Discoveries and Inventions of the Nineteenth Century

were in their grave, The Moon, their mistress, had expired before; The winds were withered in the stagnant air, And the clouds perished; Darkness had no need Of aid from them—She was the Universe.” The doctrine of this persistence and dissipation of energy completely harmonizes with the grand speculation termed the “nebular hypothesis,” which regards the universe as having originally consisted of uniformly diffused matter, which, being endowed with the power of gravitation, aggregated round certain centres. This process is still going on; and, according to modern speculations, light and life and motion are but manifestations of this primæval potential energy being converted into actual energy, and degrading ultimately into the form of universally-diffused heat. To quote the closing sentences of the eloquent passage in which Professor Tyndall concludes the work mentioned above, “To nature nothing can be added, from nature nothing can be taken away; the sum of her energies is constant, and the utmost man can do in the pursuit of physical truth, or in the 810applications of physical knowledge, is to shift the constituents of the never-varying total. The law of conservation rigidly excludes both creation and annihilation. Waves may change to ripples, and ripples to waves; magnitude may be substituted for number, and number for magnitude; asteroids may aggregate to suns, suns may resolve themselves into floræ and faunæ, and floræ and faunæ melt in air: the flux of power is eternally the same. It rolls in music through the ages, and all terrestrial energy—the manifestations of life as well as the display of phenomena—are but the modulations of its rhythm.” The discoveries to which we have here endeavoured to attract the reader’s attention thus give rise to conceptions of the utmost grandeur and interest. We see that the sum of Nature’s energies is constant; that all the manifestations of force are but the transference of power from one position to another. And we have recognized the material source of all our terrestrial energies in the sun. Two theories have already been mentioned by which it is sought to account for the sun’s heat—the meteoric theory of Meyer and Thomson, and the shrinkage theory of Helmholtz. These both assume gravitation as the primal force from which the supply of heat and other energies must be drawn, and they assume also that the laws of radiation and of the degradation of temperature in the transformation of heat into other forces, as we find them operating at the earth’s surface, are equally in action in every region of space. Hence is deduced that conception of the final state of the universe as one of merely equally diffused temperature admitting of no further transformation. This speculation presents the universe in the aspect of a clock, now indeed going, but when once run down, incapable of ever being again wound up. There seems in this view a want of symmetry, so to speak; we miss the feeling of harmonious rhythm to which Tyndall refers. There is, however, another cosmic theory, well supported by accumulating facts, which assigns to gravitation a less important part in the production of solar heat and in the evolution of worlds, and it is one which supplies also a basis for the explanation of such phenomena as aerolites, comets, variable stars, the inclination of planets’ axes to their orbits, the proper motion of our sun, and that of the so called fixed stars, of all of which the nebular hypothesis fails to give any account; while, on the other hand, the impact theory, as it has been named, includes the other, and goes beyond it. The reader who desires to pursue this subject may be referred to Croll’s book on Stellar Evolution. In the last few paragraphs we have been dealing with speculations as much