JjONDON WALTON AND MABERLY, UPPER GOWEE STREET & IVY LANE. Price Eighteenpenoe. 52ESH5H5SE5H5HSH525H5H5E5E525E5HS5H5H5d5 ^ LIBRARY UNIYCR ITY OP I CAUPORNIAy EDITED BY DIONYSIUS LAEDNEE, D.C.L., Formerly Professor of Natural Philosophy and Astronomy in University College, London. ILLUSTRATED BY ENGRAVINGS ON WOOD. YOL. IV. LONDON : WALTON AND MABERLY, UPPER GOWER STREET AND IVY LANE, PATERNOSTER ROW. 1854. LOAN STACK LONDON : BRADBVBY AND EVANS, PKJSTKHS, WUITEVEIAKS. '0171 L37 CONTENTS. THE ELECTRIC TELEGRAPH. i CHAP. VII. 163. Momentary currents alternately in contrary directions. 164. Method of producing momentary currents all in the same direction. 165. Magneto-electric machine. 166. Its effects in producing shocks and currents. 167. Method of applying it to telegraphs. 168. Chemical property of the current. 169. Decomposition of water. 170. Application of this property to produce written characters at a distance. 171. Methods of moving the paper under the style. 172. Telegraphic characters marked upon it. 173. Use of relay magnets in cases of feeble currents. 174. Form and application of them. 175. Telegraphic lines constructed by companies in England and America, and chiefly by the state on the continent. 176. Various forms of instruments used. 177. Influence of national feeling. 178. Meritorious inventions sometimes neglected. 179. Needle instruments generally used in England. 180. Single needle instrument. 181. Double needle instrument. 182. Old aerial telegraph. 183. French State telegraph .... CHAP. VIII. 184. Form of commutator of French state telegraph. 185. Its opei'ation. 186. Method of sending and receiving a dispatch. 187. Batteries. 188. French railway telegraph. 189. French railway portable telegraph. 190. German railway telegraph. 191. Siemens' instrument. 192. Its mode of operation. 193. How errors are corrected. 194. Explanation of the mechanism. 195. Comparison with the French telegraph. 196. Indicating mechanism. 197. Simplicity greater than the French instrument. 198. Requires greater intensity of current. 199. Belgian railway telegraph. 200. Defects im- puted to the French and German instrument ."'.'. . 17 CHAP. IX. 201. Defects of the French and German instrument removed by Lippens' instrument. 202. Description of it. 203. Its wheel commutator. 204. Transmission of dispatches by it. 205. Froment's alphabetic telegraph. 206. Morse's tele- graph. 207. Froment's writing telegraph. 208. Bain's chemical telegraph. 209. Method of writing. 210. Electro-chemical .pen. 211, Metallic desk 33 378 i v CONTENTS. CHAP. X. 212. Operation of Bain's telegraph. 213. _ Its com- mutator. 214. Its extraordinary speed of transmission. 215. Obstructions to its practical application. 216. Its prospects. 217. Autograph telegraph. 218. House's printing telegraph 219. Its operation.- 220. Henley's magnetic telegraph. 221. Brett's printing telegraph. 222. Celerity of telegraphic com- munication. 223. Circumstances which affect it. 224. Com- parative ability of telegraphists. 225. Each telegi'aplnst known by his manner of transmitting. 226. Easier to transmit than to receive. 227. Pauses in transmission. 228. Kate of trans- mission with double needle instruments woiked by voltaic current. 229. Rate with magneto-electric current . . . .49 CHAP. XI. 230. Illustration of the efficiency of the needle instru- ments. 231. Rate of transmission with the French state tele- graphs. 232. With the French railway telegraphs. 233. With the Morse telegraph. 234. Discrepancy of leports. 235. Causes of its celerity. 236. Rate with Bain's telegraph. 237. Trans- mission of music. 238. Rate of transmission with House's telegraph. 239. Distance sometimes affects celerity. 240. Examples of distant transmissions in U. S. 241. Advantages of uniform organisation. 242. Uses of the electric telegraph. 243. Subject of dispatches. 214. Effect of the tariff. 245. Uses of the telegraph in railway business. 246. Portable railway telegraph. 247. Practical uses on railways. 248. Its economical advantages .< .' . -. : * . . 65 CHAP. XII. 249. Prevention of accidents. 250. Its uses in the detection of crime. 251. Personal and domestic messages. 252. Electric news-rooms. 253. Telegraph extensively used in the United States. 254. Much used for commerce. 255. Sums paid for telegraphic dispatches by mercantile firms. 256. Extensively used by American newspapers. 257. Illustration of the utility for political purposes. 258. Illustrations of its domestic and general use. 259. Secrecy of dispatches not gene- rally sought for. 260. Verbal ciphers of mercantile firms. 261. Ciphers for newspaper reports. 262. Association of New York journals. 263. Spirited enterprise of New York ' ' Herald.'' 264.' Use of electric telegraph in determining longitudes. 