1835.] 



Observations on Visible Vibration. 



437 



other fluids, the neutralization only decreases from the 

 surface of the fluid downwards ; so that, in order to obtain 

 the same number of notes from water as from mercury, 

 it would be necessary to employ a glass about three times 

 as high. 



58. Before I proceed further it maybe necessary to state 

 my method of conducting these experiments. The same 

 graduated glass (51.) was employed throughout, fixed on a 

 level plane, and the results, generally speaking, noyaken 

 until the glass yielded the descending notes sympathetically 

 responsive to a flute. The glass was carefully washed, and 

 wiped dry at the end of each experiment, and the specific 

 gravity of each fluid was taken immediately before it was 

 employed. I have gone twice over these and the two pre- 

 vious (55, 56.) experiments. In the first trial my pupil, Mr. 

 Whitchurch, sounded the flute, and in the second, Mr. Ayl- 

 ward, a professor of that instrument, a gentleman on whose 

 correct musical ear I can implicitly rely. 



59. The following liquids were successively employed in 

 the order of their specific gravities, as follows : — 



Sp. Gr. . 



1. Sulphuric acid . . . 1*852 



