[580] From a manuscript of Boethius c. 1294, in Mr. Plimpton's library. Smith, Rara Arithmetica, Plate I.
[581] Numerals in a 1303 manuscript in Sigmaringen, copied from Wattenbach, loc. cit., p. 102.
[582] From a manuscript, Add. Manuscript 27,589, British Museum, 1360 A.D. The work is a computus in which the date 1360 appears, assigned in the British Museum catalogue to the thirteenth century.
[583] From the copy of Sacrabosco's Algorismus in Mr. Plimpton's library. Date c. 1442. See Smith, Rara Arithmetica, p. 450.
[584] See Rara Arithmetica, pp. 446-447.
[585] Ibid., pp. 469-470.
[586] Ibid., pp. 477-478.
[587] The i is used for "one" in the Treviso arithmetic (1478), Clichtoveus (c. 1507 ed., where both i and j are so used), Chiarini (1481), Sacrobosco (1488 ed.), and Tzwivel (1507 ed., where jj and jz are used for 11 and 12). This was not universal, however, for the Algorithmus linealis of c. 1488 has a special type for 1. In a student's notebook of lectures taken at the University of Würzburg in 1660, in Mr. Plimpton's library, the ones are all in the form of i.
[588] Thus the date
