Andreas Ornithoparcus his Micrologus, or Introduction: containing the art of singing Digested into foure bookes. Not onely profitable, but also necessary for all that are studious of musicke. Also the dimension and perfect vse of the monochord, according to Guido Aretinus. By Iohn Douland lutenist, lute-player, and Bachelor of Musicke in both the Vniuersities. 1609.

Rules of Alteration.

FIrst, There be foure Notes, which may be altered, (saith Franchinus lib. 2. cap. 13.) a Long, a Breefe, a Semibreefe, and a Minime.

2 Alteration doth exclude the Larg, and is limitted by a Minime, be∣cause a Larg hath not a greater than it selfe, whose neighbouring part it may be: and the lesse figures are not to be reckoned after the number of three.

3 Alteration happens in numbers which be not perfect, but are parts neighbouring to perfect Notes, because a perfect Note in as much as it is a perfect Note is not lyable to Alteration.

4 Onely the Notes are altered, not the Rests.

5 Alteration falleth vpon the second Note, not vpon the first.

6 Euery altered Note containeth it selfe twise.

7 A like Note is not altered before a like Note.

8 Alteration onely fals out in perfect degrees.

9 Alteration comes for want of one Note, when you haue reckoned af∣ter the Ternary numbring.

10 As oft as two alterable Notes are placed betwixt two imperfectible Notes without a Pricke of Diuision: the second is alwayes altered, as the Example following doth shew. 〈♫〉〈♫〉 Altera. Tenor. Altera. 〈♫〉〈♫〉 Base.

11 If a Rest together with the figure, to which it is of equall value, be enclosed betwixt 2. perfect notes; thē either the rest goes before the figure, or followesit; if the Rest go before, the figure is altered: if otherwise, there is no place for Alteration, because the notes only are altered, & not the Rests. Be∣side Alteration fals alwayes vpon the second, and not vpon the first, thus: 〈♫〉〈♫〉 Tenor. 〈♫〉〈♫〉 Base.

12 Alteration is taken away by the fulnesse of the notes; and by the Pricke of Diuision. In Ligatures also Alteration is kept, as in the following Example is cleere. 〈♫〉〈♫〉 Tenor. 〈♫〉〈♫〉 Base.

13 As oft as three alterable Notes are shut within two imperfectible

Notes, both the imperfectible shal remaine perfect, and none of the altera∣ble Notes is altered: because the Ternarie number is euery where perfect.