752 Electrical and other Properties of Sand. [Feb. 11. 



number of notes may be obtained. So far I have succeeded in pro- 

 ducing only five with any decree of certainty — one note being, in 

 fact, obtained by damping the vibrations of the largest tube. The 

 sound is hardly pleasant, but nevertheless I venture to play, if I can, 

 a simple tune upon what may perhaps be called the sand-organ. 



[C. E. S. P.] 



