Discoveries and Inventions of the Nineteenth Century - Robert Routledge

Please enable JavaScript to view the full PDF

TORPEDOES 227 SHIP CANALS 249 THE SUEZ CANAL 251 THE MANCHESTER SHIP CANAL 262 THE NORTH SEA CANAL 271 THE PANAMA AND NICARAGUA CANAL PROJECTS 272 IRON BRIDGES 276 GIRDER BRIDGES 280 SUSPENSION BRIDGES 284 CANTILEVER BRIDGES 291 THE TOWER BRIDGE, LONDON 297 THE GREAT BROOKLYN BRIDGE 303 PRINTING MACHINES 305 LETTERPRESS PRINTING 306 PATTERN PRINTING 321 HYDRAULIC POWER 324 PNEUMATIC DISPATCH 340 ROCK BORING 349 THE MONT CENIS TUNNEL 351 ROCK-DRILLING MACHINES 355 THE CHANNEL TUNNEL 364 THE ST. GOTHARD RAILWAY 371 LIGHT 380 SOME PHENOMENA OF LIGHT 382 VELOCITY OF LIGHT 384 REFLECTION OF LIGHT 388 REFRACTION 397 DOUBLE REFRACTION AND POLARISATION 399 CAUSE OF LIGHT AND COLOUR 408 THE SPECTROSCOPE 416 CELESTIAL CHEMISTRY AND PHYSICS 436 ROENTGEN’S X RAYS 445 SIGHT 452 THE EYE 454 VISUAL IMPRESSIONS 468 ELECTRICITY 481 ELEMENTARY PHENOMENA OF ELECTRICITY AND MAGNETISM 483 THEORY OF ELECTRICITY 487 ELECTRIC INDUCTION 488 DYNAMICAL ELECTRICITY 490 INDUCED CURRENTS 502 MAGNETO-ELECTRICITY 507 THE GRAMME MAGNETO-ELECTRIC MACHINE 511 ELECTRIC LIGHTING AND ELECTRIC POWER 519 THE NEW ELECTRICITY 538 THE ELECTRIC TELEGRAPH 547 TELEGRAPHIC INSTRUMENTS 553 TELEGRAPHIC LINES 572 THE TELEPHONE 581 LIGHTHOUSES 593 PHOTOGRAPHY 607 PHOTOGRAPHY IN COLOURS 630 PRINTING PROCESSES 632 STEREOTYPING 632 LITHOGRAPHY 636 OTHER PROCESSES 640 THE LINOTYPE MACHINE 645 RECORDING INSTRUMENTS 653 THE PHONOGRAPH 665 AQUARIA 675 THE CRYSTAL PALACE AQUARIUM 677 THE BRIGHTON AQUARIUM 682 GOLD AND DIAMONDS 687 GOLD 687 DIAMONDS 696 NEW METALS 714 INDIA-RUBBER AND GUTTA-PERCHA 724 INDIA-RUBBER 724 GUTTA-PERCHA 728 ANÆSTHETICS 731 EXPLOSIVES 740 MINERAL COMBUSTIBLES 751 COAL 751 PETROLEUM 757 PARAFFIN 761 COAL-GAS 764 COAL-TAR COLOURS 781 THE GREATEST DISCOVERY OF THE AGE 801 NOTES 811 INDEX 813 LIST OF ILLUSTRATIONS. FIG. PAGE Heading—Rain, Steam, and Speed (after Turner) 1 1. Portrait of James Watt 3 2. Newcomen’s Steam Engine 4 3. Watt’s Double-action Steam Engine 5 4. Governor and Throttle-Valve 6 4a. Watt’s Parallel Motion 8 5. Slide Valve 9 6. Section of Gifford’s Injector 11 7. Bourdon’s Pressure Gauge 12 8. Steam Generator 13 9. Section of Locomotive 15 10. Stephenson’s Link Motion 17 10a. G. N. R. Express Passenger Locomotive 19 10b. Joy’s Valve Gear 20 11. Locomotive after Explosion 22 12. Hancock’s Steam Omnibus 22 13. Nasmyth’s Steam Hammer 27 14. Merryweather’s Steam Fire-Engine 28 15. A Foundry 29 16. Aerolite in the British Museum 31 17. Blast Furnace 41 18. Section and Plan of Blast Furnace (obsolete type) 42 19. Section of a Reverberatory Furnace 45 20. Fibrous Fracture of Wrought Iron 47 21. Cup and Cone 49 22. Section of Blast Furnace 51 23. Experiments at Baxter House 58 24. Bessemer Converter 63 25. Model of Bessemer Steel Apparatus 65 26. Section of Regenerative Stoves and Open Hearth 68 26a. Rolling Mill 71 26b. The Eiffel Tower in course of construction 73 26c. The Eiffel Tower 75 26d. St. Paul Building, N. Y. 77 26e. Manhattan Insurance Co.’s Building in course of erection 79 26f. Manhattan Insurance Co.’s Building nearly completed 80 26g. Original Design for the Great Wheel 82 27. Portrait of Sir Joseph Whitworth 85 28. Whitworth’s Screw Dies and Tap 86 29. Screw-cutting Lathe 87 