as with discoveries. But indeed the former are the offspring of the latter, as certainly as one invention becomes the parent of others. The human mind never rests contented with the knowledge and mastery of nature actually gained, but ever seeks to pass beyond and attain still greater power. The volume we are now bringing to a close has given but brief and imperfect indications of specimens, taken here and there, of what has been done during the short period of one century. We may draw an augury for the future of man’s dominion from the powers his Promethean spirit has already grasped: “The lightning is his slave; heaven’s utmost deep Gives up her stars, and like a flock of sheep They pass before his eye, are numbered, and roll on! The tempest is his steed, he strides the air; And the abyss shouts from her depth laid bare, “Heaven, hast thou secrets? Man unveils me; I have none.” 811 NOTES A and B. 812 Note A—Continuation of Table on page 755, showing the quantity of Coals raised annually in Great Britain. Year. Coal raised in Tons. 1874 126,590,108 1875 133,306,458 1876 134,125,166 1877 134,179,968 1878 132,612,063 1879 133,720,393 1880 146,969,409 1881 154,184,300 1882 156,499,977 1883 163,737,327 1884 160,757,779 1885 159,351,418 1886 157,518,482 1887 162,121,576 1888 169,935,219 1889 176,916,724 1890 181,614,280 1891 185,479,126 1892 181,786,871 1893 164,325,795 1894 188,277,525 Note B—CONSERVATION OF ENERGY.—Page 804. The statement here should have been more explicit, as it has reference to a state of things not to be realised in practice. Like the well-known “first law of motion,” it can neither be demonstrated à priori, nor proved by any direct and simple experiment. The first law of motion asserts that a body in motion, not acted on by any external force, will continue to move in a straight line, and with a uniform velocity. Now we cannot place a body in such a position that it will not be acted upon by some external forces; but the more we lessen the effect of external forces, the more nearly is the motion straight and uniform. Similarly in the case supposed, the intention is to show that the weight carried up is in a position to do just as much work as was done upon it. We must suppose several impracticable but conceivable conditions in order to eliminate considerations which do not concern the theoretical question; we must suppose the cord to be weightless and absolutely devoid of rigidity; the pulley to have no mass or inertia, that is to require no force to set it in motion, and to move without any friction; the air to offer no resistance; and the force of gravity to be uniform throughout the space. Some approximation to these conditions is practicable, as, for example, the pulley might be the lightest possible, and turn on friction wheels, the cord might be the finest silk thread, and so on. But it is not the influence of these external forces we are considering, but only the energy due to the position of the raised weight. Assuming, therefore, the disturbing conditions absolutely eliminated, it is not difficult to see that no downward force or pressure, however small, could be applied for ever so short a time, to the upper weight without setting the system in motion. The motion would be an accelerated one so long as the force was applied, it would become uniform when the force ceased to act; it would have a velocity proportionate to the force. In any case, after a time the descending weight would reach the ground, and for our point of view it is quite immaterial whether the time occupied by the movement were 5 minutes or 5,000 years, for be it observed, time does not enter into the definition of work as it does into that of “horse-power.” Then by pushing the conceived conditions to their limits, we may see that without considering any question of conversion of motion