255 Bach’s Clavier school consisted of eighteen Preludes for beginners (all in B.G. XXXVI.); the two-part and three-part Inventions; and the _Well-tempered Clavier._ The six Preludes mentioned by Forkel, and which alone he knew, were published by him for the first time. Seven more are found in Wilhelm Friedemann’s _Clavierbüchlein_ (B.G. XLV. (1)), and the remaining five have survived in texts handed down by others of Bach’s pupils. The eighteen are in P. bk. 200. 256 The Autograph was written at Cöthen and is dated 1723. It also contains the fifteen Symphonies, or three-part Inventions mentioned in paragraph 3. Both Inventions and Symphonies are in F. bk. 201. According to Spitta (ii. 57 n.) the Inventions were published at Leipzig in 1763. See also Schweitzer, i. 328 ff. 257 See the previous note. 258 The second Part was compiled in 1744 and Bach’s Autograph of it, though not the earliest Autograph, is in the British Museum. See Schweitzer, i. 331 ff. and Spitta, ii. 161 ff. The whole work is in P. bks. 1, 2; or 1a, 1b; or 2790a, 2790b. 259 No. 20. Spitta (ii. 164) attributes it to the years 1707 or 1708. Schweitzer (i. 332) also regards it as a youthful piece written, moreover, for the pedal Clavicembalo. 260 Nos. 15 and 16. Spitta, admitting that the two do not rank with the most interesting in the collection, finds no indication of their being of different date from the best movements. 261 No. 1. Here Spitta (ii. 165 n.) challenges Forkel. 262 Nos. 11 and 12. In regard to No. 12 (F minor) Spitta holds Forkel to be in error. As to No. 11, he expresses the same opinion as in note 3, supra. 263 The date 1744 places the second Part among Bach’s latest compositions. On the other hand, like the first Part, it contained work of earlier date. 264 Chromatic Fantasia and Fugue in D minor (P. bk. 207 p. 4). It probably dates from circ. 1720-23. 265 The MS. was discovered in 1876 and is now at Dresden. It was written circ. 1738 and disproves Forkel’s conjecture that the fugue did not belong to the Fantasia and is only partially by Bach. The Fugue contains forty-seven bars. As the Autograph is a fair copy the Fugue cannot be called unfinished. See Spitta, iii. 182. The Fantasia is in P. bk. 207 p. 50; the Fugue in P. bk. 212 p. 88. See B.C. xxxvi., xxxviii., and xlii. for other Clavier Fantasias.