On the Variety of Voices. 65 
that is graver, and one that is acuter than the rest. 
The relative affections of these combinations, or the 
mutual ratios of their constituent imperfect unisons, 
may be varied indefinitely even in instruments or 
vocal organs of the same description, from the 
numberless slight variations that take place of ne- 
cessity in the elasticity and tension of their respec- 
tive similar parts; the obvious consequence of which 
is, that the cycles of their joint beats or pulses will 
be diversified in a manner equally unlimited. Now 
it is very well known, that the different sensations 
produced by several musical intervals, arise from 
the comparative properties of their respective cycles: 
but what is proved of larger intervals will hold good 
in respect to smaller; and is equally applicable to 
their effects on the ear, which are therefore shewn 
to be susceptible of unlimited modifications in the 
common course of things. The conclusions that 
have already appeared in this paper, may incline the 
reader to imagine, that cither the theory is false, or 
music isa very imperfect art; because, according 
to the preceding scheme, our ideas of symphony 
and harmony result from sensations excited by the 
use of small intervals, constantly substituted in the 
room of elementary sounds, of which our only 
knowledge seems to be that they exist, but are never 
perceived alone, or uncombined with others of the ° 
same kind. To this plausible objection, the following 
answer (grounded on observation and experience) 
VOL, V. I 
