[66] _Quest. nat._, cap. 21. [67] _De architectura_, V, iii, 6 (Morgan’s translation). “Voice is a flowing breath of air, perceptible to the hearing by contact. It moves in an endless number of circular rounds, like the innumerably increasing circular waves which appear when a stone is thrown into smooth water, and which keep on spreading indefinitely from the center unless interrupted by narrow limits, or by some obstruction which prevents such waves from reaching their end in due formation. When they are interrupted by obstructions, the first waves, flowing back, break up the formation of those which follow.” [68] _Quest. nat._, cap. 22. [69] See above, chapter 5, vol. I, page 191. [70] _Quest. nat._, cap. 23. [71] See above, chapter 28, I, 659. [72] See above, chapter 28, I, 657. [73] See above, chapter 3, page 107. [74] _De Genesi ad litteram_, IV, 34; Migne, PL 34, 319-20. [75] _Quest. nat._, caps. 8-9. [76] _Ibid._, cap. 17. [77] _Ibid._, cap. 32. On “weeping as a salutation,” see J. G. Frazer (1918) II, 82-93. [78] _Quest. nat._, cap. 2. [79] _Ibid._, caps. 13-14. [80] _Ibid._, cap. 48. [81] Chapter 6, I, 219. [82] London Weekly Times, Literary Supplement, Nov. 15, 1918, p. 549. [83] _Quest. nat._, cap. 4, “Et meo certo iudicio in hoc sensibili mundo nihil omnino moritur nec minor est hodie quam cum creatus est. Si qua pars ab una coniunctione solvitur, non perit sed ad aliam societatem transit.” [84] _Didascalicon_ I, 7 (Migne, PL 176). [85] Plotinus had said, “Nothing that really is can ever perish” (οὐδὲν ἀπολεῖται τῶν ὄντων), as Dean Inge notes, _The Philosophy of Plotinus_, 1918, I, 189. There is also resemblance between the _Didascalicon_ (II, 13) and _De eodem et diverso_ (p. 27, line 7) in their division of music into mundane, human, and instrumental. For this Boethius is very likely the common source. [86] In _Roger Bacon Commemoration Essays_, ed. by A. G. Little, Oxford, 1914, pp. 241-84. [87] _Roger Bacon Essays_, p. 266. [88] _Quest. nat._, cap. 16. For a somewhat similar passage in Augustine see _De Genesi ad litteram_, VII, 18 (Migne, PL 34, 364). [89] _Ibid._, cap. 18. [90] See above, chapter 5, I, 191. [91] That is, 78 and 77. [92] _De eodem et diverso_, p. 32. [93] _Ibid._, p. 10. [94] _Ibid._, p. 13. [95] _Quest. nat._, caps. 74-77. [96] Cotton Titus D, iv, fols. 75-138v, opening “fiat ordinata parato quo facile amplectamur ...”, and closing “pars tercia tocius orbis terreni, unde reliqua duo spacia reliqua.” [97] Cotton Titus D, iv, fol. 77r. [98] _Ibid._, fol. 78r. [99] _Ibid._, fol. 126v. [100] _Ibid._, fols. 127-32. [101] _Ibid._, fols. 113-4. [102] _Ibid._ fol. 113v, “Et antiqui scripture arguunt et hodierni temporis experimentum probat”.... [103] _Ibid._, fols. 120v-124v. APPENDIX I THE PROBLEM OF DATING THE DE EODEM ET DIVERSO AND QUESTIONES NATURALES AND OF THEIR RELATIONS TO EACH OTHER [Sidenote: Difficulty of the problem.]