Electricity for public schools and colleges (1891)
Larden, W. (Walter), b. 1855 or 6 · London : Longmans · leaf 311
The needle is a very small bit of magnetised watch-spring. Having little i?iass and inertia, its movements follow anyfluctuations in the current almost instantaneously. (iii.) A controlling magnet enables one to vary the sensitive-ness of the instrument at will, as explained in § 9. (iv.) The same…
Electricity
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