208 W. A. Norton on the Variations of the Declination 
If we make a comparison between the hourly variations at 
vt equinoxes, toward the middle of the day, similar differences 
ught to obtai We have, therefore, an inequality of hourly 
kez of declination, which has its maximum positive value at the 
autumnal and its maximum negative value at the vernal equinox. 
At the summer solstice all the ecliptic currents tend to deflect the 
needle in the same direction, as they shift their position at a given 
hour ; and in the forenoon they have the same tendency as the ra- 
dial currents, in the afternoon the opposite tendency. Taking the 
numbers given for June (‘Table II.) we have r+ y=12"34, r—y= 
6-11, c=9/-22, and y=3"12. «& represents the effect of the radial 
currents and y the effect of the ecliptic currents from 7 a. M. to 
1 p.m, and also from 1 p.m. to7 p.m. If we compare 6 4. M. 
to 12m. with 12m. to 6 Pp. m. we have 2 =7'02, y=2'-94. 
The ecliptic cnrrents will have some effect in modifying the 
reed variations of declination, but we will not enter upon the 
study of their more minute effects on the present occasion, ‘The 
fiend table contains the mean hourly variations of the declin- 
ation for certain hours of the day for a period of six years, from 
1842 to 1848, which is half a solar period. 
TABLE II. 
Mean hourly variations ‘of the Declination at Toronto during a period of sit sae , 
From July, 1842, to June, 1848, inclusive. 
Jan. | Feb. |Mreh.| April | May.'June.| July.| Aug.| Sept | Oct. Nov. ] Bes 
ETE |e) eB |e |B | &. | W.. W.| W.| 
17. to 181. 0:06] 0°00} 0°54] 0-94! 1:53} 2°31) 2-01] 2°64) 1:28, 0°29 0°02 0-05 
Bat BAe | EB ete. LE eh Pe 
18. to 192, 0°56} 0°42) 0°94) 0.44! 0°97! 1-00! 1-47] 1 68! 1-25) 0°51 0°60) 0°28) 
. a ) E..| ©. | W.| E. | w.| W.L EB | Be 
19n. to 20n. 1:04] 0°54] 1-12] 0°15) 0-03) 0-251 0-19] 0-06) 0-94| 0°98 0°75) 0°31 
. | w.| wW.l ww. | w w.| w.| w.; W.| E 
20x. to 21n, 0°42] 0°84! 0°02} 1-00) 1°83) 1:55 1-70| 2°30] 1:66] 0°18 0°16) 0°61 
WwW. | W.| Ww. | Ww.) Welw 7. w. | w.| we, W. | W. 
Q1a. to 22a. 1:11 1°15} 205} 2°18] 8 28} 2°87) 2-85| 4-03] 3-25) 168 1°52) 0°66 
Ww WwW. | WwW. | Wo] OW. v.| Ww. | w.| W.| W. 
22n. to 234 1:76] 1°98] 2-93] 3-05! 3°40) 3-68] 3-38) 3-49] 2-99] 267 221) 1°68 
Ww W.'| Ww. | W./ Ww. w. | w. ; w.| W 
23n. to Or. 9-16] 1°50] 2°74 2-48) 2°18] 2°67] 2-74| 2-98) 1-92) 200 1°67) 1°66 
Ww W.|w.|wW.|w.!|w.|w.| BB | w.| WwW.) Ww 
Or. to In. 0°87] 0-23) 1:43) 1°23) 0-86) 1-37) 1-42) 0-98) 0°21) 0°43 0°76) 0°96 
Ww. Ww Eom | ERS oWs oe ME eee 8 
lk. to 2a. 0:06] 0-00! 0-01] 0-06) 0:29) 0-02! 0:12) 0°68) 0-83] 0°24 0°29) 0°01 
E|Bkl&£|E)e;E| Ss BE | 8 | BE | ©. 
Qh. to Ba. 0°59} 0°84! 0°67| 0°86) 1°10} 0-92! 0-84! 1°82/ 1°82/ 1°06 1°11) 0% 
E. BE. | 5 BE. | E Ee. | |) al ee 
3h. to 4h. 0°91) 0 86] 1:11] 1°66 1°71) 1-59) 1°29} 1°86] 1:79) 0:94 0°73) 0°95) 
BI B28 BE. EB : i 
4n. to Bn. 9°84) 0°46) 1:10) 1°53). 1°70} 1-82) 1 
se, a ae ja ae 
_ Br. to 6h, 061 one 1-03] 1-05) 1-01) 1-10 
2 a3 E E 
7, placed over 
Sirection tes U de nerteaad Sasea is nde eer s: = ae 
