[NM024012], Technical Note, Arthur Edwin Kennelly, August 2nd, 1889



"Carrying Capacity of Conductors. With the view of determining more closely the coefficients of convection and radiation, took a series on three bare bright copper wires (two of which had been used before in the out of doors test) and suspended across the room in the place of the strips whose test is given on page 7. the height of the wires was about 250 cm and their distance apart about 50. The two larger were tested in circuit with the long range ammeter and the smaller separately in circuit with the [illeg]. Table of results includes lethth, diam, surface area, resistance, restivitiy, conductivity, etc. [Several trials.] p. 14: "From the observed dissipation of heat by the bright bare suspended copper wires and strips, we obtain the following analysis of the convection and radiative emissity at different temperature elevations. [Tables followss]. "This very remarkable agreement proves the application of Dulong & Petits law....[p. 15] In the present form of strand phonograph conductor there are 70 wires each 0.0088 diam = 77.5 cm each x 79 = 6125 cm in all; that is practically equivalent to a number 14 BWG. ## The accepted limit of the length of this strand that can be used with the phonograph is 12 feet doubled = 24 fee. [chart follows showing BWG equivalents.]







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[NM024012], Technical Note, Arthur Edwin Kennelly, August 2nd, 1889

Microfilm ID



Thomas A. Edison Papers, School of Arts and Sciences, Rutgers University