106 DR. FARADAY’S EXPERIMENTAL RESEARCHES IN ELECTRICITY. (SERIES XXVII.) 
because of the great declination, the sun is in the astronomical meridian two hours 
before he arrives at the magnetic meridian in Cape winter, and half an hour or more 
before in Cape summer. 
3036. The sun passes obliquely through both the chief quadrants and across their 
central parts pretty equably; but because of the western character of the mean de- 
clination he is much nearer the Cape when in the eastern than when in the western 
quadrant for all the months, and so the coming* up effect, i. e. the westening before 
the midday swing commences, ought to be more powerful than the eastening after it 
is over, and such is the case. This is in beautiful and striking contrast to Green- 
v/ich, which, having the same kind of mean declination and nearly in the same de- 
gree, is on the north of the sun’s path, and therefore the luminary passes its mag- 
netic meridian before 12 o’clock, and for a time still approaches the station; the re- 
sult is the reverse effect to what we have at the Cape ; for the eastening effect at the 
end of the midday swing is more powerful than the westening effect before it, as is 
well seen by the curves given in Plate II. 
3037. Selecting July as the month in which the effect of winter occurs at the Cape, 
we find that the day-swing is very feeble, as it ought to be, the sun being in the 
northern tropic and far away ; and the swing east is at an end by 3 o’clock, when the 
sun has passed by about one hour over the magnetic meridian. The upper or north 
end of the needle then westens for two hours, following the sun until 5^, when the 
luminary is low to the Cape and at its setting. After that the needle end eastens 
slowly until 10’’, then a little more quickly until midnight (passing the mean position 
at 11'’) ; quicker still until 16'’ or 17^ and still more quickly until 19'’, when it has 
attained its maximum east position. This effect I believe to be due to the cold, which 
in these hours is approaching from the east, and setting by its paramagnetic action 
(3003.) the needle end eastward. On the surface of the earth the maximum cold in this 
month is at 17'* or 18'*, and as far as it goes this result accords with the effect above 
described. At 19'*, the sun in rising not only stops the eastening but quickly drives the 
needle back again, and the latter very rapidly goes westward until about 23'*, at 
which time the sun-swing from west to east comes on, being over by 2'’ or 3'’, com- 
pleting the daily variation, after which the needle goes west, following the sun as be- 
fore. In this sun-swing is seen the effect of an inclined magnetic meridian (3000.) ; 
for though the sun is, at the beginning, only an hour east of the astronomical meridian, 
he is full three hours to the east of the magnetic meridian. As the swing occupies 
about four hours, the warm region is probably near the magnetic meridian about 
half-past 12 or 1 o’clock. 
3038. January presents a case of Cape summer. The day-swing is then from 
21'’ to l'’ or 2'’. After 2'’ the needle upper end follows the sun westward until 6'’, and 
then moves a little eastward for two hours ; after this it moves slowly westward 
again, the whole effect being as if a cold region had occurred on the east, had passed 
over and gone away west, and the temperature below at this time is within 2° of the 
