■Experiments and Inquiries refpeBlng Sound and Light, 



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Table XI. 



A, is the length of the pipe from the lateral orifice to the end. C, the prefliire at ' 

 which the found began. B, its termination, by leflening the preflure; D, by increafing 

 it. E, the note anfwcring to the firft found of each pipe, according to the German 

 method of notation. F, the number Ihowing the place of each note in the regular feries 

 of harmonics. The diameter of the pipe was .35 > the air dufl: of the mouth-piece 

 meafured, where fmalleft, .25 by .035 ; the lateral orifice .25 by .125. The apparatus was 

 rot calculated to apply a preflure of above 22 inches. Where no number ftands under C, 

 a fudden blafl: was required to produce the note. 



IX. Of the Vibrations, of different elaftic Fiuids. 

 All the methods of finding the velocity of found, agree in determining It to be, iii ^ 

 fluids of a given elafticity, reciprocally in the fubduplicate ratio of the denfity : hence, in 

 pure hydrogen gas it fbould be v^i3ZZ3.6 times as great as in common airj and the pitch 

 of a pipe fliould be a minor fourteenth higher in this fluid than in the comtaon air. It i» - 



therefore - 



