GENERAL SIR EDWARD SABINE ON TERRESTRIAL MAGNETISM. 
269 
The mean secular change shown by this Table is an annual diminution of l'*94, or 
approximately 2'*0 ; which has been accordingly employed in the reduction to the mean 
epoch (1842 ’5) of all the observations at the Scotch Stations. 
In England the number of stations at which we have determinations of the Inclination 
at intervals of considerable duration (within the limits of the time comprehended by the 
survey) are much fewer, but they are sufficient to supply a satisfactory approximation 
to the amount of the secular change for the short intervals for which the corrections are 
required. On the eastern side of England we have five localities, at all of which the In- 
clination was observed at intervals comprehending from 2T5 to 24 years. These, with 
their respective geographical positions and the resulting annual decrease of the Inclina- 
tion at each, are shown in the following Table, viz. : — 
Observer. 
Date. 
Inclinatio 
observed. 
Phillips. 
1837*5 
O 
70 
42 
Ross. 
1838*5 
70 
43 
Sabine. 
1859*5 
69 
59 
Ross. 
1838*5 
69 
46 
Sabine. 
1861*5 
68 
55 
Ross. 
1838*5 
69 
29 
Sabine. 
1861*5 
68 
39 
Lloyd. 
1836-5 
69 
42 
Sabine. 
1860*5 
68 
42 
Sabine. 
1837*5 
69 
03 
Ross. 
1838*5 
68 
57 
Sabine. 
1860*5 
68 
06 
Stations. 
Lat. N. 
Long. E. 
Interval. 
Annual 
secular 
change. 
Scarborough 
Cromer 
Lowestoft .. 
Cambridge .. 
Margate 
54 17 
52 56 
52 28 
52 13 
51 23 
359 37 
1 19 
1 50 
0 07 
1 23 
years. 
21- 5 
230 
23- 0 
24- 0 
22- 5 
2-23 
2*22 
2-17 
2-50 
2-40 
On the western side of England we have four stations at which the Inclination was 
observed at nearly similar intervals ; these are : — 
Stations. 
Lat. N. 
Long. E. 
Stackpole Court... 
51 38 
355 05 
Lew Trenchard... 
50 40 
355 50 
Falmouth 
50 09 
354 54 
Plymouth 
50 22 
355 51 
Observer. 
Ross. 
Sabine. 
Sabine. 
Sabine. 
Ross. 
Sabine. 
Fox. 
Sabine. 
Ross. 
Sabine. 
Date. 
Inclination 
observed. 
Interval. 
Annual 
secular 
change. 
1837*5 
1860*5 
1838*5 
1859*5 
1837*5 
1838*5 
1 838*5 
1859-5 
1837*5 
1859*5 
69 56 
68 58 
69 19 
68 18 
69 16 
69 12 
69 14 
68 08 
69 06 
68 06 
years. 
23*0 
| 21*0 
I 21*5 
| 22*0 
2-52 
2*90 
3*07 
2*73 
We have, further, one English station, viz. Ivew, where the secular change of the 
Inclination has been the subject of a very careful and persistent inquiry for a much 
longer period (Proceedings of the Royal Society, vol. xi. pp. 144-162). In accordance 
with that discussion, we may safely regard an annual decrease of 2'*7 as approximately 
