100 NATURAL HISTORY. 



lity or interchange of the medium will not produce 

 an inequality of sound ; as if three bells were made 

 one within another, and air betwixt each ; and then 

 the uttermost bell were chimed with a hammer, how 

 the sound would differ from a simple bell. So like 

 wise take a plate of brass, and a plank of wood, and 

 join them close together, and knock upon one of 

 them, and see if they do not give an unequal sound. 

 So make two or three partitions of wood in a hogs 

 head, with holes or knots in them ; and mark the 

 difference of their sound from the sound of an hogs 

 head without such partitions. 



Experiments in consort touching the more treble, and 

 the more base tones, or musical sounds. 



178. It is evident, that the percussion of the 

 greater quantity of air causeth the baser sound ; and 

 the less quantity the more treble sound. The per 

 cussion of the greater quantity of air is produced by 

 the greatness of the body percussing ; by the lati 

 tude of the concave by which the sound passeth ; and 

 by the longitude of the same concave. Therefore 

 we see that a base string is greater than a treble ; 

 a base pipe hath a greater bore than a treble ; and 

 in pipes, and the like, the lower the note-holes be, 

 and the further off from the mouth of the pipe, the 

 more base sound they yield ; and the nearer the 

 mouth, the more treble. Nay more, if you strike 

 an entire body, as an andiron of brass, at the top, it 

 maketh a more treble sound ; and at the bottom a 

 baser. 



