[LM003115], Letter from Samuel Insull to Edward Hibberd Johnson, April 1st, 1883


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[LM003115], Letter from Samuel Insull to Edward Hibberd Johnson, April 1st, 1883

Editor's Notes

[highly selectable on 3-wire system] Yours of 10th rcd & TAE was pleased with the info & to know exactly how matters stand. He approves your plans for developing the business. Hopkinson: TAE is confindent H has nothing in his patents to touch us with. Says the original idea is embodied in his expts on running A & B lamps from the same machine in principle and by putting a 3rd brush on the commutator midway between the two ordinary brushes and thus using the wires running from the ordinary brushes for one circuit (for A lamps) & one wire running from the middle brush and the third wire running from one of the ordinary brushes for the other circuit (for B lamps) thus having A and B circuit from the same machine all the lamps in multiple arc & all by the introduction of one extre and one extra brush. Upton says this was done away back at Menlo." TAE showed it to me early last summer at Menlo. This discovery can't be claimed by Hopkinson, as your letter clearly shows; *you* had to tell him the value of it, that 62.5% of copper could be saved." TAE says he doesn't fear Hopkinson in this. Discusses in some details dynamo improvements & Hopkinson's claims to same. TAE says he's not ready to write you about all this himself so I said I would. "Of course I am not an electrician but after reading the first three pages of this to Edison he said it was correct so that will make up to a certain extrent for my lack of knowledge." Enclose you minutes of the Standardizing Committee. APRIL 2 POSTSCRIPT. TAE cabled you today; says he can't see how Hopkinson can get patent you say he intends to try for. Will write you more.





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