[ 2 7 * ] 
Lychanos Mefon , were called Mobiles , becaufe they 
varied according to the different Species and Varie- 
ties of Muftc. 
I come now to determine the Qucdion, What thefe 
different Genera and Species were. You know, that 
by Genus and Species was underftood a Divifion of 
the Hiatejfaron , containing four Sounds, into three 
Intervals. The Greeks conftituted three* Genera , 
known by the Names of enharmonic , chromatic , and 
diatonic . The chromatic was fubdivided into three 
Species, and the diatonic into two. The three chro- 
matic Species were the Chromaticum molle , the 
Sefo[uialtenim> and the Toni atm . The two diatonic 
Species were the 'Diatonicum molle , and the Inten- 
fum fo that they had fix Species in all. Some of 
thefe are in Ufe among the Moderns, but others are 
as yet unknown in Theory or Practice. 
I now proceed to define all thefe Species, by de- 
termining the Intervals, of which they feverally con- 
fided 5 beginning by the Diatonicum intenfum , as the 
mod eafy and familiar. 
The TDiatonicum intenfum was compofed of two 
Tones, and a Semitone: But, to fpeak exaftly, it 
confids of a Semitone Major , a Tone Minor , and 
a Tone Major. This is in daily Practice; and we 
find it accurately defined by Hidymus , in Ptolemy % 
Harmonics publifhed by Dr. Wallis. 
The next Species is the Diatonicum molle , as yet 
undifeovered, as far as appears to me, by any modem 
Author. Its component Intervals are, the Semitone 
Major , an Interval compofed of two Semitones A//- 
nor } and the Complement of thefe two to the fourth, 
being 
M m 
