330 System of Logic, bk. iii. chap. viii. § 4, 5th ed. vol. i. p. 433.

331 Essayes of Natural Experiments made in the Accademia del Cimento. Englished by Richard Waller, 1684, p. 40, &c.

332 Plateau, Taylor’s Scientific Memoirs, vol. iv. pp. 16–43.

333 Philosophical Transactions [1826], vol. cxvi. pp. 388, 389. Works of Sir Humphry Davy, vol. v. pp. 1–12.

334 National Review, July, 1861, p. 13.

335 His published works are contained in The Edinburgh Physical and Literary Essays, vol. ii. p. 34; Philosophical Transactions [1753], vol. xlviii. p. 261; see also Morgan’s Papers in Philosophical Transactions [1785], vol. lxxv. p. 190.

336 Edinburgh Journal of Science, vol. v. p. 79.

337 Encyclopædia Metropolitana, art. Light, § 524; Herschel’s Familiar Lectures, p. 266.

338 Talbot, Philosophical Magazine, 3rd Series, vol. ix. p. 1 (1836); Brewster, Transactions of the Royal Society of Edinburgh [1823], vol. ix. pp. 433, 455; Swan, ibid. [1856] vol. xxi. p. 411; Philosophical Magazine, 4th Series, vol. xx. p. 173 [Sept. 1860]; Roscoe, Spectrum Analysis, Lecture III.

339 Balfour Stewart, Elementary Treatise on Heat, p. 192.

340 British Association, Liverpool, 1870. Report on Rainfall, p. 176.

341 Philosophical Magazine., Dec. 1861. 4th Series, vol. xxii. p. 421.

342 Experimental Researches in Electricity, vol. iii. p. 84, &c.

343 Lectures on Heat, p. 21.

344 Baily, Memoirs of the Royal Astronomical Society, vol. xiv. pp. 29, 30.

345 Grant, History of Physical Astronomy, p. 531.

346 Philosophical Transactions, abridged by Lowthorp, 4th edition, vol. i. p. 202.

347 Jevons in Watts’ Dictionary of Chemistry, vol. ii. pp. 936, 937.

348 Discovery of Subterraneal Treasure. London, 1639, p. 48.

349 Laplace, System of the World, translated by Harte, vol. ii. p. 322.

350 Principia, bk. ii. sect. 6, Prop. xxxi. Motte’s translation, vol. ii. p. 108.

351 Essayes of Natural Experiments, &c. p. 117.

352 Hooke’s Posthumous Works, p. 182.

353 Principia, bk. iii. Prop. vii. Corollary 1.

354 Keill’s Introduction to Natural Philosophy, 3rd ed., London, 1733, pp. 48–54.

355 Discovery of Subterraneal Treasure, 1639, p. 52.

356 Elements of Inductive Logic, 1st edit. p. 175.

357 Philosophical Transactions, vol. li. p. 138; abridgment, vol. xi. p. 355.

358 See Bunsen and Roscoe’s researches, in Philosophical Transactions (1859), vol. cxlix. p. 880, &c., where they describe a constant flame of carbon monoxide gas.

359 Humboldt’s Cosmos (Bohn), vol. i. p. 7.

360 Gilbert, De Magnete, p. 109.

361 Principia, bk. iii. Prop. vi.

362 Philosophical Magazine, 3rd Series, vol. xxvi. p. 375.

363 Opticks, 3rd edit. p. 159.

364 Watts, Dictionary of Chemistry, vol. iii. p. 637.

365 Faraday’s Life, by Bence Jones, vol. ii. p. 5.

366 Preliminary Discourse, &c., p. 185.

367 Philosophical Magazine, July, 1857, 4th Series, vol. xiv. p. 24.

368 First Principles, 3rd edit. chap. x. p. 253.

369 Laplace, System of the World, vol. i. pp. 50, 54, &c.

370 Herschel’s Outlines of Astronomy, 4th edit. pp. 555–557.

371 Humboldt’s Cosmos (Bohn), vol. iii. p. 229.

372 Encyclopædia Metropolitana, art. Sound, § 323; Outlines of Astronomy, 4th edit., § 650. pp. 410, 487–88; Meteorology, Encyclopædia Britannica, Reprint, p. 197.

