Romeo. How is't, my soul? let's talk, it is not day.
Jul. It is, it is; hie hence, be gone, away!
It is the lark that sings so out of tune,
Straining harsh discords, and unpleasing sharps.
Some say, the lark makes sweet division;
This doth not so, for she divideth us.
Juliet evidently agrees with Portia that 'nothing is good without respect.' The lark heralds the dawn, so Romeo must leave her, ergo, the lark sings 'out of tune,' his strains are full of 'discords' and 'sharps.' The last two lines contain an interesting allusion in the word 'division,' besides the pun on 'she divideth us.'
'Division' means roughly, a brilliant passage, of short notes, which is founded essentially on a much simpler passage of longer notes. A cant term for the old-fashioned variation (e.g., the variations of the 'Harmonious Blacksmith') was 'Note-splitting,' which at once explains itself, and the older word 'Division.' A very clear example of Divisions may be found in 'Rejoice greatly' in the Messiah. The long 'runs' on the second syllable of 'Rejoice,' consisting of several groups of four semiquavers, are simply 'division' or 'note-splittings' of the first note of each group.
The word, however, has a further use, namely, to play 'divisions' on a viol-da-gamba. This was a favourite accomplishment of gentlemen in the 16th and 17th centuries. Sir Andrew Aguecheek numbered this amongst his attainments, (see Twelfth Night I, iii, 24); and readers of John Inglesant will remember that 'Mr Inglesant, being pressed to oblige the company, played a descant upon a ground bass in the Italian manner.' Playing a descant on a ground bass meant playing extempore 'divisions' or variations, to the harmony of a 'ground bass' which (with its proper chords) was repeated again and again by the harpsichordist, until the viol player had exhausted his capacity to produce further 'breakings' of the harmony.
In 1665 there was published an instruction book in this art, called Chelys Minuritionum, i.e., the 'Tortoise-shell of Diminutions,' hence (Chelys meaning a lyre, made of a tortoise-shell) 'The Division Viol.' The book is by Christopher Sympson, a Royalist soldier, who was a well-known viol-da-gamba player. The work is in three parts, the third of which is devoted to the method of ordering division on a ground.
'Diminution or division to a ground, is the breaking either of the bass or of any higher part that is applicable thereto. The manner of expressing it is thus:—
'A ground, subject, or bass, call it what you please, is prick'd down in two several papers; one for him who is to play the ground upon an organ, harpsichord, or what other instrument may be apt for that purpose; the other for him that plays upon the viol, who having the said ground before his eyes as his theme or subject, plays such variety of descant or division in concordance thereto as his skill and present invention do then suggest unto him.'
[See the [Appendix] for an example by Sympson.]
Further on, he distinguishes between 'breaking the notes of the ground' and 'descanting upon' the ground.