It was intended for the Sake of Variety. When the Ear begins to be surfeited with too much of the _Cantilenam eandem Canis_, as Terence expresses it, then Contrivances are made, without infringing upon the Laws of Harmony, to have the Burthen of the Song upon a different Note; not that this Key is to differ from the former in it's Mensurations from one Note to another, unless it changes from a flat third Key to a sharp third, or vice versa. For notwithstanding all the different Sounds which an imperfect Instrument will give, in different Keys, there are in Reality but two Keys, viz. a flat third Key, and a sharp third Key; and however the different Keys upon any particular Instrument may sound, we will venture to affirm, that any Piece of Music, let it be set in what Key it will, either is not true Composition, or is performed badly, if it does not sound smooth and harmonious. For though we do agree, that Variety is grateful in this Case as well as in others, yet that Variety ought to be introduced with as little Inconvenience as possible. When we shift our Scenes, we should order the Carpenters to make as little Noise in the Execution of it as they can help, and take Care that the Pullies are all well oiled. For shall any Man entertain me, by making a most hideous jarring Discord before he begins what he intends to be Harmony? It is as absurd as for a Lady to take you half a dozen Boxes on the Ear, before she permits you to salute her, and then to tell you she only did it, that you might have a more lively Apprehension of the exquisite Happiness which her unparallelled Charms should very soon make you sensible of. We may apprehend the Difference of perfect and imperfect Instruments, by listening to a Harpsichord, when any Music, where the Key changes often, is played, and to a fine Band, such as the Playhouse or the Opera. We shall find, in the latter, that the Composer has taken Care to make every Transition quite smooth and harmonious; and that tho' the Music be ever so cromatic, yet it never departs from it's melodious Effect. Whereas in an Organ or Harpsichord, even the greatest Performers cannot avoid a disagreeable Roughness in complicated Harmony. Nevertheless, as has been before observed, we must acknowledge the Organ to have Powers which other Instruments have not. * * * * * XI. _That a Piece of Music which has Flats set before it, is in a Flat Key on that Account, and vice versa with Sharps._ This is so well known to be an Error, by all those who have arrived at any Proficiency in Music, that very little need be said about it; however, it is a very common Error.