[D8731AAB], Letter from Charles Lever to Charles Batchelor, March 15th, 1887


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[D8731AAB], Letter from Charles Lever to Charles Batchelor, March 15th, 1887

Editor's Notes

"I have been away from home for sometime not having been in good health, but on my return home have been thinking about the lamp I promised to send so long ago. In a few days after you receive this letter you will also receive duty free & all charges paid a small arc lamp 500 candle power actual which is worked on incandescent circuits and that is why it has not cut out. It is of the short arc type and works with 30 to 35 volts [---] and 10 amperes with 10 millimeter carbons. It is not a new lamp, but has been successfully used in engineering works etc. With 110 volts I thinkk you would be able to work 3 in series easily. Hard carbons such as Wallace diamond will suit, as it works with a short arc. The glycerine is put in the little dashpot and on just moving the lever armature up and down it soon works through to other side of plunger. You can send any current you like through the carbons as there is no main magnet to injure, but they are generally suited to work with 10 or 12 amperes. The magnet is only made to stand an arc of 35 volts so that it has to be kept short as adjusted. The little wire arrangement with the knob is to pull down the lever when the case is on the lamp. I have not sent the brass case nor the globe, but these little lamps have been designed to go in confined spaces, and with the 75 volt incandescent circuits are worked two in series, and they look very neat when in their places. In a few days I hope to send the ordinary 2000 candle power lamp which has no glycerine dashpot. These work with solenoids and long open arc and if anything are a trifle simpler than that already sent. I never thought about sending the little lamp before or should have done so. The 2000 c.p. lamps have been made very clumsily but I will test one and send it without delay. ## I have also been busy with installations buy things are very quiet here as a rule. ## The lamp has been in use as you will see, and is not newly made."





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