Identifier: philtrans08603087 (find matches)
Title: The Bakerian Lecture: A Magnetic Survey of the British Isles for the Epoch January 1, 1886
Year: 1890 (1890s)
Authors: Rucker, A. Thorpe, T.
Subjects: Proceedings of the Royal Society of London Philosophical Transactions of the Royal Society
Publisher: Royal Society of London

View Book Page: Book Viewer
About This Book: Catalog Entry
View All Images: All Images From Book
Click here to view book online to see this illustration in context in a browseable online version of this book.

Text Appearing Before Image:
s larger than the calculated value._ _ — Contour lines of equal Vertical Force disturbance. In fig. 19 we have depicted the disturbing Horizontal Forces. They are drawn inthe proper directions, and to a scale on which 0*9 mm. corresponds to 0*001 metricunits. They fulfil the above conditions exactly, and we think leave no doubtthat in the south-east of England over an area of 10,000 square miles the lines ofmagnetic disturbing force tend to a centre which lies near to and probably betweenTwyford and Henley-on-Thames. We have treated this district in great detail,because we rely upon these results to prove that the methods of calculation anddeduction adopted are satisfactory, at all events in districts where the surface rockor soil is non-magnetic. If the results attained elsewhere present greater difficulties !86 ME. A. W. RUCKER AND DR. T. E. THORPE ON A MAGNETIC it must be due to the greater complications introduced by the interference of local with regional disturbances. Fig. 19.
Text Appearing After Image:
Disturbing Horizontal Magnetic Forces in South-Eastern England. The maps which have been used to illustrate our discussion of the Reading disturbance give indications of other minor centres, and in particular the isogonals areconsiderably distorted in the north. It appears that if we draw a line throughKings Lynn (No. 100), Spalding (No. 140), Melton Mowbray (No. 116), Lough-borough (No. 109), Birmingham (No. 63), and Malvern (No. 112), the district throughwhich it passes is the seat of local disturbances, which, though individually less wide-spread than that already discussed, are nevertheless of considerable intensity. We will now investigate several points in this neighbourhood. It will not benecessary to do this in the same detail as before. The places to be considered lie sonear to the borders of the district already studied, that methods which are so consis-tent in the one cannot be subject to any important error in the other. The Wash. We have discovered a. remarkable disturban

Note About Images