TransactionsPublished under the care of the General Secretary and the Treasurer . nd attracting pole {N^) being east of the south-end at-tracting poles {S^ S^); the other in the southern hemisphere, thedirection of magnetization being the reverse of the former, thenorth pole (iYo) lyig iio^^ ^^^st of the south pole (>S2). The polesof the two systems are situated, approximately, near the 40 — this is even true of the tertiary system N^S:^. The secondary magnetic equators (the lines along which the re-sidual vertical force is zero) occupy practically the same positionsfor the th
TransactionsPublished under the care of the General Secretary and the Treasurer . nd attracting pole {N^) being east of the south-end at-tracting poles {S^ S^); the other in the southern hemisphere, thedirection of magnetization being the reverse of the former, thenorth pole (iYo) lyig iio^^ ^^^st of the south pole (>S2). The polesof the two systems are situated, approximately, near the 40 — this is even true of the tertiary system N^S:^. The secondary magnetic equators (the lines along which the re-sidual vertical force is zero) occupy practically the same positionsfor the three epochs. It is as yet too early to decide as to any prob-able secular shifting of the positions of the secondary poles. Theinterval is too short, in view of the meagerncss of the data onwhich the charts depend, to make certain any deductions. What has thus far been gained by the decomposition of theearths total magnetic field into a primary and into a secondary one ? , In the first place, the residual field clearly exhibits the fact that 268 BAUER: EARTHS MAGNETIC BAUER: EARTHS MAGNETIC FIELD. 269 it is not a heterogeneous one, but, in general, remarkably sys-tematic in its structure. There is, therefore, a very strong indi-cation that it is produced by some distinct physical cause operatingin the same general manner over the entire earth. The hope isthus clearly held out that we may still further resolve the residualfield, starting with fundamental, physical causes. My present belief is that the chief physical cause of the re-sidual field is to be referred to the distribution of temperaturewithin the stratum of the earths crust here concerned. There is a very remarkable correspondence between the prin-cipal features of the residual magnetic field and those exhibited ona chart of isabnormal temperatures. It is found that the earth asa magnet acts like any other magnet as regards application of , wherever the earths surface is relatively warm, on the aver-
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Keywords: ., bookcentury1900, bookdecade1900, bookidtr, booksubjectelectricity
