CHAP. II.] 



MUSICAL INSTRUMENTS. 



121 



plates at the nodal lines corresponding to the fundamental note of 

 each of them. The notes are struck with a kind of hammer with a 

 cork head. The notes have a very pure clear tone. The negroes' 

 castanets are harmonicas in which wood replaces glass and which 

 has no sounding-box. Lastly, metal plates arranged in the, same 

 manner as in the glass harmonica, and struck alternately or simul- 

 taneously with a hammer moved by a keyboard, form a sort of 

 carillon. 



Instruments of this class are of very early origin and found in 

 almost all nations ; generally they are perfected by the addition of 

 resonance globes or tubes, the air in each according in vibration 

 with the note of the slab of wood or plate of metal suspended 



FK; 71. Harmonica with plates of glass. 



above them. Hollow gourds and pumpkins are chosen for globes 

 and tubes, in sizes forming a series. The " Gender " of the Javanese 

 is a notable representative of the kind possessing bars of sonorous 

 metal. 



The name of Musical-Box is given to automatic instruments in 

 which the notes are produced by small plates of steel or copper 

 arranged like the teeth of a comb ; the dimensions of these plates 

 are calculated so as to give the notes of the scale with their acci- 

 dentals. The teeth are struck by small pins set round a cylinder, 

 which is moved at a uniform rate by clockwork. The box in which 

 this mechanism is inclosed gives more power and sonorousness to 

 the notes emitted by these plates. The sonorousness is still more 



