Davis's manual of magnetism : including galvanism, magnetism, electro-magnetism, electro-dynamics, magneto-electricity, and thermo-electricity (1854)
Davis, Daniel · Boston : Palmer and Hall · leaf 251
Hence the lines traced by the two currentsin these experiments may be irregular, though thetendency to converge is perfectly evident. 371. Contracting Helix. — The mutual attrac-tion between different portions of the same currentmoving in the same manner, may be rendered evi-dent by the instrument… … end of the helix dips into mercury contained in aglass cup with a metal bottom, by means of which the mercury is brought Fi^. 160. . \. .. * into connection with the other screw-cup.When the battery isapplied, the portions ofthe current traversingthe different turns ofthe helix of course…
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