178 



REPORT 1859. 



Table IX. (continued.) 



Station. 



Makerstoun 

 Edinburgh 



Portree .... 

 Stomoway. 



Callinish . 

 Cross 



Loch Inver 



Durness.. 

 Thurso .. 

 Lerwick . . 

 Kirkwall 



Wick 



Golspie .. 

 Dingwall 



Date. 



mX. 



Ardrossan . . . 

 Port Askeg 

 Bridgend ... 

 Tobermorie 

 Grlemnorren 

 Bahnacarra 

 Kyleakin . . . 

 Broadford . . . 



Aug. 



1858. 

 July 7 



9 

 10 

 12 

 17 

 19 

 24 

 26 

 28 

 29 

 31 

 31 

 3 

 6 

 6 

 9 

 11 

 11 

 16 

 16 

 16 

 19 

 23 

 30 

 1 

 1 

 1 

 4 

 7 

 9 



Greenwich 

 mean time 



of ob- 

 servation. 



X* 



Sept. 



1-6624 

 1-6573 

 1-6663 

 1-6718 

 1-6722 

 1-5374 

 1-6382 

 1-5838 

 1-58(12 

 1-5854 



1-5951 



1-5604 

 1-5655 

 1-5566 

 1-5459 



1-5357 

 1-5260 



1-5339 

 1-5380 

 1-5594 

 1-5103 

 1-5475 

 1-5572 

 1-5582 

 1-5531 

 1-5727 

 1-5647 



3 

 11 



O 



1 

 4 

 5 

 3 



43 p.m 



51 A.M. 



38 p.m 



18 



32 



17 



14 

 49 

 7 10 

 11 30 a.m. 



•14080 

 14079 



•14346 

 •14260 

 14216 

 •14199 



•15436 



Grenwich 

 mean time 



of ob- 

 servation. 



h m 



11 56 A.M. 



42 r.M 



Calculated 

 value of m. 



X. 



Total 

 force. 



41 P.M. 

 59 A.M 



31 I>.M 



2 

 21 



1 10 



1 57 

 5 2 



10 23 a.m 



2 9 p.m 

 17 



19 A.M 

 10 P.M 

 56 

 53 



3 

 57 



15005 



14979 

 •14956 



: i52oi' 



15207 



•15354 



•15355 



41 



1 50 

 12 



2 41 

 6 17 



2 35 



10 3 A.M 

 10 35 



•48750 



•48748 



10 58 



11 31 



2 53 p.m 



3 17 



1 

 11 

 2 

 2 

 1 

 3 

 1 



•15675 

 •15288 

 •15266 



2 21 



18 



1 13 



■48733 

 •48730 



•48726 



•■48720 



•48714 



•48711 



•48707 



•48699 



•48696 

 •48693 

 •48691 



34626 



3-4101 

 3-3988 

 3-4184 

 3-4293 

 3-4317 

 31560 

 3-3616 

 3-2489 

 3-2551 



3-2546 



3-2737 

 3-2039 

 3-2085 

 31949 



3-1730 



31446 



31574 

 3-2017 

 31041 

 31815 

 31937 

 31996 

 31894 

 3-2299 

 3-2134 



10-545 



10-586 

 10-551 

 10-621 

 10-655 

 10-675 

 10-661 

 10-899 

 10-634 

 10-636 



10-682 



10-605 



1 10-689 



10-666 



10-742 



10-512 



10-697 

 10-674 

 10-738 



L 10-721 



10-700 

 10-692 

 10-632 



It may be observed, in passing, that the moments in the above table show 

 us that the loss of magnetism of the needle was much more rapid during the 

 first year than the second ; the reason being, that the needle had been mag- 



netized about the beginning of 1857, and v 



therefore 



during 



the first 



year's observations a comparatively new magnet. 



It is now necessary to combine our total forces by the method of least 

 squares. If we exclude Loch Inver and Glenmorven, both of which seem to 

 be much affected by local disturbance, we obtain/, or the total force at the 

 central station, lat. 56° 55' N., long. 4° 21' W. = 10-614 ; m, or the angle 

 which the isodynamic lines make with the meridian=— 52° 45', or then- 

 direction is from N. 52° 45' E. to S. 52° 45' W. ; and r, or the rate of in- 

 crease of total force in a normal direction = -000961 (British units) for each 

 geographical mile. 



It will be remembered that the unifilar used in the Scotch survey gave 

 the total force at Kew=10295. 



Let us suppose that this number represents with sufficient accuracy the 

 total force in London, which is only a few miles from Kew, on 1st Jan. 

 1858. 



