60 DR. FARADAY’S EXPERIMENTAL RESEARCHES IN ELECTRICITY. (SERIES XXVI.) 
sun is slowly withdrawn, and then again slowly renewed during the remaining part 
of his journey, exception being made for the present of the paramagnetic effects due 
to cold. 
2905. I will now consider the Toronto case of diurnal variation as it is presented 
to us in the volume of magnetical observations, issuing from the same authority and 
hands as the former volume*, and also in further observations down to 1848, sent 
to me by the kindness of Colonel Sabine. The position of the observatory is in lat. 
43° 39' 35" N. and long. 79° 21' 30" W. The absolute declination is 1° 21' 3" W., and 
the mean or absolute dip is 75° 15' N., so that as regards Hobarton it is on the other 
side of the equator, and nearly on the other side of the world. The result for the 
months of June and December are placed in a diagram corresponding to that for 
Hobarton (2896.), employing the Toronto time for the hours, Plate I. fig. 12. 
2906. The north end of the needle is that universally referred to in speaking of the 
declination ; its course at Toronto, during the immediate sun effect, is as follows : — 
Having gradually moved east from Id'*, it is at extreme east at 20 o’clock, and then 
returns from the east to extreme west in six hours, after which it moves eastward 
from the sun. But if we convert this into the motion of the equatorial extremity of 
the needle, for that is the upper end if the needle be free, and concerns us most in 
the comparison with Hobarton, then it will be seen that this end is most west at 19*^ 
or 20*^ ; and leaving that position at that hour, it travels quickly eastward, passing 
through the full range of variation or to extreme east in six hours, or until 2^, and 
then returns, following the sun. 
2907. Looking at these results, I might repeat the words used in illustration of the 
Hobarton effects, but for the sake of brevity will simply refer to them. As before, 
the amount of variation in the declination is in summer double what it is in winter. 
The difference of temperature is three times greater. The extreme west and east 
declination is both in summer and winter at 20 and at 2 o’clock, so that the magnet 
holds to the time in both seasons; but the maxima and minima of cold, as shown 
before, vary in the two seasons, for the former is at 4 o’clock in summer and 2 in 
winter, whilst the latter is at 16 o’clock in summer, and 20 o’clock in winter. But 
this is a variation with consistency ; for it will be seen by a moment’s inspection, that 
in winter the maximum of heat has moved towards the time of most powerful action 
in the one direction, and the minimum has moved towards it in the other. The passage 
of the sun, therefore, over the meridian, and the period of rapid motion of the needle 
from west to east, still coincide. 
2908. The other element of direction is the inclination. Its variation is very small, 
but changes thus. A principal maximum dip occurs at 22 o’clock, and the extreme 
minimum dip at 4 o’clock. 
2909. So all the effects may again be generally represented by an ellipse (fig. 13) 
* Magnetical and Meteorological Observations. Toronto, 1840, 1841, 1842, Sabine. 