30. Whitworth’s Measuring Machine 89 31. Whitworth’s Drilling Machine 91 32. Whitworth’s Planing Machine 93 33. Pair of Whitworth’s Planes or Surface Plates 94 34. Interior of Engineer’s Workshop 95 35. Blanchard Lathe 96 36. Vertical Saw 98 37. Circular Saw 99 38. Pit-Saw 100 39. Box Tunnel 101 40. Coal-pit, Salop 102 41. Sankey Viaduct 103 42. Rails and Cramp-gauge 104 43. Fish-plate 105 44. Section of Rails and Fish-plates 106 45. Conical Wheels 107 46. Centrifugal Force 107 47. Points 108 48. Signal Box on North London Railway 109 49. Post Office Railway Van 111 50. Gower Street Station, Metropolitan Railway 115 51. Map of the Route of Pacific Railway 117 52. Trestle Bridge 118 53. American Canyon 119 54. “Cape Horn” 121 55. Snow Plough 122 56. First Steam Railroad Train in America 123 57. Railway Embankment 124 57a. Train ascending the Rigi 126 57b. At the summit of the Rigi 127 58. The Great Eastern at Anchor 129 59. Casting Cylinder of a Marine Steam Engine 131 60. Screw Propeller 132 61. Section of Great Eastern Amidships 134 62. The Great Eastern in course of construction 135 63. The Great Eastern ready for launching 136 64. Comparative sizes of Steamships 137 65. The ss. City of Rome 138 66. The Castalia in Dover Harbour 140 67. The same—End View 141 68. Bessemer Steamer 142 68a. A Whaleback Steamer, No. 85, built at West Superior, Wisconsin 146 69. H.M.S. Devastation in Queenstown Harbour 149 70. Section of H.M.S. Hercules 151 71. Section of H.M.S. Inconstant 153 72. Section, Elevation and Plan of Turret of H.M.S. Captain 154 73. H.M.S. Captain 155 74. Diagram of H.M.S. Captain 158 75. Ditto 159 76. H.M.S. Glatton 162 77. H.M.S. Thunderer 163 78. The König Wilhelm 165 78a. The Victoria leaving Newcastle-on-Tyne 166 78b. Firing at Floating Battery 168 79. Krupp’s Works at Essen, Prussia 169 80. Trajectory of a Projectile 174 81. Diagram for Trajectory of a Projectile 176 82. Muzzle-loading Musket and Rifles (obsolete patterns) 179 83. The Minié Bullet 181 84. Greener’s Expanding Bullet 182 85. The Chassepot Rifle—Section of the Breech 183 86. Section of the Martini-Henry Lock 185 87. The Martini-Henry Rifle 186 88. The Mannlicher Magazine Rifle 188 89. The Magazine and Breech of the Mannlicher Rifle 189 90. 32–pounder, 1807 191 91. Whitworth Rifling and Projectile 193 92. 600–pounder Muzzle-loading Armstrong Gun 194 93. 35–ton Fraser Gun 195 94. Section of 9–in. Fraser Gun 196 95. Millwall Shield after being battered with Heavy Shot—Front View 200 96. Rear View of the Millwall Shield 200 97. Comparative Sizes of 35 and 81–ton Guns 201 98. Diagram of Velocities and Pressures 205 99. Elswick 4·7–in. Q. F. Gun on Pivot Mounting 207 100. The Moncrieff Gun raised and ready for firing 209 101. Moncrieff Gun lowered for loading 209 102. 68–ton Gun on Elswick Hydro-Pneumatic Mounting 211 103. Mallet’s Mortar 213 104. 32–pounder Krupp Siege Gun, with Breech-piece open 214 105. The Citadel of Strasburg after the Prussian Bombardment 215 105a. The Shrapnel and Segment Shells 217 105b. The Gatling Gun—Rear View 219 105c. The Gatling Gun—Front View 221 105d. The Montigny Mitrailleur 222 105e. A Hotchkiss Gun 224 106. Harvey’s Torpedo.