SPEAKING AND SINGING HEADS. 225 



thunder. In the palace of the Persian king, however, a 

 more artificial imitation is likely to have been employed, 

 and it is not improbable that the method used in our 

 modern theatres was known to the ancients. A thin 

 sheet of iron, three or four feet long, such as that used 

 for German stoves, is held by one corner between the 

 finger and the thumb, and allowed to hang freely by its 

 own weight. The hand is then moved or shaken hori- 

 zontally, so as to agitate the corner in a direction at right 

 angles to the surface of the sheet. By this simple process 

 a great variety of sounds will be produced, varying from 

 the deep growl of distant thunder to those loud and 

 explosive bursts which rattle in quick succession from 

 clouds immediately over our heads. The operator soon 

 acquires great power over this instrument, so as to be 

 able to produce from it any intensity and character of 

 sound that may be required. The same effect may be 

 produced by sheets of tin plate, and by thin plates of 

 mica ; but on account of their small size, the sound is 

 shorter and more acute. In modern exhibitions an admi- 

 rable imitation of lightning is produced by throwing the 

 powder of rosin, or the dust of lycopodium, through a flame, 

 and the rattling showers of rain which accompany these 

 meteors are well imitated by a well-regulated shower of 

 peas. 



The principal pieces of acoustic mechanism used by 

 the ancients were speaking or singing heads, which were con- 

 structed for the purpose of representing the gods, or of 

 uttering oracular responses. Among these, the speaking 

 head of Orpheus, which uttered its responses at Lesbos, 

 is one of the most famous. It was celebrated not only 

 throughout Greece, but even in Persia, and it had the 

 credit of predicting, in the equivocal language of the 

 heathen oracles, the bloody death which terminated the 

 expedition of Cyrus the Great into Scythia. Odin, the 



