INTRODUCTION AND RESULTS. 
245 
The mean result of this series is 3-5350; and the Inclination from observations 
made on the same days 7 5° 15'-8 : hence we have the total force 13-897. 
Finally, we have another series made with Nos. 30 and 31 in April 1846, and on 
this occasion unusual care was bestowed on the observations both of the Force and 
of the Inclination, preparatory to a repetition with the same instruments at Woolwich, 
for the purpose of making the comparison between Woolwich and Toronto as rela- 
tively correct as possible. The particulars of these observations are contained in 
the following Tables : — 
Table II. — Observations on the absolute Horizontal Force made at Toronto with 
the Survey bars Nos. 30 and 31, in April 1846, reduced to the mean reading of 
the Bifilar Magnetometer for the day of observation. 
Date. 
Bars. 
Distances. 
Bifilar. 
Mean of the day. 
Sc. div. 
Therm. 
579-5 
55-0 
580-5 
55-4 
592-4 
51-7 
595-6 
51-2 
At the observation. 
Sc. div. I Therm. 
Deflections. 
Vibrations. 
Corresponding bifilar. 
Angles. 
Therm. 
Times, 
Therm. 
Sc. div. 
Therm. 
10 2^-9 
7 54-5 
11 28-0 
8 39-4 
10 28-8 
7 54-9 
6 8-0 
11 23-3 
8 36-0 
6 39-4 
59-2 
58-2 
48-5 
48-8 
48-7 
48-3 
48-3 
61-2 
62-0 
62-5 
4-2061 
4- 2062 
40084 
40114 
5- 0985 
o 
50 
50 
50 
50 
50 
581-0 
615-6 
573-2 
578-7 
586-7 
54-5 
57 1 
54-5 
56-6 
51-6 
50995 
4-8685 
50 
50 
592-3 
588-2 
52-7 
51-2 
4-8749 
50 
594-9 
53-6 
Value 
of in . 
Value 
of X. 
April 
6 . 
6 . 
7- 
7. 
8 . 
8. 
8 . 
9. 
9. 
9. 
31 
31 
30 
30 
31 
31 
31 
30 
30 
30 
feet. 
1026 
1126 
1026 
1-126 
1-026 
1-126 
1-226 
1026 
1126 
1-226 
572- 6 
606-6 
576-5 
573- 8 
581-6 
584-0 
586-2 
581- 7 
583-2 
582- 5 
56- 3 
57- 0 
56-2 
56-5 
52-2 
521 
521 
52-8 
52-7 
52-6 
0-349 
0-349 
0-380 
0-380 
0-348 
0-348 
0-348 
0-379 
0-379 
0-379 
3-538 
3-535 
3-530 
3-530 
3-535 
3-535 
3-533 
3-532 
3-531 
3-531 
3-533 
Table III. — Observations of the Inclination made on the Pedestal of the Telescope 
used in the Observations of Vibration, and intended for comparison with a Base 
series of observations of the absolute Horizontal Force. April, 1846. 
Date. 
Observer. 
Poles direct, 
Poles reversed. 
Mean 
Inclina- 
tion. 
a . 
a '. 
l ". 
aJ ". 
Mean. 
b . 
b '. 
b ". 
b "‘. 
Mean. 
April. 
6 A M. 
L. 
o 
74 
55-8 
75 
42-9 
o 
75 
2^1 
74 
43-6 
75 
12-8 
75 
4-8 
O 
75 
31-6 
o 
75 
33-1 
75 
2-8 
75 
18-1 
75 
15-5 
P.M. 
H. 
75 
3-8 
75 
45-6 
75 
32-8 
75 
1-7 
75 
21-0 
75 
2-2 
75 
30-9 
75 
27-6 
74 
46-2 
74 
11-7 
75 
16-3 
7 
A.M. 
H. 
75 
4-3 
75 
34-8 
75 
34-8 
75 
40 
75 
19-4 
74 
57-4 
75 
41-8 
75 
31-4 
74 
444 
75 
13-7 
75 
16-5 
8 
P.M# 
H. 
75 
4-3 
75 
31-2 
75 
24-9 
74 
48-1 
75 
121 
75 
1-4 
75 
45-3 
75 
33-2 
75 
1-4 
75 
20-3 
75 
16-2 
A.M. 
Y. 
74 
54-9 
75 
41-1 
75 
240 
74 
38-2 
75 
9-5 
75 
35 
75 
27-7 
75 
39-7 
74 
56-3 
75 
16-8 
75 
13-1 
P.M. 
H. 
75 
3-7 
75 
431 
75 
33-9 
75 
0-8 
75 
20 4 
75 
1-1 
75 
29-1 
75 
31-3 
74 
44-5 
75 
11-5 
75 
16-0 
9 
A.M. 
L. 
75 
6-3 
75 
31 6 
75 
30-2 
75 
1-0 
75 
19-3 
75 
2-4 
75 
37-2 
75 
39-3 
75 
2-6 
75 
20-3 
75 
18-8 
11 
P.M# 
L. 
74 
56-1 
75 
27-5 
75 
33-2 
74 
45-4 
75 
10-5 
74 
58-8 
75 
42-9 
75 
36-7 
75 
0-6 
75 
19-2 
75 
150 
A.M. 
W. 
74 
56-2 
75 
38-4 
75 
21-2 
74 
46-0 
75 
10-4 
75 
30 
75 
30-8 
75 
310 
75 
2-2 
75 
16 7 
75 
13-6 
13 
A.M, 
H. 
75 
3-2 
75 
39-7 
75 
341 
75 
3-3 
75 
20-1 
75 
0-5 
75 
29-3 
75 
28-4 
75 
45-6 
75 
10-9 
75 
15-5 
Mean Inclination, corresponding to the series of absolute horizontal Force.. 
75 15-65 
The instrument employed was Gambey’s circle. Needle 1 was used for all the a.m. 
observations, and Needle 2 for all the p.m. observations, with the exception of the a.m. 
observation on the 13th, for which 2 was employed. The observers were, L. Lieut. 
Lefroy ; Y. Lieut. Younghusband ; H. Sergeant Henry ; W. Sergeant Walker, 
mdcccxlvi. 2 K 
