cir. xxx. 



CPILADNfS SAND-FIGURES. 



273 



reach our ear. The number of sand-rays may be increased 

 on round plates Jby placing the fingers on different points, 

 and checking the vibrations, see Fig. 53. When Chladni 

 had made many of these, and worked out their relation to 

 the particular note sounded, he went on to experiment on 



FIG. 53. 



square plates, and produced the curious figures given in 

 Fig. 54, and many others much more complicated. The first 

 of these figures he got by fixing the plate by its centre and 



FIG. 



drawing the bow across one of the corners ; the second 

 by drawing it across the middle of one of the sides ; and 

 the more complicated figures below by placing the finger 

 and thumb on various points so as to form artificial nodes. 

 The lines of sand on these plates are formed on the same 



