Let us look into a few of the sonatas. Most of them were written between 1760 and 1790. The few written earlier than 1760 are so obviously teaching pieces that, though they won him fame, we need not trouble to study them. Take, however, a sonata from the set published in 1774, known as opus 13, in C major (Peters No. 15). The whole first movement is built upon two rhythmical phrases which by their lilt and flow cannot fail to delight the dullest ear. There is the dotted sixteenth figure of the first theme, a theme frankly melodious for all its rhythmical vivacity; and later the same opening notes, with playful triplets added. Nothing profound or serious about it, but yet a wealth of vitality; and nearly all accomplished with but two voices. The adagio seems not at all conspicuous, yet compare it with an adagio of Clementi to see how much genuine life it has. Then the rapid little last movement, with its rocking, tilting figures, all as sparkling as sunlight. Here again, only two voices in most of the movement. Another sonata in the same set in F major (Pet. 20) is a little more developed. The quick falling arpeggio figures following the first theme are a favorite, comical device of Haydn’s. The second theme, if so it may be called, is only a series of scampering notes, with a saucy octave skip at the end; the whole full of smiles and laughter. The fine harp-like runs in the development section are reminiscent of Emanuel Bach. Haydn is noticeably fond of sudden and abrupt changes of harmony. There is one in the first section of this movement. But often he is surprisingly chromatic, more subtle in harmony than the naïve character of his music would lead one to expect him. In the opus 14, published in 1776 by Artaria, there are some joyous sonatas. The first theme of one in G major (Pet. 11) suggests Schubert by its sweetness. There is a minuet instead of a slow movement, and the final presto is a theme with lively variations. The Alberti bass on which the fourth variation floats is irresistibly naïve. Another sonata in E-flat seems richer. It is hardly less naïve and less humorous than the others in the set, but there is a warmer coloring. The overlapping imitations in the fourth, fifth, and sixth measures are strangely poignant, especially as they appear later in the restatement. There is a minuet instead of a slow movement, of which the trio is especially beautiful. The way in which the first phrase seems to be prolonged into five measures, once more suggests Schubert.