250 



Note on an Experiment by Chlaclni. [Apr. 16, 



rated from the sand, and performs its evolutions within the numerous 

 centres of vibration into which the plate breaks up. 



With respect to the double circles (figs. 18 and 19), and the double 

 ellipse (fig. 16), Chladni remarks that these are the most difficult of 

 all the figures to produce. With the two powders, sand and lyco- 

 podium, the difficulty ceases, the lighter powder forming the outer 

 and the sand the inner ring. 



The figures represented have been faithfully copied from the plates ; 

 such distortions as those represented in fig. 10 are due to irregulari- 

 ties in the structure of the plate. 



DESCRIPTION OF THE PLATE. 



jNo. 01 



Material 



Dimensions. 



Eigure. 



oi tne plate. 



1. 



Brass. 



12 in., x 12 in. 



2. 





j> 



3. 







4. 





33 



5. 







6. 



Bronze. 



8 in. x 8 in. 



7. 



Brass. 



("Major axis, 7 in. \ 

 \ Minor axis, 5 in. J 



8. 



White metal. 



33 



9. 



7 in. x 7 in. 



10. 



Bell metal. 



35 



11. 



Brass. 



33 



12. 



j) 



8 in. x 8 in. 



13. 



)> 



7 in. external diameter. 



14. 



3) 



33 



15. 



3) 



33 



16. 





("Major axis, 7 in. \ 





\ Minor axis, 5 in. j 



17. 



33 



8 in. x 4| in. 



18. 



Glass. 



8 in. diameter. 



19. 



33 



9 in. diameter. 



20. 



3 3 



Bell metal. 



33 



21. 



7 in. x 7 in. 



Materials employed. 



Sand and lycopodium. 



)S 33 



Sulplmr. 



3 3 3 3 



Sulphur and lycopodimn. 



33 33 



Sand and lycopodium. 



Sand and sulphur. 

 Sand and lycopodium. 



Note. — When the plate is clamped near the edge, the bow should be applied as 

 near to the clamp as may be convenient. If far removed therefrom, the amplitude 

 of the vibrations is too great to produce a good figure, and glass plates are liable to 

 be broken. 



