1. J. Stirling, Methodus Differentiate, London, 1730, p. 58
2. English transl, by F. Holliday, London, 1749, p. 51.
3. K. F. Gauss, Werke, v. 3, Göttingen, 1866, p. 413.
4. John Chapman, the publisher, at whose home George Eliot resided Jan. 8 to March 24, 1851.
5. Adriaan van Roomen (or Adrianus Romanus), Ideae mathematicae pars prima, sive methodus polygonorum. Louvain and Antwerp, 1593. In preliminary material Roomen has (i) “lectori philomathi” in which he has words of praise for 15 of the principal mathematicians of his time (including Rheticus and Valentin Otho), and (ii) a letter written by Rheticus in 1568 to Petrus Ramus (1515-1572), telling not only of his great tabular calculations but also of such works as the following which he planned to publish: (a) Observation of Phenomena; (b) German astronomy; (c) Natural Philosophy; (d) Foundations of Chemistry. See H. Bosmans, “Romain (Adrien),” Biogr. Nationale . . . de Belgique. Brussels, v. 19, 1907, col. 855; also A. Müller,²³ p. 40.