Siemens & Halske 

 Precision Instruments 



Epstein Apparatus for Iron Testing 



We offer a varied line of Precision Electrical Measuring Instruments suit- 

 able for Universities, Colleges, Technical Schools, Public Service Companies, 

 Industrial Factories, Consulting Engineers, etc. 



Among our important specialties are : Laboratory and Portable Ammeters, 

 Voltmeters and Wattmeters ; Current and Potential Transformers ; High 

 Range Electrostatic Voltmeters ; Galvanometers of many Types ; Potenti- 

 ometers, Resistance Standards, Wheatstone Bridges, etc., Oscillographs ; Self- 

 induction Apparatus ; Precision Mica Condensers ; Iron-Testing Apparatus ; 

 Insulation Testing Outfits ; Frahm Frequency Meters and Tachometers ; Pho- 

 tometers ; Adjustable Laboratory Rheostats. 



We maintain a Permanent Exhibit of Siemens & Halske instruments 

 which should be visited by all engineers who are interested in the subject. 



All Siemens and Halske instruments can be repaired and calibrated, in 

 their Repair Department, 90 West Street, New York. 



Write for Catalogues 



James G. Biddle 



Sole Agent for United States 

 1211 Arch Street Philadelphia, Pa. 



