (3005.). 
