Autograph letter signed (carbon copy) to Charles Tilston Bright

1862. Very Good.

Jenkin, Henry Charles Fleeming (1833-85). A.L.s. (carbon copy) to Charles Tilston Bright. [London], January 9, 1862. 2pp. 254 x 202 mm. Small holes punched in left margin, traces of mounting present. Provenance: Latimer Clark.

Jenkin, a British engineer, served as secretary of the British Association's Electric Standards Committee (formed in 1861), which was responsible for setting and naming the standard units of electrical quantity and resistance. His correspondent, Charles Bright, was co-author with Latimer Clark of "On the formation of standards of electrical quantity and resistance" (1861), which led directly to the formation of the committee. Jenkin here informs Bright that

"the Committee of the British Association on Standards of Electrical Resistance are anxious to have the benefit of your valuable advice and propose from time to time to take the liberty of consulting you.

"What the National Standard should be and of what metal it should be made are questions which will be brought before you at a later date when the Committee are able to acquaint you with the results of experiments now in progress. Meanwhile, the Committe would be glad tolearn what formof Standar Resistance you could reoommend.

The committee wish to compare coils of copper wire wound in various ways, in order to determine the merits of each plan and would be happy to send you a length of copper wire to be wound under your care if you feel disposed to to the trouble and expense of preparing a coil. The Committe are anxious to obtain a coil which shall combine good insulation, convenience of form and permanence of electrical conditions, with the property of rapidity [?], assuming the temperature of the surrounding medium. Copper has been chosen because it is a metal which will bring out clear the possible defects of any of the prosed forms. . . ." Origins of Cyberspace 166.

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