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 116
the returning part of the wirewere upon the same side of the needle with the otherpart, and at an equal distance from it. But a wiretransmitting an electrical current, when passing belowthe needle, will produce an effect the reverse of thatproduced by one passing above, if tlie current in bothcases… … 100 DAVISS MANUAL. above. This is the case with the arrangement hererepresented. The two portions of the wire are notallowed to touch each other where they cross, butare insulated at that point by some non-conductor ofelectricity, as by being wound with thread. Instru-ments of a variety of forms…
