Vol. 33. JANUARY 1867. No. 220. 



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N° 220.—JANUAEY 1867. 



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Illustrative of Dr. A. Topler's Paper on the Application of the Principle 

 of Stroboscopic Disks to the Optical Analysis of Vibrating Bodies, and 

 Dr. Neumann's on an Apparatus for directly measuring the Velocity 

 of Sound in the Atmosphere. 



iyg~ With this, the regular Number for January 1867, is published, and 

 should be delivered to Subscribers, the Supplement (No. 219) to 

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