[LB008269], Letter from Thomas Alva Edison to George Frederick Barker, May 20th, 1881


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[LB008269], Letter from Thomas Alva Edison to George Frederick Barker, May 20th, 1881

Editor's Notes

I will find out when that was published about the Chalk [Factory] & let you know as soon as possible. I would be glad to see your friend Stanley when he calls.##What machine do you propose to use for lighting your homes. If you have one please get the electro motive force of the with the nearly saturated constant field with the machine open also give me the internal resistance of the bobbin and the resistance of the field. I may have to make your lamps to suit your machine. We make [16] candle lamps of 100 to 110 volts also eight candle lamps [100 to 200] volts also eight candle lamps from 50 to 55 volts also 16 candle lamps with from 50 to 55 volts.##We have not given any of the manuscript of the book goes up to [to] the privates yet but we will give you proof sheets as soon as we get them. I would thank you for a copy of your [September] notes when for the Smithsonian Report when published.##If there is any other Scientist that you want me to send lamps to I will do so with pleasure. I am very delighted to hear of Professor [Shorts] success at Denver.##I tested a Dynamo last week of a new form but the same [surges] as the one you saw at Menlo Park and it gave remarkable results. Got 74 volts with an [in----] resistance of [-/0000] of an ohm. This is just 27 times better than has ever been done by force by Siemens or anyone else and [---] [each] action has been brought down to a point so low that it can almost be left out of any calculations. Hence the efficiency of this machne is up somewhere near the conductivity of the copper The other advantage is that the whole apparatus is insulated with mica; no covered wire is used By a new phenomenon which I have lately discovered I am able to prolong the life of the lamps and shall change their economy from [8600] foot pounds for sixteen candles to [2000] foot pound for 16 candles. The Lord only knows where the economy is going to stop! Telegraph me when you will be here




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