Published online by Cambridge University Press: 04 April 2011
[…] point of time over the keyed instruments used for similar purposes; and its qualities and requirements so reacted upon the character of the music as to make it appear almost a distinct species from the Clavier Sonata. But in fact the two kinds represent no more than divergence from a similar source, owing to the dissimilar natures of the instruments. Thus the introductory slow movement was most appropriate to the broad and noble character of the violin, and would appeal at once by its means to an audience of any susceptibility; whereas to the weak character of the early keyed instruments, so deficient in sustaining power, it was in general inappropriate, and hence was dropped very early. For the same reason in a considerable proportion of the early clavier sonatas, the third or principal slow movement was also dropped, so that the average type of sonatas for clavier was for a time a group of two movements, both generally in a more or less quick time. In these the canzona movement was early supplanted by one more in accordance with the modern idea, such as is typified in the clavier sonata of Galuppi in four movements [see p. 563], and by occasional allemandes in the earlier sonatas. As keyed instruments improved in volume and sustaining power the central slow movement was resumed; but it was necessary for some time to make up for deficiencies in the latter respect by filling in the slow beats with elaborate graces and trills, and such ornaments as the example of opera-singers made rather too inviting.