into heat, the raised weight can, in theory at least, give back again the energy spent upon it. 813 INDEX A. Abel, Professor, 746. Accumulators, 530. Adhesion of locomotive, 21. Advantages of present age, 2. Aerolites, 30. Air, 734. Albert Bridge, Saltash, 283. Alizarine, 797. “Alliance” magneto-electric machine, 520. Aluminium, 717. bronze, 719. reduced cost of, 723. American Tract Society building, 78. Ampère’s hypothesis, 750. rule, 492, 549. Amphioxus, 679. Anæsthetics, 731. Anemometer, 656. Angle, limiting, or critical, 399. Aniline, 787. black, 793. blue, 790. green, 791. purple, 788. Anomalous magnetisation, 538. Anthea Cereus, 678. Anthracene, 796, 797. Applegath printing machine, 312. and Cowper, ditto, 308. Apps’s anemometer, 656. induction coil, 506. Aquaria, 675. Arago, 599. Architecture, use of iron in, 72. Argand gas burners, 773. lamps, 595. Armours, ships’, strengths of, 166. Armstrong 110–ton gun, 202. Armstrong’s guns, 192. hydraulic crane, 333. Atoms, 733, 743. Aurora, 504. Australian gold, 688. Austrian torpedoes, 229. “Automobile” competition, 23. Axolotl, 686. B. Bacon, Francis, 799. Balloon, photographic, 628. Basic process (Gilchrist’s), 66. Battery, galvanic, 493. 814Battery, secondary, 530. Baxter House experiments, 58. Bell Rock Lighthouse, 593. Bells, electro-magnetic, 554. Benzol, 783. Bessemer, 26, 56. Channel steamer, 142. converter, 63. iron, 62. process, 64. steel, 56–67. Big Wheels, 81. Bitter Lakes, 261. Blanchard lathe, the, 86. Blast furnace, 40. Blind spot in eye, 460. Blister steel, 54. Blood spectra, 431. Boilers of steam engines, 13. Boring for coals, 361. Bourdon’s pressure gauge, 12. Bourseul, M., 582. Box girders, 280. Breakwater, 258. Breakwaters for Suez Canal, 258. Breech-loading rifles, 182. Brewster, Sir D., 405, 420, 470, 474. Bridge, projected Channel, 296. Bridgewater Canal, 250, 266. Brighton Aquarium, 682. Britannia Bridge, 280. raising tubes, 336. British Aluminium Co., 723. British navy in 1894, 167. Brooklyn Bridge, 303. “Brown Bess,” 178. Browning’s micro-spectroscopes, 434. spectroscope, 422, 432. Brunel, 283. Brunswick rifle, 180. Brush dynamo, 522. Bullet, Greener’s expanding, 182. Lebel, 188. Minié, 180. Bullets, machinery for making, 330. Bunsen and Kirchhoff, 422. and Roscoe, 720. Bunsen’s battery, 496. burner, 421. Bye-products in gas making, 772. C. Cable railways, 126. Cæsium, 426. 815Caissons for Forth Bridge, 293. Calais-Douvres, steamship, 141. Caledonian Canal, 250. Calico printing machines, 321. California, discovery of gold in, 688. Camera, 613. Canal, Caledonian, 250. Manchester Ship, 262. Nicaragua, 274. North Sea, 271. Panama, 272. Suez, 251. Cantilever Bridges, 291. “Cape Horn,” 120. Captain, H.M.S., 141. Carbon transmitter, 590. Carbonic oxide, 44, 48. Carbons for arc lights, 527. Carcel lamp, 597. Carpenter, Dr. W. B., 462. Carriages, railway, 111. for rock drills, 358. Carriers in pneumatic tubes, 344. Cars, Pullman, 112. Castalia, steamship, 139. Cast-iron, composition of, 43. Cast steel, 54. Catoptric lighthouse apparatus, 599. Cause of light and colour, 408. Celestial chemistry and physics, 436. Celluloid, 622. Central Telegraph Office, London, 574. Centres of gravity and buoyancy, 149. Centrifugal force, 107. Chains, 330. Chain-testing machine, 329. Channel Bridge (projected), 296. steamers, 142. Channel Tunnel, 364. Chassepot rifle, 182. Chemical action of light, 608. equations, 734. nomenclature, 782. symbols, 733. work of electricity, 497. Chloroform, 608. Chromatic aberration of eye, 462. Chromo-lithography, 638. Chronograph} Chronoscope} electric, 656. Cincinnati Suspension Bridge, 287. City of Rome, steamship, 139. Clark’s hydraulic lift graving dock, 331. Clarke’s magneto-electric machine, 509. Clay process, stereotyping by, 633. Clerk Maxwell’s theory of light, 541. “Clermont,” the, 147. Clifton Suspension Bridge, near Bristol, 285. Niagara, 287. Coal, 751. Coal in Kent, 371. Coal-gas, 764. Coal-tar colours, 781. Code, telegraphic, of American War Department, 528. Morse’s, 560. Wheatstone’s dot, 565. Cold-short iron, 62. Colesberg, 703. Collodion process, 618. Colour printing, 639. Colours not in the objects, 413. photography of, 628. Comets, spectra of, 444. 