—Working the Brakes 227 107. Submerged Torpedo 228 108. Mode of Firing Torpedo 230 109. Explosion of Whitehead’s Torpedo 231 110. Effect of the Explosion of Whitehead’s Torpedo 232 111. Experiment with a Torpedo charged with 10 lbs. Gun Cotton 233 112. Explosion of Torpedo containing 67 lbs. Gun Cotton 234 113. Explosion of 432 lbs. Gun Cotton in 37 ft. Water 235 114. The same in 27 ft. Water 235 115. Section of Priming Case and Exploding Bolt 236 116. Harvey’s Torpedo 237 117. The same 238 118. The same 239 119. Official Trial of “Harvey’s Sea Torpedo” 239 120. Model of Submarine Guns 240 121. The Warner Experiment off Brighton 241 122. Portrait of M. Lesseps 249 123. The Sand-Glass 253 124. A Group of Egyptian Fellahs and their Wives 254 125. Dredges and Elevators at Work 255 126. Map of the Suez Canal 256 127. Port Saïd, the Mediterranean Entrance to the Suez Canal 257 128. Bird’s-eye View of Port Saïd 258 129. One of the Breakwaters at Port Saïd 259 130. Lake Timsah and Ismaïlia 259 131. Railway Station at Ismaïlia 260 132. The Viceroy of Egypt cutting Embankment 261 133. Map of the Manchester Ship Canal, Western Portion 263 134. Map of the Manchester Ship Canal, Eastern Portion 263 135. A Cutting for the Manchester Ship Canal 265 136. Blasting Rocks for the Manchester Ship Canal 266 137. Manchester Ship Canal Works, Runcorn 267 137a. The French Steam Navvy 268 137b. The English Steam Navvy 269 137c. Sketch Map of the North Sea Canal 271 138. Britannia Bridge, Menai Straits 276 139. Diagram showing Strains 278 140. Ditto 279 141. Girder 279 142. Ditto 279 143. Ditto 280 144. Section of a Tube of the Britannia Bridge 281 145. Albert Bridge, Saltash 283 146. Clifton Suspension Bridge, near Bristol 285 147. Section of Shaft 286 147a. Clifton Suspension Bridge, Niagara 288 147b. Living Model of the Cantilever Principle 291 147c. Principal Dimensions of the Forth Bridge 294 147d. Map of the Tower Bridge and its Approaches 299 147e. The Tower Bridge 301 147f. Sketch 302 148. Newspaper Printing-Room 305 149. Inking Balls 306 150. Inking Roller 306 151. Diagram of Single Machine 308 152. Diagram of Perfecting Machine 309 153. Cowper’s Double Cylinder Machine 309 154. Tapes of Cowper’s Machine 310 155. Hopkinson and Cope’s Perfecting Machine 311 156. Section of Casting Apparatus 314 157. Diagram of the Walter Press 315 158. Hoe’s Type Revolving Cylinder Machine 317 159. Hoe’s “Railway” Machine 319 160. Napier’s Platen Machine 320 161. Roller for Printing Wall-Papers 322 162. Machine for Printing Paper-Hangings 323 163. Chain Testing Machine 324 164. Pascal’s Principle 325 165. Collar of Hydraulic Cylinder 326 166. Hydraulic Press 327 167. Section of Hydraulic Lift Graving Dock 331 168. Section of Column 332 169. Sir W. Armstrong’s Hydraulic Crane 335 170. Raising Tubes of Britannia Bridge 336 171. Press for Raising the Tubes 337 172. Head of Link-Bars 338 173. Apparatus to Prove Transmission of Pressure 339 174. Pneumatic Tubes and Carriages 340 175. Diagram of Tubes, &c. 342 176. Sending and Receiving Apparatus 343 177. Section of Receiving Apparatus 344 178. Sommeiller Boring Machines 349 179. Transit by Diligence over Mont Cenis 353 180. Burleigh Rock Drill on Tripod 356 181. The same on Movable Column 358 182. The same Mounted on Carriage 359 183. Diamond Drill Crown 360 184. Diamond Drill Machinery 363 185. Chart of the Channel Tunnel 367 186. Section of the Channel Tunnel 368 187. View of Dover 369 187a. Map of the St. Gothard Railway 372 187b. The Uppermost Bridge over the Maïenreuss 375 187c. The Bridges over the Maïenreuss, near Wasen 377 187d. Windings of the Line near Wasen 378 188. Contrasts of Light 380 189. Rays 382 190. Diagram 383 191. Telescopic Appearance of Jupiter and Satellites 384 192. Diagram 386 193, 194, Diagrams 388 195. 