MAGNETIC DECLINATION AT TORONTO, ST. HELENA, AND HOBARTON. 557 
181^ 53“ The mean amount of extreme easterly elongation is 4"-48, and of extreme 
westerly elongation 6"-43, making the whole range of variation in a lunar day due to 
the moon’s influence 10"'91. 
The question of any possible difference existing in the lunar diurnal variation at 
St. Helena when the moon is at her extreme distance on either side of the equator, has 
been examined in the same manner as has been already described in pages 554 and 555 
in the case of the Toronto observations, and with the same general result. The lunar 
diurnal variation appears to be the same whether the moon is N. or S. of the equator 
(or in this case N. or S. of the station). The amount of the lunar diurnal variation 
being altogether less at St. Helena than at Toronto, small irregularities naturally 
appear larger in proportion. The number of days included in the comparison is 
also less, extending through five years only instead of six. 
Hoharton. — The hourly observations at Hobarton which have been employed for 
this investigation are from January 1843 to December 1847 inclusive, comprehend- 
ing five years ; their number is 36,820, of which 3242 have been omitted as disturbed, 
being found to differ from the monthly mean at the same hour to an amount equalling 
or exceeding 3’4 scale divisions, or 2''41 in arc. 
The deflections are those of the north end of the magnet, and the signs imply, as’ 
at each of the other two stations, an easterly deflection when the — sign is used, and 
a westerly deflection when the -j- sign is used. The value of a scale division at 
Hobarton was 0 ' 71 . The deflections are exhibited in the following Table, which 
may be advantageously compared with the similar table at Toronto, page 552. 
Table VI. 
Lunar hours. 
Deflections. 
Lunar hours. 
Deflections. 
Lunar hours. 
Deflections. 
Lunar hours. 
Deflections. 
23 
Scale divisions. 
-h-os 
6 
Scale divisions. 
-•05 
10 
Scale divisions. 
+ •05 
18 
Scale divisions. 
—•08 
0 
+ •15 
7 
-•06 
11 
+ •14 
19 
— •15 
1 
+ •19 
8 
-•10 
12 
+ •25 
20 
-•15 
2 
+ •24 
9 
-•01 
13 
+ •33 
21 
— •12 
3 
4 
5 
+ •30 
+ •21 
+ •07 
14 
15 
16 
17 
+ •31 
+ •24 
+ •15 
+ •01 
22 
—•02 
This table exhibits, as at Toronto and St. Helena, a double progression, having 
two westerly and two easterly extremes at nearly opposite points of the hour-circle ; 
and still showing, as at the other two stations, the pheenornenon of the elongations 
in one direction being considerably greater than in the other direction. At Hobarton, 
as at St. Helena, the westerly elongations are the greatest, whilst at Toronto the 
easterly are greatest. The hours of extreme elongation differ both from those at 
Toronto and those at St. Helena. The values in Table VI. may be represented by 
