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Source of Light for Optical Bench 



No. 4232 No. 3232 No. 3680 A No. 3627 No. 3646 No. 3667 No. 3644 



BED KOD END SUPPORT SOURCE OF LIGHT CLAMP PHOTOMETER ROTATING LAMP PLATFORM 



No. 3680A. SOURCE OF LIGHT for Ojitical Bench, Gives parallel rays 



for measuring focal length of lens. 



MAINTAINS UNIFORM INTENSITY for photometer experiments. 



ATTACHES TO ANY LAMP SOCKET either A. C. or D. C. 



NO ADJUSTING as with arc lamp. 



MORE INTENSE than candles. 



SHIELDED so as not to illuminate a dark room. 



VERY USEFUL also in lecture and demonstration work for producing a 

 portable, adjustable and intense beam of lig'ht. 



Write for price 



Ask for information on other new designs of Recent Developments in 

 Scientific Appeiratus. 



W. M. Welch Scientific Company 



Manufacturers, Exporters and Importers of Scientific Apparatus and Supplies 



1516 Orleans Street Chicago, 111., U.S.A. 