196. Diagram 389 197. Polemoscope 390 198. Apparatus for Ghost Illusion 391 198a. The Ghost Illusion 393 199. Illusion produced by Mirrors 394 200. A Stage Illusion 395 201. View of Venice—Reflections 396 202. Refraction 397 203. Diagram 398 204, 205. Diagrams of Crystals 400 206. Diagram 401 207. Diagram 403 208. Diagram 404 209. Polariscope 406 210. Section showing Polarisation 407 211. Iceland Spar, showing Double Refraction 407 212. Diagram 408 213. Diagram 410 214. Diagram 412 215. Portrait of Professor Kirchhoff 416 216. Diagram 417 217. Newton’s Experiment 418 218. Bunsen’s Burner on Stand 421 219. Spectroscope with one Prism 423 220. Miniature Spectroscope 426 221. The Gassiot Spectroscope 427 222. Browning’s Automatic Adjustment of Prisms 429 223. Apparatus for Spark Spectra 430 224. The Sorby-Browning Micro-Spectroscope 433 225. Section of Micro-Spectroscope, with Micrometer 434 226. Diagram 435 227. Section of Micro-Spectroscope 436 228. Solar Eclipse, 1869 439 229. The Planet Saturn 441 230. Solar Prominences, No. 1 442 231. Ditto, No. 2 443 232. Section of Amateur Star Spectroscope 444 232a. X. Ray Photo of Living Hand, Exposure 4 minutes 446 232b. Skiagraph of a Hand by Dr. Roentgen 448 232c. Metal objects photographed through Calico and sheet of Aluminium 450 232d. Skiagraph of Layers of various substances 451 233. Portrait of Professor Helmholtz 452 234. Vertical Section of the Eye 454 235. Section of Retina 456 236. Diagram 457 237. Muscles of Eyes 459 238. Diagram 461 239. Diagram 464 240. Diagram 465 241. Ruete’s Ophthalmoscope 466 242. Diagram 467 243. Wheatstone’s Reflecting Stereoscope 469 244. Diagram 470 245. Diagram 471 246. The Telestereoscope 473 247. Lines 475 248, 249. Diagrams 476 250, 251. Diagrams 477 251a. Edison’s Kinetographic Theatre 479 252. Portrait of Sir W. Thomson 481 253. A simple Electroscope 485 254. The Gold-leaf Electroscope 489 255. The Leyden Jar 490 256. A Voltaic Element 491 257. Ampère’s Rule 492 258. Galvanometer 493 259. Daniell’s Cell and Battery 495 260. Grove’s Cell and Battery 495 261. Wire Ignited by Electricity 496 262. Duboscq’s Electric Lantern and Regulator 497 263. Decomposition of Water 498 264. Electro-plating 499 265. A Current producing a Magnet 500 266. An Electro-magnet 501 267. Ruhmkorff’s Coil 503 268. Discharge through Rarefied Air 504 268a. Large Induction Coil at the Old Polytechnic Institution, London 505 269. Appearance of Spark on Looking-glass 507 270. Magneto-electric Spark 508 271. A Magnet producing a Current 509 272. Clarke’s Magneto-electric Machine 509 273. Magneto-electric Light 510 274. Diagram 511 275. Gramme Machine 512 276. Insulated Coils 513 277. Hand Gramme Machine 513 278. Gramme Machine, with eight Vertical Electro-Magnets 516 279. Gramme Machine, with Horizontal Electro-magnets 517 280. Gramme Machine 519 280a. The Alliance Machine 520 280b. Wilde’s Machine 521 280c. Siemens’ Dynamo 522 280d. The Brush Dynamo 523 280e. Siemens’ Regulator 524 280f. Jablochkoff Candle 525 280g. Electric Lamp 526 280h. Incandescent Lamp 529 280i. Poles with Single Arms for Suburban Roads.