136 



THE APPLICATIONS OF PHYSICAL FORCES. [BOOK n. 



over one of its sides. The harp used by David must have been a 

 portable instrument, as he danced at the same time that he pla} 7 ed 

 and sung. 



The lyres or citharae of the ancient Greeks were instruments 

 similar to those of the Jews. Four, five, seven, nine, or more 

 stretched strings, communicating their vibrations to the supports and 

 cases, which took various forms, of which they were constructed, then 

 to the masses of air inclosed in them ; such were the instruments 

 which were chiefly used to accompany the voices of rhapodists or 

 poets. The strings were pulled with the fingers or struck with the 



FIG. 92. The kimior. 



FIG. 0:i The harp of the Hebrews. 



plectrum, a rod of ivory or polished wood which the performer held 

 in his right hand. 



Who was the inventor of the lyre 2 According to the ancients, 

 Mercury or Apollo, for they could not imagine that too noble an 

 origin could be given to such an enchanting art as music. Had not 

 Orpheus, by playing on the lyre, tamed wild beasts, moved trees and 

 rocks into tears, won over Cerberus, and touched even inexorable 

 Pluto, when he dragged Eurydice to the infernal regions ? 



But we will here leave fable, however ingenious and touching it 



