[N008214], Technical Note, Francis Robbins Upton, June 11th, 1879


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[N008214], Technical Note, Francis Robbins Upton, June 11th, 1879

Editor's Notes

"New machine speed 268 revo on its own field very slow in coming up"; I do not understand how this is for yesterday having the Gramme machine on the field giving a current of 11.2 Webers the Edison only gave an E.M.F. of 50.4 Volts [now getting 59.3] See page 223 where reading today shows an E.M.F. of 60.5 there being 8.26 Webers on field. Yesterdays reading perhaps wrong. The speeds were the same by measurement"; "Perhaps having the magnet in circuit may increase the E.M.F. acting as a reservoir to bridge over the small variations Not so"; Ex Put the Gramme machine through the magnet and test its EMF with and also without magent in circuit No dif Found that the dynamometer must be shaken as it is sluggish of movement. Dust the reason for this on the surface of the Hg.; several pages of tests follow based on Gramme on and off; "As the magnet is nearly saturated the square of the E.M.F. are proportional to teh strength of the current around the magnet see p. 212 The law for this to be thoroughly tested"; notes on standard daniells cell and other with porous cup also a siphon cell and tests to determine why porous cup cell shows greaer EMF, finds siphon has large resistance and fluid of different density, "Better use the porous cup being more exact"





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