816Composition rollers, 406. Condie’s steam-hammer, 28. Copying principle, 86. Cordite, 748. Corona, 438. Cort’s puddling furnace, 45. Couple, mechanical, 149. Cramp gauge, 129. Croll, on Stellar Evolution, 810. Crookes, 507. Crystal Palace, an example of use of iron in architecture, 72. Crystal Palace, 72. Aquarium, 677. Crystalline lens, 455. Cup and cone, 49. Current, electric, 492. induced, 502. measurement of, 536. Currents in submarine cables, 579. D. Daguerre, 609. Daguerreotype, 610. Daimler motor, 24. Dallmeyer, 617. Daniell’s battery, 495. De Beers Mines, 707. Delphi, oracle at, 739. Dial telegraphs, 566. Diamond cutting, 700. Diamond, qualities of the, 698. rock drill, 359. Diamondiferous, 703. Diamonds, 696. use of, 701. Dioptric lighthouse apparatus, 600. Discoveries, progressive, 802. Dissipation of energy, 808. Distinct vision, 458. D lines of sodium spectrum, 425, 441. Dolls, talking, 674. Domestic consumption of coal, 755, 756. Double refraction and polarization, 399. Dredges, Suez Canal, 255. Drilling machine, 90. Dry digging, 702. Duboscq’s electric lamp, 497. Du Moncel, 590. Dynamical electricity, 490. Dynamo, Siemens’, 522. Brush, 522. E. Earl’s Court, Great Wheel at, 83. Earth’s circuit, 574. Ebonite, 728. Eccentric, 9. Eclipse of sun, 438. Eddystone lighthouse, 594. Edison, 669, 670, 674. Edison’s kinetoscope, 478. Eiffel Tower, the, 72. Electric lighting and electric power, 519. Electric current, 790. furnace, 722. Electric induction, 488. launch, 534. light, cost of, 43. 817Electric light in lighthouses, 515. telegraph, 598. torpedo, 547. tramway, 532. welding, 537. Electricity, 481. Electricity, the new, 538. Electrode, 497. Electro-magnet, 500. Electromotive force, 494. Electro-plating, 499, 518. Electrotyping, 634. Elementary bodies, 716. Elementary phenomena of magnetism and electricity, 483. Elswick 4·7–in. gun, 206. guns, 194. Energy, 806. Ether, 735. the luminiferous, 408. Exhaustion of coal, 755, 756, 757. Expansive working of steam, 8, 17. Explosion by concussion, 745. of locomotive, 21. of torpedoes, 229. Explosives, 225, 740. different effects of, 748. names and classes of, 750. Eye, the, 451. dimensions of some parts of, 462. Eye not optically perfect, 462. Eyeballs, muscles of, 461. F. Fairbairn, Sir W., 280. Faraday, 506, 508, 735. ventilating gas-burner, 773. Faure’s accumulator, 530. Fellahs, 255. Ferris wheel, Chicago, 81. Field telegraphs, 555. Fire-arms, 169. Fish-plates, 105. Fizeau, 386. Floating matter in air, 383. Fluids, electric, 487. Fly-wheels, 7. Force, conservation of, 804. electromotive, 494. Forth Bridge, the, 311. Foucault, 387. Fovea centralis, 456, 457. Fraser-Woolwich guns, 195. Fraunhofer’s lines, 420, 436. Fresnel’s mirrors, 409. measurement of velocity of light, 600. Fribourg Suspension Bridge, 286. Froment’s dial telegraph, 567. Furnace, electric, 322. G. Galvanic batteries, 493, 494. Galvanometer, 493. mirror, 570. Gas engine, 25. governor, 769. holder, 766. making apparatus, 765. meters, 775. pressure, 769. retorts, 766. 818Gases of blast furnace, 49. Gatling battery gun, or mitrailleur, 219. Gauge, broad and narrow, 106. Bourdon’s pressure, 12. Geissler’s tubes, 505. Ghost, Pepper’s, 392. Giffard’s injector, 11. Girder bridges, 280. Glass, strains in, 407. Glatton, H. M. S., 161. Glynde, electric railway, 534. Gold, 686. Gold and diamonds, 687. Gold-mining operations, 690. Goodyear, Mr., 727. Governor of steam engines, 6. Gower Street Station, 114.