8 



Lord Kayleigh on Bells. 



when the blow is delivered about midway between the crown 

 and rim of the bell than at other places. 



The next tone is c". Observation showed that for this 

 vibration also there are four, and but four, nodal meridians. 

 But now there is a well-defined nodal circle of latitude, 

 situated about a quarter of the way up from the rim towards 

 the crown. As heard with the resonator, this tone disappears 

 wdien the blow is accurately delivered at some point of this 

 circle, but revives with a very small displacement on either 

 side. The nodal circle and the four meridians divide the 

 surface into segments, over each of which the normal motion 

 is of one sign. 



To the tone /" correspond 6 nodal meridians. There is no 

 well-defined nodal circle. The sound is indeed very faint, when 

 the tap is much removed from the sound-bow ; it was thought 

 to fall to a minimum when the tap was about halfway up. 



The three graver tones are heard loudly from the sound- 

 bow. But the next in order, Z/'t>, is there scarcely audible, 

 unless the blow be delivered to the rim itself in a tangential 

 direction. The maximum effect occurs at about halfway up. 

 Tapping round the circle, we find that there are 6 nodal 

 meridians. 



The fifth tone, d in , is heard loudly from the sound-bow, but 

 soon falls off when the locality of the blow T is varied, aud in 

 the upper three fourths of the bell it is very faint. No 

 distinct circular node could be detected. Tapping round the 

 circumference showed that there were here 8 nodal meridians. 



The highest tone recorded, /"', was not easy of observation, 

 and I did not succeed in satisfying myself as to the character 

 of the vibration. The tone was perhaps best heard when 

 the blow was delivered at a point a little below the crown. 



All the above tones, except /", were tolerably close in pitch 

 to the corresponding notes of the harmonium. 



Although the above results seemed perfectly unambiguous, 

 I was glad to have an opportunity of confirming them by ex- 

 amination of another bell, This was afforded by a loan of a 

 bell cast by Taylor, of Loughborough, and destined for the 

 church of Ampton, Suffolk, where it now hangs. Its weight 

 is somewhat less than 4 cwt., and the nominal pitch is d. 

 The observations were entirely confirmatory of the results 

 obtained from Messrs. Mears's bell. The tones were 



d" ! 



9 



m . 



<!\>-2, d»-6, /" + 4, W\>—W, 

 (4) (4) (6) (6) (8) 



the correspondence between the order of the tone and the 

 number of nodal meridians being as before. In the case of 

 d" there was the same well-defined nodal circle. The highest 



