US524172A - Variable-resistance medium for telephones - Google Patents

Variable-resistance medium for telephones Download PDF

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Publication number
US524172A
US524172A US524172DA US524172A US 524172 A US524172 A US 524172A US 524172D A US524172D A US 524172DA US 524172 A US524172 A US 524172A
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Prior art keywords
variable
telephones
resistance medium
william
boron
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    • CCHEMISTRY; METALLURGY
    • C01INORGANIC CHEMISTRY
    • C01BNON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B35/00Boron; Compounds thereof
    • C01B35/02Boron; Borides
    • C01B35/023Boron

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Battery Electrode And Active Subsutance (AREA)

Description

.UNITED'USTATES. PATENT OFFICE.
WILLIAM W. JACQUES, OF NEWTON, ASSIGNOR 'ro THE AMERICAN BELL TELEPHONE COMPANY, OF BOSTON, MASSACHUSETTS.
VARIABLE-RESlSTA NCE MEDIUM FOR TELEPHONE'S.
SPECIFICATION forming part of Letters Patent No. 524,172, dated August '7, 1894. I Application filed May 14, 1894:. Serial No. 511,239. (No specimens.)
Toall whom it may concern:
Be it known that 1, WILLIAM W. JACQUES, of'Newton, in the State of Massachusetts,have invented a new and useful Variable-Resistance Medium for Use between the Electrodes of Battery-Telephone Transmitters, of which 7 The'process consists in reducing a salt of boron by heating it with sodium or potassium and again heating the product .to a white heat in the absence of air..-
I take boracic acid and fuse it at-a white heat until it assumes the appearance of agate. I
then .pulverize it and mix it with metallic sodium or potassium in proper proportions to reduce the boracic acid. The mixture is then heated in a closed vessel, care being taken to prevent the access of air. After cooling, the
mixture is dissolved in water and filtered,
thus producing amorphous boron. This when dried at a reddish white heat in the absence of air produces electric and microphonic boron in granular condition. The grains form an ex- 2. The herein described process of producing a variable resistance medium for battery telephones consisting in reducing a salt of boron by heating it with sodium or potassium, and againheating the product to a white heat in the absence of air.
Witnesses:
WILLIAM W. SWAN, WILLIAM SUL IVAN.
WILLIAM W. JACQUES.
US524172D Variable-resistance medium for telephones Expired - Lifetime US524172A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2697136A (en) * 1951-04-28 1954-12-14 Bell Telephone Labor Inc Microphone and microphone granules
US2956862A (en) * 1956-06-01 1960-10-18 Nat Distillers Chem Corp Process for reduction of chemical compounds

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2697136A (en) * 1951-04-28 1954-12-14 Bell Telephone Labor Inc Microphone and microphone granules
US2956862A (en) * 1956-06-01 1960-10-18 Nat Distillers Chem Corp Process for reduction of chemical compounds

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