344 MAGNETIC SURVEY OF A PART OF THE SOUTHERN HEMISPHERE. 
May 1845 (page 362 in seq.), which are the last received from that station, give a mean 
result of 4*482, the mean inclination during the same month being —53° 25'*5. Com- 
bining these with the determination at Woolwich in No. VII. of these Contributions*, 
we have the total force at the Cape in the arbitrary scale 0*993. The ratios deter- 
mined by Mr. Fox’s statical apparatus (page 363 in seq.) by separate needles are 1*000 
and 1*006 : the value of the total force at the Cape as a base station for the observa- 
tions of the Pagoda has therefore been taken as 1*000. 
As Lieut. Smith did not touch at the Cape on his passage to Hobarton, and as the 
needle which Lieut. Dayman had employed on his homeward passage was broken at 
the Cape before observations had been made with it, and consequently before the 
series between Hobarton and the Cape could be connected with the latter station, it 
has been necessary to employ Hobarton as the base station of both these series. I 
have already stated in Nos. V. and VI. of these Contributions, the results of the ob- 
servations which were made to determine the absolute horizontal force at Hobarton 
between 1840 and 1844 ; viz. by Sir James C. Ross in 1840 and 1841, with magnets 
of fifteen inches in length -f*; by Lieut. Kay in 1841 and 1842, with magnets of the 
same length;}; ; by Lieut. Kay in 1844 with magnets of twelve inches^, and with 
others of 9*18 and 7’5 0 inches ||. I have now to add the results of twenty-four de- 
terminations made by Lieut. Kay between November 1844 and September 1845, with 
magnets of various lengths, as shown in the following table : — 
Magnets and their length. 
Date. 
No. of 
distances. 
Horizontal 
force. 
Suspended. 
Deflecting. 
in. 
in. 
7-50 
9*18 
Nov. 7, 1844. 
3 
4*5108 
7*50 
9*18 
Sept. 9, 1845. 
3 
4*4810 
A 57 3-00 
D xv. 3*67 
Dec. 7, 1844. 
3 
4*5316 
A 57 3-00 
Dxv. 3*67 
Dec. 9, 1844. 
5 
4*5118 
| A 57 3-00 
D xv. 3*67 
Dec. 11, 1844. 
5 
4*4954 
A 57 3-00 
D xv. 3*67 
Jan. 12, 1845. 
5 
4*5058 
A 57 3-00 
Dxv. 3*67 
May 5, 1845. 
3 
4*4997 
A 57 3-00 
D xv. 3*67 
Aug. 15, 1845. 
5 
4*4762 
A 57 3-00 
D 9 3*67 
Aug. 19, 1845. 
5 
4*5104 
A 57 3-00 
D 9 3*67 
May 6, 1845. 
3 
4*5076 
A 57 3-00 
A 19 3*02 
Aug. 20, 1845. 
5 
4*4905 
A 52 3-00 
D xvi. 3*67 
Jan. 19, 1845. 
3 
4*4940 
R 1 3-00 
D xvi. 3*67 
Aug.28, 1845. 
4 
4*4970 
I 12 2-45 
A 19 3*00 
Dec. 13, 1844. 
5 
4*4954 
I 12 2-45 
A 19 3*00 
Dec. 13, 1844. 
5 
4*4899 
I 12 2-45 
A 19 3*00 
Dec. 15, 1844. 
5 
4*4865 
I 12 2-45 
A 19 3-00 
Jan. 14, 1845. 
5 
4*4809 
I 12 2*45 
A 29 3*00 
Aug. 26, 1845. 
5 
4*5016 
I 12 2-45 
A 23 3-00 
Aug. 22, 1845. 
5 
4*4994 
I 1 2-45 
A 23 3-00 
Dec. 20, 1844. 
3 
4*5046 
I 1 2*45 
A 23 3*00 
Dec. 23, 1844a 
3 
4*5121 
I 1 2-45 
A 23 3*00 
Dec. 26, 1844. 
5 
4*5020 
I 1 2-45 
A 23 3*00 
Jan. 15, 1845. 
5 
4*5082 
I 1 2-45 
A 23 3*00 
May 9, 1845. 
3 
4*4970 
Mean 
4*4992 j 
* Philosophical Transactions, 1846, p. 246. 
X Ibid. p. 168 (note). § Ibid. 1844, p. 111. 
f Ibid. 1843, p. 168. 
|| Ibid. p. 112. 
