[570] Ars Memorandi, one of the oldest European block-books.
[571] Eusebius Caesariensis, De praeparatione evangelica, Venice, Jenson, 1470. The above statement holds for copies in the Astor Library and in the Harvard University Library.
[572] Francisco de Retza, Comestorium vitiorum, Nürnberg, 1470. The copy referred to is in the Astor Library.
[573] See Mauch, "Ueber den Gebrauch arabischer Ziffern und die Veränderungen derselben," Anzeiger für Kunde der deutschen Vorzeit, 1861, columns 46, 81, 116, 151, 189, 229, and 268; Calmet, Recherches sur l'origine des chiffres d'arithmétique, plate, loc. cit.
[574] Günther, Geschichte, p. 175, n.; Mauch, loc. cit.
[575] These are given by W. R. Lethaby, from drawings by J. T. Irvine, in the Proceedings of the Society of Antiquaries, 1906, p. 200.
[576] There are some ill-tabulated forms to be found in J. Bowring, The Decimal System, London, 1854, pp. 23, 25, and in L. A. Chassant, Dictionnaire des abréviations latines et françaises ... du moyen âge, Paris, MDCCCLXVI, p. 113. The best sources we have at present, aside from the Hill monograph, are P. Treutlein, Geschichte unserer Zahlzeichen, Karlsruhe, 1875; Cantor's Geschichte, Vol. I, table; M. Prou, Manuel de paléographie latine et française, 2d ed., Paris, 1892, p. 164; A. Cappelli, Dizionario di abbreviature latine ed italiane, Milan, 1899. An interesting early source is found in the rare Caxton work of 1480, The Myrrour of the World. In Chap. X is a cut with the various numerals, the chapter beginning "The fourth scyence is called arsmetrique." Two of the fifteen extant copies of this work are at present in the library of Mr. J. P. Morgan, in New York.
[577] From the twelfth-century manuscript on arithmetic, Curtze, loc. cit., Abhandlungen, and Nagl, loc. cit. The forms are copied from Plate VII in Zeitschrift für Mathematik und Physik, Vol. XXXIV.
[578] From the Regensburg chronicle. Plate containing some of these numerals in Monumenta Germaniae historica, "Scriptores" Vol. XVII, plate to p. 184; Wattenbach, Anleitung zur lateinischen Palaeographie, Leipzig, 1886, p. 102; Boehmer, Fontes rerum Germanicarum, Vol. III, Stuttgart, 1852, p. lxv.
[579] French Algorismus of 1275; from an unpublished photograph of the original, in the possession of D. E. Smith. See also p. 135.