373 Philosophical Transactions, (1739), vol. xli. p. 126.

374 Principia, bk. iii. Prop. 15.

375 Lockyer’s Lessons in Elementary Astronomy, p. 301.

376 Treatise on Natural Philosophy, vol. i. pp. 337, &c.

377 An Introduction to Natural Philosophy, 3rd edit. 1733, p. 5.

378 Watts, Dictionary of Chemistry, vol. i. p. 455.

379 Philosophical Transactions, (1866) vol. clvi. p. 809.

380 Experimental Researches in Electricity, vol. i. p. 246.

381 Hutton’s Mathematical Dictionary, vol. ii. pp. 287–292.

382 Principia, bk. iii. Prop. 13.

383 Jamin, Cours de Physique, vol. i. pp. 282, 283.

384 Lloyd’s Lectures on the Wave Theory, pp. 22, 23.

385 Tait’s Thermodynamics, p. 10.

386 Lloyd’s Lectures on the Wave Theory, pp. 82, 83.

387 Jamin, Cours de Physique, vol. i. pp. 283–288.

388 Joule and Thomson, Philosophical Transactions, 1854, vol. cxliv. p. 337.

389 The properties of a perfect gas have been described by Rankine, Transactions of the Royal Society of Edinburgh, vol. xxv. p. 561.

390 Thomson and Tait’s Natural Philosophy, vol. i. p. 60.

391 Challis, Notes on the Principles of Pure and Applied Calculation, 1869, p. 83.

392 An Introduction to Physical Measurements, translated by Waller and Procter, 1873, p. 10.

393 Cambridge Philosophical Transactions (1865), vol. xi. Part I.

394 Sandeman, Pelicotetics, p. 214.

395 The Science and Art of Arithmetic for the Use of Schools. (Whitaker and Co.)

396 Principles of Approximate Calculations, by J. J. Skinner, C.E. (New York, Henry Holt), 1876.

397 Leslie, Inquiry into the Nature of Heat, p. 505.

398 System of Logic, bk. iii. chap. viii § 6.

399 Laplace, System of the World, translated by Harte, vol. ii. p. 366.

400 Chemical Reports and Memoirs, Cavendish Society, p. 294.

401 Jamin, Cours de Physique, vol. ii. p. 38.

402 On Tides and Waves, Encyclopædia Metropolitana, p. 366*.

403 Encyclopædia Britannica, art. Meteorology. Reprint, §§ 152–156.

404 Lagrange, Leçons sur le Calcul des Fonctions, 1806, p. 4.

405 Haughton, Principles of Animal Mechanics, 1873, pp. 444–450. Jevons, Nature, 30th of June, 1870, vol. ii. p. 158. See also the experiments of Professor Nipher, of Washington University, St. Louis, in American Journal of Science, vol. ix. p. 130, vol. x. p. 1; Nature, vol. xi. pp. 256, 276.

406 Jamin, Cours de Physique, vol. ii. p. 50.

407 Philosophical Transactions, 1826, p. 544.

408 Jamin, Cours de Physique, vol. ii. p. 24, &c.

409 J. W. Strutt, On a correction sometimes required in curves professing to represent the connexion between two physical magnitudes. Philosophical Magazine, 4th Series, vol. xlii. p. 441.

410 Herschel: Lacroix’ Differential Calculus, p. 551.

411 Cours complet de Météorologie, Note A, p. 449.

412 On the Calculation of Empirical Formulæ. The Messenger of Mathematics, New Series, No. 17, 1872.

413 Watts’ Dictionary of Chemistry, vol. ii. p. 790.

414 Quarterly Journal of the Chemical Society, vol. viii. p. 15.

415 Results of Observations at the Cape of Good Hope, p. 293.

416 Jamin, Cours de Physique, vol. ii. p. 138.

417 Preliminary Discourse, &c., p. 152.

418 Tyndall, On Cometary Theory, Philosophical Magazine, April 1869. 4th Series, vol. xxxvii. p. 243.

419 See Philosophical Transactions, abridged by Lowthorp. 4th edit. vol. i. p. 130. I find that opinions similar to those in the text have been briefly expressed by De Morgan in his remarkable preface to From Matter to Spirit, by C.D., pp. xxi. xxii.

