The Bakerian Lecture: A Magnetic Survey of the British Isles for the Epoch January 1, 1886 . North-West England, North Wales, and Galloway. The valley line which bounds it on the east has been drawn through the centre ofthe region of low Vertical Force which exists there (see Plate XI). The southernpart is obtained from the Horizontal Force disturbances (see Plate X.). SURVEY OF THE BRITISH ISLES FOR THE EPOCH JANUARY 1, 1886. 305 At Dumfries and Carlisle the disturbing forces are small, and coincide in directionwith the valley line, , they fairly represent the resultants of two attraction
The Bakerian Lecture: A Magnetic Survey of the British Isles for the Epoch January 1, 1886 . North-West England, North Wales, and Galloway. The valley line which bounds it on the east has been drawn through the centre ofthe region of low Vertical Force which exists there (see Plate XI). The southernpart is obtained from the Horizontal Force disturbances (see Plate X.). SURVEY OF THE BRITISH ISLES FOR THE EPOCH JANUARY 1, 1886. 305 At Dumfries and Carlisle the disturbing forces are small, and coincide in directionwith the valley line, , they fairly represent the resultants of two attractionsexerted on each side of it. At Stranraer, and in the Isle of Man, our disturbingHorizontal Forces act towards the south, and this result is confirmed by those Eig. North-West England, North Wales, and Galloway. deduced from Welshs observations at Stranraer and Newton Stewart. They aremuch larger than ours, and at Dumfries the southward tendency is more marked. Itmust be remembered, however, that the calculations by which these results have beendeduced from the 1857 survey have been conducted on the assumption that the MDCCCXC.—A. 2 B 306 MR. A. W. RtTCKER AND DR. T. E. THORPE ON A MAGNETIC Scotch, isomagnetics are linear functions of the coordinates which determine thegeographical position, and that the errors involved in the assumption would chieflyaffect stations such as these, which are on the border of the district. If it is necessary to prove that these results are independent of the method ofcalculation, Fig. 28 is sufficient for the purpose. The lines of equal Horizontal Force converge in a most remarkable way towardsNorth Wales, which is one of the most certain indications of a centre of the Declinations at Holyhead an
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectproceed, bookyear1890
