21 



K 



ELECTRICITY. 



In Charge of G. F. Sever. 



1. Historical Collection of Incandescent Lamps, show- 



ing the development of the lamp and its component parts, 

 from the first crude forms to the present 220 volt, high 

 efficiency lamps. Exhibited by M. K. Eyre. 



2. Thomson 14" Spark Inductorium, Crookes Tubes and 



Fluoroscopes, as made by the General Electric Co. 

 Exhibited by W. H. Meadowcroft. 



This collection illustrates the more recent develop- 

 ments in the apparatus as applied to the generation and 

 utilization of Rontgen rays. 



3. Enclosed Arc Lamps. Exhibited by the Electric Arc 



Light Co. 



This type of lamp has become an interesting feature 

 of both the scientific and engineering world. The ex- 

 hibit shows the various parts of the regulating mechan- 

 ism and the lamps in actual operation. 



4. Apparatus Illustrative of the Jacques Carbon Bat- 



tery. Also batteries showing the generation of electri- 

 cal energy from carbon without the application of heat. 

 Used by Mr. W. E. Case in lecture experiments and ex- 

 hibited by the Electrical Engineering Department, Co- 

 lumbia University, 



This latter apparatus shows that it is possible to gen- 

 erate electrical energy from carbon without the applica- 

 tion of heat, as is done in the Jacques battery. 



5. Apparatus for Obtaining the Maximum Value of a Direct 



Current in any Circuit and the Time Elapsing Be- 

 tween the Make and Break of the Circuit. Exhib- 

 ited by C. M. Clark and C. W. MacMullen, senior 

 students in Electrical Engineering, Columbia University. 