420 Horrocks, Opera Posthuma (1673), p. 276.

421 Young’s Works, vol. i. p. 593.

422 Boyle’s Physical Examen, p. 84.

423 Young’s Works, vol. i. p. 415.

424 Familiar Lectures on Scientific Subjects, p. 282.

425 Young’s Works, vol. i. p. 417.

426 Principia, bk. iii. Prop. 43. General Scholium.

427 Ibid. bk. ii. Sect. ix. Prop. 53.

428 Brewster’s Life of Newton, 1st edit. chap. vii.

429 Discourse on the Study of Natural Philosophy, p. 151.

430 Ibid. p. 229.

431 Novum Organum, bk. ii. Aphorism 36.

432 Principia, bk. i. Sect. xiv. Prop. 96. Scholium. Opticks, Prop. vi. 3rd edit. p. 70.

433 Airy’s Mathematical Tracts, 3rd edit. pp. 286–288.

434 Jamin, Cours de Physique, vol. iii. p. 372.

435 Young’s Lectures on Natural Philosophy (1845), vol. i. p. 361.

436 Paris, Life of Davy, p. 274.

437 Opus Majus. Edit. 1733. Cap. x. p. 460.

438 Newton’s Opticks. Third edit. p. 249.

439 Brewster. Treatise on New Philosophical Instruments, p. 266, &c.

440 Roscoe, Bakerian Lecture, Philosophical Transactions (1868), vol. clviii. p. 6.

441 Life of Faraday, vol. ii. p. 104.

442 Watts, Dictionary of Chemistry, vol. ii, p. 39, &c.

443 De Morgan’s Budget of Paradoxes, p. 291.

444 Life of Faraday, vol. ii p. 396.

445 Experimental Researches in Electricity, 1st Series, pp. 24–44.

446 Airy, On Tides and Waves, Encyclopædia Metropolitana, p. 348*

447 Lib. i. cap. 74.

448 Taylor’s Scientific Memoirs, vol. v. p. 241.

449 Airy’s Mathematical Tracts, 3rd edit. p. 312.

450 Young’s Works, vol. i. p. 412.

451 Lloyd’s Wave Theory, Part ii. pp. 52–58. Babbage, Ninth Bridgewater Treatise, p. 104, quoting Lloyd, Transactions of the Royal Irish Academy, vol. xvii. Clifton, Quarterly Journal of Pure and Applied Mathematics, January 1860.

452 Encyclopædia Metropolitana, art. Sound, p. 753.

453 Tyndall’s Sound, pp. 261, 273.

454 Whewell’s History of the Inductive Sciences, vol. ii. p. 471. Herschel’s Physical Geography, § 77.

455 Maxwell’s Theory of Heat, p. 174. Philosophical Magazine, August 1850. Third Series, vol. xxxvii. p. 123.

456 Philosophical Transactions, 1858, vol. cxlviii. p. 127.

457 Tyndall’s Faraday, pp. 73, 74; Life of Faraday, vol. ii. pp. 82, 83.

458 Tait’s Thermodynamics, p. 77.

459 On the Analytical Forms called Trees, with Application to the Theory of Chemical Combinations. Report of the British Association, 1875, p. 257.