—The Ontario Beach Railway, 533 Rochester, N.Y. 280j. The Glynde Telepherage Line, on the system of the late Fleeming Jenkin 534 280k. Diagrams 540 280l. The Tesla Oscillator 542 280m. M. Nikola Tesla 543 281. Portrait of Professor Morse 547 282. Double-Needle Instrument 554 283. Electro-magnetic Bells 555 284. Portable Single-Needle Instrument 556 285. Connections of Telegraph Line 558 286. Morse Recording Telegraph 559 287. Morse Transmitting Key 561 288. Morse Transmitting Plate 562 289. Step-by-step Movement 567 290. Froment’s Dials 567 291. Wheatstone’s Universal Dial Telegraph 568 292. Mirror Galvanometer 571 293. Telegraph Post and Insulators 573 294. Ditto 573 295. Wire Circuit 574 296. Wire and Earth Circuit 574 297. Submarine Cable 575 298. Making Wire for Atlantic Cable 577 299. Instrument Room at Valentia 578 300. Breaking of the Cable 579 301. Atlantic Telegraph Cable, 1866 580 302. Diagram 580 302a. Reiss’s Musical Telephone 584 302b. Bell’s Musical Telephone 585 302c. Superposition of Currents 587 302d. Bell’s Speaking Telephone 588 302e. Hughes’s Microphone 591 Lighthouse (heading) 593 303. Eddystone Lighthouse 594 304. Eddystone in a Storm 595 305. Revolving Light Apparatus 601 306. Stephenson’s Holophotal Light 604 307. Camera 607 308. Camera and Slide 615 309. Folding Camera 616 310. Lenses 617 311. Bath 619 311a. The Roll-Slide 622 312. Portrait of Aloysius Senefelder 632 313. Press for Stereotyping by Clay Process 633 313a. The Linotype Machine 645 313b. A Matrix 646 313c. Diagram of Movements 647 313d. A Line of Matrices 648 313e. A finished Line entering galley 649 313f. The Melting Pot and Mould Wheel 650 313g. The Finished Line 651 313h. Lines assembled into a “Form” 651 313i. Matrices dropping into Magazine 652 314. Recording Anemometer 653 315. Registration of Height of Barometer and Thermometer 655 316. Electric Chronograph 657 317. Negretti’s Deep-Sea Thermometer 661 318. Ditto, General Arrangement 662 319. Atmospheric Recording Instrument 663 319a. Traces of Vibrations of a Tuning-Fork 667 319b. Phonautographic Tracings of Different Vowel Sounds 667 319c. Diagram 668 319d. Phases of Sound Waves 668 319e. Edison’s Original Phonograph 670 319f. Diagrammatic Section of Phonograph 671 319g. The Graphophone 672 319h. Edison’s Perfected Phonograph 674 320. Domestic Aquarium 675 321. The Opelet 679 322. Viviparous Blenny 680 323. The Lancelet 681 324. Sea-Horses 683 325. Proteus anguinus 684 326. Mud-Fish 685 327. The Axolotl 686 328. Sorting, Washing, and Digging at the South African Diamond Fields 687 329. Gold Miner’s Camp 689 330. Gold in Rocks 690 331. “Cradle” for Gold-washing 690 332. Pniel, from Jardine’s Hotel 702 333. Sifting at the “Dry Diggings” 703 334. Vaal River, from Spence Kopje 704 334a. Sketch Section of the Kimberley Diamond Mine 709 335. Portrait of Sir Humphrey Davy 714 336. Apparatus 717 337. Portrait of Mr. Thomas Hancock 724 338. Portrait of Sir James Young Simpson, M.D. 731 339. Railway Cutting 740 340. View on the Tyne 751 341. Fossil Trees in a Railway Cutting 752 342. Impression of Leaf in Coal Measures 753 343. Possible Aspect of the Forests of the Coal Age 754 344. The Fireside 756 345. View on Hyde and Egbert’s Farm, Oil Creek 761 346. View of City of