[LB012049], Letter from Thomas Alva Edison to Edward Hibberd Johnson, April 6th, 1882


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[LB012049], Letter from Thomas Alva Edison to Edward Hibberd Johnson, April 6th, 1882

Editor's Notes

I enclose you herewith Express receipt for shipment of Six Telephones together with my account against the United Telephone Co [amounting] to $153.25 which please see is sent out as early as possible.##As to the Telephone to the testing of which I devoted all last [--sday]##No 1. [---] silk coated with plumbago and with plumbago between. Good##No 2. Silk cut fine coated with and mixed with plumbago. Better##No 3. silk coated & cut very fine mixed with slight amount of plumbago. This is about as [loud] as a medium carbon Transmitter & better than either 1. & 2.##No 4. Silk fluf cut very fine coated and mixed with plumbago. Same loudness as No 3. & louder than magneto telephone##No 5. Fine fluf coated and mixed with Lampblack##No 6. Discs of Silk worked with plumbago. Not very loud.##We used regular induction coil and these cells [Leclanche]. For some reason when we used two carbon cells the telephone did not work so well as with three Leclanche.##To make fluf got some raw untwisted silk, tangle up a lot of it then keep separating it until it is all fluffy. Then take some ordinary carbon buttons powder them up & thoroughly mix the powder with the fluf. Then take a pair of shears and cut it up in 100 inch lengths. Afterwards pick & work it & you will find that it will hold the lampblack. Put it in receptacle in Telephone for the button & press it down with a flat disc until it is even.##With plumbago you can do the same but you had better make this solution of gum [destrine] in water and mix plumbago to a thin paste. Then take the fluffy silk in your hand and work the paste into it afterwards pulling out the material thus obtained until they are no lumps left in it. Then let it stand for several hours, twist it up and cut it in [100] inch lengths so that it will be a fine fuz. Then work [somewhere already] into it & put it into receptacle flatening it with flat disc as before##The silk disc are not loud as we did not have time to work the plumbago in. It should be worked with a plumbago & distrine paste and [--icked] through so as to get plumbago through the fibre. Then allow it to dry & rub on another coat without [puicking] the silk, then let it dry & rub on another coat & so on the more coats the louder it will talk##All these Telephones are a little louder than magneto telephones




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