460 Hofmann’s Introduction to Chemistry, pp. 224, 225.

461 Philosophical Transactions (1855), vol. cxlv. pp. 100, &c.

462 Proceedings of the Manchester Philosophical Society, Feb. 1870.

463 Balfour Stewart, Elementary Treatise on Heat, 1st edit. p. 198.

464 Jevons, Proceedings of the Manchester Literary and Philosophical Society, 25th January, 1870, vol. ix. p. 78.

465 Philosophical Transactions, vol. cxlvi. p. 249.

466 Grant’s History of Physical Astronomy, p. 162.

467 Philosophical Transactions (1854), vol. cxliv. p. 364.

468 Monthly Notices of the Royal Astronomical Society, vol. xxviii. p. 264.

469 It would seem to be absurd to repeat the profuse expenditure of 1874 at the approaching transit in 1882. The aggregate sum spent in 1874 by various governments and individuals can hardly be less than £200,000, a sum which, wisely expended on scientific investigations, would give a hundred important results.

470 Philosophical Transactions (1856), vol. cxlvi. p. 342.

471 Monthly Notices of the Royal Astronomical Society, for 8th Nov. 1844, No. X. vol. vi. p. 89.

472 Philosophical Magazine, 2nd Series, vol. xxvi. p. 61.

473 Clausius in Philosophical Magazine, 4th Series, vol. ii. p. 119.

474 Watts’ Dictionary of Chemistry, vol. iii. p. 129.

475 Preliminary Discourse, §§ 158, 174. Outlines of Astronomy, 4th edit. § 856.

476 Proceedings of the Manchester Literary and Philosophical Society, 28th November, 1871, vol. xi. p. 33. Since the above remarks were written, Professor Balfour Stewart has pointed out to me his paper in the Proceedings of the Manchester Literary and Philosophical Society for 15th November, 1870 (vol. x. p. 32), in which he shows that a body moving in an enclosure of uniform temperature would probably experience resistance independently of the presence of a ponderable medium, such as gas, between the moving body and the enclosure. The proof is founded on the theory of the dissipation of energy, and this view is said to be accepted by Professors Thomson and Tait. The enclosure is used in this case by Professor Stewart simply as a means of obtaining a proof, just as it was used by him on a previous occasion to obtain a proof of certain consequences of the Theory of Exchanges. He is of opinion that in both of these cases when once the proof has been obtained, the enclosure may be dispensed with. We know, for instance, that the relation between the inductive and absorptive powers of bodies—although this relation may have been proved by means of an enclosure, does not depend upon its presence, and Professor Stewart thinks that in like manner two bodies, or at least two bodies possessing heat such as the sun and the earth in motion relative to each other, will have the differential motion retarded until perhaps it is ultimately destroyed.

477 British Association Catalogue of Stars, p. 49.

478 Experimental Researches in Chemistry and Physics, p. 372. Philosophical Magazine, 3rd Series, May 1846, vol. xxviii. p. 350.

479 See also Nature, September 18, 1873; vol. viii. p. 398.

480 Theory of Political Economy, pp. 3–14.

481 Principia, bk. i. Prop. iv.

482 Opticks, bk. i. part ii. Prop. 3. 3rd ed. p. 115.

483 Experimental Inquiry into the Nature of Heat. Preface, p. xv.

484 Bence Jones, Life of Faraday, vol. i. p. 362.

485 Ibid. vol. ii. p. 199.

486 See also his more formal statement in the Experimental Researches in Electricity, 24th Series, § 2702, vol. iii. p. 161.

487 Printed in Modern Culture, edited by Youmans, p. 219.

488 Life of Faraday, vol. i. p. 225.

489 Aristotle’s Rhetoric, Liber I. 2. 11.

490 Essai Philosophique sur les Probabilités, p. 86.

491 Kant’s Logik, § 84, Königsberg, 1800, p. 207.

492 Syllabus of a Proposed System of Logic, p. 34.

493 Principia, bk. iii. Prop. VI. Motte’s translation, vol. ii. p. 220.

494 Professor Lovering has pointed out how obscure and uncertain the ideas of scientific men about this ether are, in his interesting Presidential Address before the American Association at Hartford, 1874. Silliman’s Journal, October 1874, p. 297. Philosophical Magazine, vol. xlviii. p. 493.

495 Novum Organum, bk. ii. Aphorisms, 24, 25.

496 Ibid. Aph. 28.

497 Philosophical Transactions (1856) vol. cxlvi. p. 246.