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bodies are also vehicles of sound; many experiments are mentioned by 

 Kircher and others on the communication of sound through solid 

 bodies, such as masts, yards, and other long beams of dry substances 

 with similar results. Dr. Monro has published a particular account of 

 very curious experiments on the propagation of sound through water, 

 in his dissertation on the physiology of fishes; so it now appears that air 

 is by no means the only vehicle of sound. In 1760, Cotunni published 

 his important discovery that the labyrinth or inmost cavity of the ear 

 in animals is completely filled with water. This after some contest, 

 has been completely demonstrated, and admitted by all. Place a 

 small bell under water in a large glass vessel, and strike it, the sound 

 will be heard as if the bell had been struck on the vessel's side. 

 The manner in which the nerve of the ear is exposed to the vibration 

 of sound is uncertain, and has long occupied the eminent anatomists 

 of Europe. The descriptions that have been given by Comparette, 

 Scarpa, Monro, Camper, and many others are replete with singular 

 discoveries and valuable information. 



By the experiment of some philosophers it has been found that 

 sound travels at the rate of 1142 feet in a second, about thirteen 

 miles in a minute; its progress is the same even against the wind, ex- 

 cept that its velocity is diminished. Its progress can be readily cal- 

 culated; for instance, measure a certain distance between two points, 

 and let a gun be fired at one end, and the interval between the flash 

 and the report will give the precise time the sound required to travel 

 the distance. If you observe a flash of lightning, and desire to know 

 how far the cloud is from you, time the number of seconds between 

 the lightning and the following report of thunder, and allow 1142 

 feet for each second. " Derham has proved by experiment that all 

 sounds travel precisely at the same rate. The sound of a gun and 

 the striking of a hammer are equally swift in their motions; the soft- 

 est whisper flies as swiftly, as far as it goes, as the loudest thunder. 

 The strength of sound is greatest in cold air, and least in warm. The 

 whispering gallery is constructed on the principle that after it has been 

 reflected from difierent places may be brought together in one point, 

 will be more audiblethere than even at the place from whence it pro- 

 ceeded. An echo is a reflection of sound striking against some ob- 

 ject. There is a most extraordinary echo at a fortress near Louvain, 

 in Flanders. If a person sang, he heard his own voice only, without 

 any repetition ; whereas those who stood at a distance, heard the 



