Appleton's dictionary of machines, mechanics, engine-work, and engineering (1869)
New York, Appleton · leaf 325
2095. R … magnetic needles, with their poles reversed to each other, are fixed on a central rigid axis, so as to neu-tralize the directive power of the needles, merely allowing a sufficient force to bring the whole into themeridian. This system is suspended by two parallel threads of unspun silk r n, one of…
Mechanical engineering
Internet Archive · Gerstein Library, University of Toronto · Public Domain Mark 1.0. Free to use for anything.
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