[D8930AAX], Letter from David Trumbull Marshall to John Kruesi, June 4th, 1889


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[D8930AAX], Letter from David Trumbull Marshall to John Kruesi, June 4th, 1889

Editor's Notes

We send you today several samples of insullative (XXXX?). This (couprocessed?) you can supply for 30 cents per lbs if it is desirable to mixsome insuert sub-stored with it, that of course will make it less per lb. The specific quantity of this compound is 3 to 3.5; copper being 8.95. We also send some samples of mine. It will not be necessary to repost our wire unless it is suitable wire sample #604 in as so far very carefully tested here and shows a perfect insulation after being kept in wet waste at as effecival pressure of 110 volts for 60 hours. It has been kept at a temperature of 210F for 25 days; it starts will flame in the least where subjected to a current of 100 amperes till destroyed. The wire which these samples of insulation were put, were supposed to be fairly well insulated to begin with, so if slight cracks occur in the fireproof compound it is hoped it will not render the wire useless. The black point our #579 is, we think something new. We will send a few more samples of wires in a short time.





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