London Gas-Works 764 347. Section of Gas-making Apparatus 765 348. The Retort 767 348a. Retort House of the Imperial Gas-Works 768 349. The Gas Governor 770 350. Bunsen’s Burner 772 351. Faraday’s Ventilating Gas-Burner 773 351a. Diagram 778 351b. Diagram 778 351c. Diagram 779 351d. Diagram 779 351e. Diagram 780 352. Apparatus for making Magenta 781 353. Iron Pots for making Nitro-Benzol 784 354. Section of Apparatus for making Nitro-Benzol 785 355. Apparatus for making Aniline 786 356. Section of Hollow Spindle 787 357. Portrait of J. Prescott Joule, F.R.S. 801 LIST OF PLATES. PLATE I. TO FACE THE GREAT WHEEL IN ACTION Title page PLATE II. NORTH-EASTERN RAILWAY LOCOMOTIVE 18 PLATE III. THE GREAT STEAM HAMMER, ROYAL GUN FACTORY, WOOLWICH 28 PLATE IV. THE AMERICAN TRACT SOCIETY BUILDING 76 PLATE V. GENERAL VIEW OF THE GREAT WHEEL AT EARL’S COURT 84 PLATE VI. MOUNT WASHINGTON INCLINED TRACK 124 PLATE VII. PIKE’S PEAK RAILROAD, ROCKY MOUNTAINS 128 PLATE VIII. THE “CLERMONT” FROM A CONTEMPORARY DRAWING 130 PLATE IX. THE “MARY POWELL” 144 PLATE X. THE “NEW YORK” 148 PLATE XI. H.M.S. “THE TERRIBLE” 168 PLATE XII. THE 110–TON ARMSTRONG GUN 202 PLATE XIII. THE FORTH BRIDGE 292 PLATE XIV. THE TOWER BRIDGE IN COURSE OF CONSTRUCTION 298 PLATE XV. THE BROOKLYN BRIDGE 304 PLATE XVI. THE NORTH MOUTH OF THE GREAT TUNNEL, ST. GOTHARD RAILWAY 374 PLATE XVII. SPECTRA (Coloured Plate) 422 Wind, Steam, and Speed (after TURNER). INTRODUCTION. Only by knowledge of Nature’s laws can man subjugate her powers and appropriate her materials for his own purposes. The whole history of arts and inventions is a continued comment on this text; and since the knowledge can be obtained only by observation of Nature, it follows that Science, which is the exact and orderly summing-up of the results of such observation, must powerfully contribute to the well-being and progress of mankind. Some of the services which have been rendered by science in promoting human welfare are thus enumerated by an eloquent writer: “It has lengthened life; it has mitigated pain; it has extinguished diseases; it has increased the fertility of the soil; it has given new securities to the mariner; it has furnished new arms to the warrior; it has spanned great rivers and estuaries with bridges of form unknown to our fathers; it has guided the thunderbolt innocuously from heaven to earth; it has lighted up the night with the splendour of the day; it has extended the range of the human vision; it has multiplied the power of the human muscles; it has accelerated motion; it has annihilated distance; it has facilitated intercourse, correspondence, all friendly offices, all dispatch of business; it has enabled man to descend to the depths of the sea, to soar into the air, to penetrate securely into the noxious recesses of the earth, to traverse the land in cars which whirl along without horses, to cross the ocean in ships which run ten knots an hour against the wind. These are but a part of its fruits, and of its first-fruits; for it is a philosophy which never rests, which has never attained, which is never perfect. Its law is progress. A point which yesterday was invisible is its goal to-day, and will be its starting-point tomorrow.”