48 
APPENDIX, VI. 
of those instruments, which contain even the 
greatest Compass. 
I have before said, that our ideas of a voice, 
or instrument, being perfectly in tune or not, 
arise from comparing it with the musical inter- 
vals to which we are most accustomed. 
As the upper and lower parts of every instru- 
ment, however, are but seldom used, we are not 
so well acquainted with the intervals in the 
highest and lowest octaves, as we are with those 
which are more central; and for this reason 
the harpsichord-tuners find it more difficult to 
tune these extreme parts. 
As a bird’s pitch, therefore, is higher than — 
that of an instrument, we are consequently at a 
still greater loss when we attempt to mark their 
notes in musical characters, which we can so 
readily apply to such as we can distinguish 
with precision: 
The third, however, and unsurmountable dif- 
ficulty is, that the intervals used by birds are 
commonly so minute, that we cannot judge at 
all of them from the more gross intervals into 
which we divide our musical octave. 
It should therefore be recollected, by those 
who have contended that the Greeks and Ro- 
mans were acquainted with such more minute 
