. Collection of United States patents granted to Thomas A. Edison, 1869-1884 . before described. The lamp can be disconnected from thepump, as will be readily understood, by seal-ing off the tube F, and the vacuum will be 50maintained within the lamp by the ground-glass union or joint at the junction of the globeand base. What I claim is— 1. The method of preparing carbons for in- 55candescing electric lamps having broad or en-larged ends, consisting in first carbonizing thefilament, converting its body into carbon, andthen subjecting the broad ends or enlargedportions to the action of heat in
. Collection of United States patents granted to Thomas A. Edison, 1869-1884 . before described. The lamp can be disconnected from thepump, as will be readily understood, by seal-ing off the tube F, and the vacuum will be 50maintained within the lamp by the ground-glass union or joint at the junction of the globeand base. What I claim is— 1. The method of preparing carbons for in- 55candescing electric lamps having broad or en-larged ends, consisting in first carbonizing thefilament, converting its body into carbon, andthen subjecting the broad ends or enlargedportions to the action of heat in vacuo, sab- as set forth. 2. The combination of a vacuum-chamber,a platform therein for the carbons, an ex-hausting apparatus, and means for impartinga high heat to the broad ends of the carbons 65while in vacuo, substantially as shown anddescribed. This specification signed and witnessed this15th day of June, 1880. THOMAS A. ED1SOX. Witnesses: S. L. Griffin,Wm. Carman. r (No Model.) T. A, EDISON. DYNAMO ELECTRIC MACHINE. No. 298,954. Patented May 20,
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Keywords: ., boo, bookcentury1800, booksubjectinventions, booksubjecttelephone