—(MACAULAY). Thus every new invention, every triumph of engineering skill, is the embodiment of some scientific idea; and experience has proved that discoveries in science, however remote from the interests of every-day life they may at first appear, ultimately confer unforeseen and incalculable benefits on mankind. There is also a reciprocal action between science and its application to the useful purposes of life; for while no advance is ever made in any branch of science which does not sooner or later give rise to a corresponding improvement in practical art, so on the other hand every advance made in practical art furnishes the best illustration of scientific principles. The enormous material advantages which this age possesses, the cheapness of production that has placed comforts, elegancies, and refinements unknown to our fathers within the reach of the humblest, are traceable in a high degree to the arrangement called the “division of labour,” by which it is found more advantageous for each man to devote himself to one kind of work only; to the steam engine and its numerous applications; to increased knowledge of the properties of metals, and of the methods of extracting them from their ores; to the use of powerful and accurate tools; and to the modern plan of manufacturing articles by processes of copying, instead of fashioning everything anew by manual labour. Little more than a century ago everything was slowly and imperfectly made by the tedious toil of the workman’s hand; but now marvellously perfect results of ingenious manufacture are in every-day use, scattered far and wide, so that their very commonness almost prevents us from viewing them with the attention and admiration they deserve. Machinery, actuated by the forces of nature, now performs with ease and certainty work that was formerly the drudgery of thousands. Every natural agent has been pressed into man’s service: the winds, the waters, fire, gravity, electricity, light itself. But so much have these things become in the present day matters of course, that it is difficult for one who has not witnessed the revolution produced by such applications of science to realize their full importance. Let the young reader who wishes to understand why the present epoch is worthy of admiration as a stage in the progress of mankind, address himself to some intelligent person old enough to remember the century in its teens; let him inquire what wonderful changes in the aspect of things have been comprised within the experience of a single lifetime, and let him ask what has brought about these changes. He will be told of the railway, and the steam-ship, and the telegraph, and the great guns, and the mighty ships of war— “The armaments which thunderstrike the walls Of rock-built cities, bidding nations quake, And monarchs tremble in their capitals.” He will be told of a machine more potent in shaping the destinies of our race than warlike engines—the steam printing-press. He may hear of a chemistry which effects endless and marvellous transformations; which from dirt and dross extracts fragrant essences and dyes of resplendent hue. He may hear something of a wonderful instrument which can make a faint beam of light, reaching us after a journey of a thousand years, unfold its tale and reveal the secrets of the stars. Of these and of other inventions and discoveries which distinguish the present age it is the purpose of this work to give some account.