146 
FIFTH REPORT-1835. 
Table Y. 
Dip.—Final Results. 
Place. 
Date. 
Dip (1). 
Dip (2). 
Mean. 
o • 
O / 
o ' 
London . 
August 1834 
69 18-9 
69 18-9 
Dublin . 
Aug., Sept. 
71 3-8 
71 5-1 
71 4*1 
Limerick. 
.Tulv. Aiio*. 
71 9-5 
71 9*5 
GlpncrnpifF 
Spnt, 27, 28 
71 7-5 
71 7*5 
T\illarnpv. 
Oct. 4. 
71 10-5 
71 10-5 
Tul la . 
12. 
71 21*8 
71 2F8 
Carlin "ford. 
13. 
71 26*3 
71 32-1 
71 28*2 
Armagh . 
14, 15. 
71 41-5 
71 37-8 
71 40-3 
Colerain .. 
20. 
71 25 6 
71 237 
71 250 
Carn . 
21. 
71 57-8 
72 1-1 
71 58-9 
Strabane. 
23. 
72 F6 
71 50-9 
71 58-0 
Fnniskillen 
24. 
71 58 0 
71 58-0 
Fermov 
Dec. 2. 
70 46-3 
70 46-3 
London . 
Sept., Oct. 1835. 
69 16*3 
69 19-8 
69 17*3 
Dublin . 
Sept. 4-—15. 
71 3-5 
71 2-0 
71 3-0 
Markree .. 
Aug. 21. 
72 3-6 
72 7*1 
72 4-8 
Ballina . 
22. 
72 11-9 
72 3-3 
72 9-0 
Belmullet . 
24. 
72 12-7 
72 90 
72 11-5 
Achill Ferry ... 
25. 
72 4-4 
72 47 
72 4-5 
Galway . 
28. 
71 31*9 
71 28*9 
71 30*9 
Ennis . 
71 1F5 
71 10-6 
71 11*2 
Limerick. 
29. 
71 F9 
70 59-0 
71 0-9 
Cork . 
31. 
70 39-3 
70 447 
70 41-1 
Waterford . 
Sept. 1. 
70 47‘6 
70 50-3 
70 48-5 
Broadway . 
2. 
70 29-4 
70 43-1 
70 34-0 
Gorey. 
3. 
70 53-4 
70 54-6 
70 53*8 
Rathdrum . 
70 51*1 
70 52-3 
70 51-5 
Dublin .. 
Nov. 5, 6. 
71 1*3 
71 F3 
Limerick. 
July, Dec. 
71 60 
71 6-0 ' 
Ballybunan. 
Nov. 8. 
71 19-3 
71 19-3 
Valentia . 
12. 
71 5-2 
71 5*2 
Dingle.. 
18. 
71 7*9 
71 7-9 
Tul la . 
Dec. 10. 
71 26 7 
71 26-7 
Yougbal . 
29. 
70 39*2 
1 
70 39-2 
The dip being known, the intensity will be given by the formula 
4) sin (5 — 0) = (3 cos $, (2) 
in which (3 is constant, and the measure of the force exerted 
by the earth on the needle. This force, however, varies with 
the temperature to which the needle is exposed j and it is ne¬ 
cessary to determine the amount of this variation before we can 
know the relative values of the terrestrial magnetic force at dif¬ 
ferent stations. Let t, then, be the observed, and t 1 the standard 
temperature, and let <p r be the value of corresponding to the 
latter; then 
t'), (3) 
