RECORDS OF MEETINGS. 357 



however, an exceedingly brittle metal and hence apparently 

 entirely unsuited for use as the filament of an incandescent lamp. 



"Attempts were made however, by various persons abroad and 

 in this country, Dr. Coolidge among them. Their efforts resulted 

 in the production of a filament of tungsten made however, by a 

 paste process giving a filament which stood the action of the current 

 and produced a very white light with a remarkable economy of 

 electrical power. This filament however, was very fragile so that 

 it was difficult to transport such lamps without breaking them and 

 even moderate jarring in the case of the already installed lamps 

 oftentimes destroyed it. It was also impossible accurately to 

 adjust individual lamps to a particular voltage. 



" It was to remedy these difficulties that Dr. Coolidge, working 

 in the Research Laboratory of the General Electric Co. at Schenec- 

 tady, bent his energies. 



"He had observed in some experiments that under certain cir- 

 cumstances, the brittle tungsten was so altered as to show some 

 signs of becoming ductile and by a long continued and tedius series 

 of experiments, in which the tungsten was heated and mechanically 

 treated, he was finally able to devise a process by which this 

 typically brittle metal could be rendered ductile so that it could be 

 drawn into a wire of any length and fineness desired. A wire 

 thus made was found to be admirably suited for the purpose of the 

 filament of an incandescent lamp. It could be run at a very high 

 temperature, thus giving a very white light and securing high 

 efficiency. It was not fragile so that no difficulty existed on this 

 score. It could be produced of uniform length and section so that 

 the individual lamps could all be adjusted to run at any desired 

 voltage. The result of this invention was the immediate and 

 universal introduction of the tungsten lamp which we now see 

 everywhere. 



' Various other applications of mechanically treated tungsten 

 have been made. Thus it furnishes a reliable and comparatively 

 inexpensive material for use as the electrodes of the spark appara- 

 tus of automobiles, and also for use as the target in X-Ray tubes. 

 " Dr. Coolidge has produced a greatly improved form of X-Ray 

 tube in which both the cathode and the target are of tungsten. 

 Most important however, in the tube is the manner in which the 



