you begirt wifh C, the flat 3d, the femitones 
will occur in, the fame order as in the firfl 
modus. You will obferve that any of thefe 
notes or half-notes, on the harpfichord, may 
be made the fundamental or firft note of 
the fcale in either modus , which note gives 
name to the key in which you modulate* 
and with which you muft neceffarily con- 
elude the piece: But whatfoever note you 
make the key-note, the femitone-intervals 
muft fall in their proper places ; and this 
can be attended with no difficulty, as the 
inftrument confifts entirely of femitones. 
But, before we try the experiment, it is ne- 
ceflary you fhould know, that every femi-* 
tone takes, occafionally, either the name of 
the note above or of that below it: thus, 
this half note between G and A is GJharp, 
that is, half a tone higher than the natural 
Gj or it is Ajlat, that is, half a tone lower 
than the natural A. 
. If now you begin with C, and proceed 
upwards, note by note, you find the femi- 
tone-intervals lie in their proper places, 
namely, between the 3d and 4th, and be- 
tween the yth and 8th, without the necef- 
fity of introducing any of the fliort black 
keys. But if you now make D your fun- 
damental 
