148 ' ELEMENTARY PROPERTIES 



terate the quality of the thing received. If we 

 extend our views to air and light, we shall find 

 that, although each of these bodies possesses 

 properties of its own, which are Inseparable 

 from the extension which they contain, that 

 they are, nevertheless, originally destitute 6f a 

 variety of thos^ secondary qualities which are 

 'often ascribed to them, but which they after- 

 wards factitiously obtain. With respect to 

 fcir, it bears the same relation to sound, that 

 water does to flavor ; or that the block does 

 to figure ; if air possessed any particular 

 ^sound of its own, that sound, like the figure 

 upon the canvas, would constantly manifest 

 itself; either, when it was impelled by mecha- 

 nical means through musical instruments in 

 general, or, through the vocal organs in parti- 

 cular ; instead of harmony, discord must be 

 produced. Air possessing, however, the pri- 

 mary and essential attributes of expansibility 

 Blone, it has the power to expand, and the 

 capacity to be compressed ; to be modulated 

 atid harmonised by the energy resident in the 

 Organs of speech ; and, by their instrumentality 

 language is produced. The satne observations 

 equally apply with respect to resistance. If the 

 medium of air, through which the rays cf light 

 are conveyed, instead of being diaphanous 

 and permeable, were turbid and colored ; the 

 rays of light, instead of being transmitted, 