265. In producing horological uniformity . . . .81 CHAP. XIII. 266. Signal time balls. 267. Electric connection of observatories of Greenwich, Brussels, and Paris. 268. Uses of electric telegraph in astronomical observations. 269. In regulating the observatory clocks, 270. In fixing with pre- cision the time of an astronomical phenomenon. 271. Telegraphic lines of the United Kingdom. 272. Their extent in 1854. 273. Electric Telegraph Company. 274. Table of its lines, stations, &c. 275. Present Tariff (1854) 97 CONTENTS. CHAP. XIV. Electric Telegraph Company's present tariff (continued). 276. Magnetic Telegraph Company. 277. Chartered Sub- marine Company. 278. The Submarine Telegraph Company between France and England. 279. European and American Telegraph Company. 280. Origin of the submarine companies' enterprises. 281. Wonderful celerity of international cor- respondence. 282. Organisation of electric communications with the Continent. 283. Mediterranean Electric Telegraph Company. 284. General table showing the places on the con- tinent of Europe, which are in electric connection with each other, and with England, and the cost of dispatches sent between them severally and London. 285. Telegraphic lines iu the United States. 286. Vast projects in progress or contem- plation V". 1 - H3 CHAP. XV. 287. Telegraphic lines in British America. 288. Belgian lines. 289. Their extent and cost. 290. Correspondence transmitted on them. 291. Large proportion of foreign dispatches. 292. Classification and proportion of dispatches. 293. Tariff. 294. Paris telegraphic congress and convention. 295. Tele- graphic instruments used in Belgium. 296. Language of dis- patches. 297. French telegraphic lines. 298. Instruments used on them. 299. Their connection with those of other states. 300. Repetition necessary at intermediate stations. 301. Case of dispatches between France and England. 302. Advantages of increased number of wires. 303. Of instruments requiring only one wire. 304. Organisation of the French telegraphic adminis- tration. 305. Austro-Gfermanic Union. 306. Stations and tariff. 307. Netherlands telegraphic lines. 308. Swiss tele- graphic lines. 309. Italian telegraphic lines 129 EARTHQUAKES AND VOLCANOES. CHAP. I. 1. Science tends to the discovery of general laws admits no accidental phenomena. 2. Atmospheric phenomena neither uncertain nor accidental. 3. Physical subterranean agencies. 4. Convulsions incidental to the solid shell of the earth. 5. Increase of temperature at increasing depths. 6. Central parts in a state of fusion. 7. Depth at which this liquid state com- mences. 8. Proportional thickness of the solid shell. 9. Surface of the earth subject to frequent convulsions from the reaction of the internal fluid matter on the solid shell. 10. Geological evidences of this. 11. Physical causes of earthquakes and volcanoes. 12. Undulations of surface produced by the internal fluid. 13. Their effects on buildings and other objects. 14. Vertical and oscillatory motions. 15. Undulations propa- gated in parallel lines sometimes in circles. 16. Effects of the vertical shock in the earthquake of Riobamba. 17. Examples of circular propagation. 18. Examples of horizontal and gyratory derangement. 19. Strong shocks sometimes felt without over- turning buildings. 20. Gyratory earthquakes most destructive. vi CONTENTS. PAGE 21. Singular displacement at Riobamba. 22. Earthquakes are not generally attended by any peculiar atmospheric prognostics. 23. Earthquakes most frequent at the equinoxes. 24. Well described by Pliny and Seneca. 25. Attended by subterranean thunder. 26. Character of these sounds. 27. Are heard at great distances from the place of the earthquake. 28. Examples of this. 29. Subterranean roaring of Guanxauato. 30. Their effects on the inhabitants 31. Great extent over which earth- quakes spread. 32. They affect the bottom of the ocean. 33. Curious examples of these effects . . . . . .145 CHAP. II. 34. Earthquakes at Jamaica. 35. Extent of the Lisbon earthquake. 36. Long continuance of slight earthquakes. 37. They affect all kinds of strata. 38. They sometimes pass over certain districts called bridges. 39. Inferior strata are sometimes agitated when the superficial strata are undisturbed. 40. Inferior strata sometimes undisturbed when superficial strata are agitated. 41. Undulations often, but not always, move parallel to mountain chains. 42. Humboldt's description of the effects of earthquakes. 43. Number of earthquake-shocks in England. 44. Ejection of matter from the interior of the earth. 45. Temperature of water in Artesian wells. 46. Temperature indicates depth. 47. Natural thermal springs. 48. Independent of strata. 49. Their occasional permanency the classic fountains still flow. 50. From certain depths vapour only rises. 