202 W. A. Norton on the Variations of the Declination 
of the declination at the several hours from the means for the 
year at the same hours. An ordinate lying above m m shows 
that the needle is at that hour to the east of its mean annual po- 
sition at that hour, and an ordinate lying below mm shows that 
the needle is to the west of its mean position. 
ie 
17h 18h 19h 20h 21h 22h 23h Oh lh} 2h 3h 4h 
LAX 
ZU | 
moa SAL le 
ice v ae 
Re A 
17h 18h 19h 20h 21h 22h 23h Oh 2h Sh 4h 
1, Aug. 16 to 31; 2, Sept.1t015; 8, Oct.1 t0 15; 4, Oct. 16 to 31. 
The ecliptic currents play an important part in modifying the 
diurnal variations. Let us first see what should be their effects in 
the northern hemisphere at the time of the swammer solstice. If we 
follow the solstitial colure to the point 234° beyond the pole, we 
reach the last point excited ; this will move from east to west along 
the polar circle. I find that about 13 hours before 6 a. m. the current 
from this point will pass through the zenith of Toronto, crossing 
the meridian under an angle of 34°. At midnight it will cross 
the meridian perpendicularly, 233° south of the pole. Soon af- 
ter midnight the currents from the various points of the are con- 
necting the point in question with the pole, cross the meridian Un- 
der a very large angle and far to the north, and they should have 
but little effect ; but as their angle of inclination to the meridian 
decreases there will be a tendency to an easterly displacement, 
-which will go on increasing up to the hourof 45 20™ a. m. The 
points of meridian passage of the currents in qnestion will now, 
some of them fall to the south of the zenith, until finally at 6 4. ™ 
these currents will all pass through the point of intersection of the 
meridian and equator; which is now the pole of the solstitial 
colure. Between 4: 20™ and 6 a. m. their obliquity will be m- 
creased, their meridional components will be augmented, and the 
easterly motion should continue. The amount of the movement 
should be somewhat diminished by the southerly progressiol 
the points of meridian passage of the currents. ‘To consider DoW 
the effect of the remaining currents ; it suffices to investigate = 
tion of the currents of the northern hemisphere, since those of 
* : f be 
