[122] This conversation, originally copied from Mr. Conduit’s handwriting, is given in the Appendix, No. iii. p. 320. [123] These were the three children of his half-brother Smith, the three children of his half-sister Pilkington, and the two daughters of his half-sister Barton, all of whom survived Sir Isaac. _New Anecdotes of Sir Isaac Newton, by J. H., a Gentleman of his Mother’s Family._ See _Annual Register_, 1776, vol. xix. p. 25 of Characters. The author of this paper was James Hutton, Esq. of Pimlico. [124] Turnor’s _Collections_, &c. p. 158. See APPENDIX, p. 316. [125] This valuable faculty characterizes all his writings, whether theological, chymical, or mathematical; but it is peculiarly displayed in his treatise on Universal Arithmetic, and in his Optical Lectures. [126] _De Magnete_, p. 42, 52, 169, and Pref. p. 30. [127] The following passages from Leonardo da Vinci are very striking: “Theory is the general, and practice the soldiers. “Experiment is the interpreter of the artifices of nature. It never deceives us; it is our judgment itself which sometimes deceives us, because we expect from it effects which are contrary to experiment. We must consult experiment by varying the circumstances till we have deduced from it general laws; for it is it which furnishes true laws. “In the study of the sciences which depend on mathematics, those who do not consult nature, but authors, are not the children of nature; they are only her grandchildren. Nature alone is the master of true genius. “In treating any particular subject, I would first of all make some experiments, because my design is first to refer to experiment, and then to demonstrate why bodies are constrained to act in such a manner. This is the method which we ought to follow in investigating the phenomena of nature. It is very true that nature begins by reasoning and ends with experiment; but it matters not, _we must take the opposite course_; _as I have said, we must begin by experiment_, and endeavour by its means to discover general principles.” Thus, says Venturi, spoke Leonard a century before Bacon, and thus, we add, did Leonard tell philosophers all that they required for the proper investigation of general laws. See _Essai sur les œuvrages physico-mathematiques de Leonard de Vinci_, par J. B. Venturi. Paris, 1799, p. 32, 33, &c. See also Carlo Amoretti’s _Memorie storiche su la vita gli studi e le Opere de Lionardo da Vinci_. Milano, 1804. [128] Mr. Hearne, in a memorandum dated April 4th, 1726, states, that a great quarrel happened between Sir Isaac Newton and Mr. Halley. If this is true, the difference is likely to have originated in Halley’s impiety. [129] Professor Rigaud of Oxford heard this anecdote from Dr. Maskelyne.