quadrant (inductance)

A unit of inductance, the name chosen by the Second International Conference of Electricians (Paris, 1889) and renamed henry at the Third Conference (Chicago, 1893). Apparently “quadrant” was suggested by the unit’s having a value equivalent to 1,000,000,000 centimeters, which is the approximate length of a quadrant of the earth, due to the manner in which the meter was originally defined.

Report of British Association 1889, page 43.



The quadrant is the practical unit of self-induction adopted by the B.A. Committee of electrical standards, 1889 = 10⁹ absolute C.G.S. units of induction. It is nearly identical with the secohm.

Latimer Clark.
A Dictionary of Metric and Other Useful Measures.
London: E & F.N. Spon, 1891.


The henry has been known also by the names “quadrant” and “secohm.” Both names are based on dimensional considerations. The length of a quadrant or quarter of the earth's circumference is approximately 10⁹ centimeters and a henry is 10⁹ “centimeters” of inductance.

[U. S.] Department of Commerce.
Circular of the Bureau of Standards No. 60.
Electric Units and Standards.
Washington: U.S.G.P.O., 1916.
Page 45.

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