51. Also certain gases Artesian fire- wells. 52. Carbonic acid its effects in former states of the globe origin of coal beds. 53. And marbles. 54. Mud volcanoes. 55. Those of remote origin. 56. Progressive development. 57. Formation of dome-shaped mountains. 58. Crater of elevation. 59. Active volcanoes. 60. Successive stages of their formation. 61. Not uniformly or permanently active. 62. Intervals of activity and repose. 63. Dependent on the height. 64. Stromboli. 65. Guacamayo. 66. Volcanoes of the Andes. 67. Exceptions explained. 68. Eruptions often lateral. 69. Groups of small cones. 70. Re- markable spectacle of Cotopaxi. 71. View of an active crater. 72. Eemarkable permanence of the form of craters. 73. Effects of snow-capped cones. 74. Cause of the fiery appearance of ejected matter. 75. Islands of volcanic origin. 76. Volcanic theories 161 THE BAROMETER. 1. Origin of the name. 2. Conditions necessary to render the instru- ment useful. 3. To purify the mercury. 4. To cleanse the tube. 5. To fill the tube. 6. To invert it in the cistern. 7. Con- struction of a barometer. 8. Effect of temperature on the barometric column. 9. To ascertain if the vacuum above the column be perfect. 10. Expedients to render minute variations of altitude visible. 11. Diagonal barometer. 12. Wheel barometer. 13. Common siphon barometer. 14. Use of the CONTENTS. barometer to measure heights. 15. Density of strata affected by their temperature. 16. Fall of barometer in the balloon ascent of Gay Lussac. 17. Extreme variations of the barometric column in a given place. 18. Its diurnal variation. 19. How- it may prognosticate the weather. 20. Fallacy of popular rules. 21. Barometric prognostics 177 THE SAFETY LAMP. 1. Introductory observations. 2. Fire-damp Sir Humphry Davy invents the Safety Lamp. 3. Nature and laws of flame investigated and discovered by him, and rendered subservient to his invention. ......... 188 WHITWORTH'S MICROMETRIC APPARATUS . .190 STEAM. 1. Power of steam manifested by natural evaporation. 2. Early attempts at its mechanical application Inventions of Watt. 3. Influence of steam power on mankind. 4. Its agency in commerce and the arts. 5. Analysis of its operation. 6. Com- bustion of coals. 7. Force developed by the evaporation of water. 8. Steam an invisible aeriform fluid. 9. Measure of the mechanical force developed. 10. Heat absorbed in evaporation. 11. Latent heat of steam. 12. Effect of varying pressure. 13. Mechanical force independent of the pressure. 14. Force developed by expansion. 15. Force developed by condensation. 16. Application of these three forces in steam engines. 17. Steam may act variously on piston. 18. Furnaces and boilers. 19. Evaporating power of fuel. 20. Means of economising heat. 21. Prevention of loss by radiation. 22. Inspection and reports of Cornish engines. 23. Greatly improved efficiency. 24. Actual mechanical virtue of coals. 25. Illustra- tions Pyramids of Egypt. 26. Menai Bridge. 27. Railway engines. 28. Exhaustion of coal mines improbable. 29. Prospects of scientific discovery . - -f ' . . . . 193 Fig. 64. MAGNETO-ELECTRIC MACHINE. THE ELECTRIC TELEGRAPH. CHAPTER VII. 163. Momentary currents alternately in contrary directions. 164. Method of producing momentary currents all in the same direction. 165. Magneto-electric machine. 166. Its effects in producing shocks and currents. 167. Method of applying it to telegraphs. 168. Chemical property of the current. 169. Decomposition of water. 170. Application of this property to produce written characters at a distance. 171. Methods of moving the paper under the style. 172. Telegraphic characters marked upon it. 173. Use of relay magnets in cases of feeble currents. 174. Form and application of them. 175. Telegraphic lines constructed by companies in England and America, and chiefly by the state on the continent. 176. Various forms of instruments used. 177. Influence of national feeling. 178. LARDNER'S MUSEUM OP SCIENCE. B No. 41. THE ELECTRIC TELEGRAPH. Meritorious inventions sometimes neglected. 179. Needle instruments generally used in England. 180. Single needle instrument. 181. Double needle instrument. 182. Old aerial telegraph. 183. French State telegraph. 163. THE momentary currents in the one direction or in the other will, therefore, be produced upon the wire connected with the extremities of the coil, such as have already been described, each time the poles, :N T and s, are presented to and withdrawn from the ends, a and 6, of the horse-shoe of soft iron. If the magnet, N o s, were mounted so as to revolve upon an axis passing through the centre of its bend, and therefore midway between its legs, its poles might be made to pass the ends of the horse-shoe, the latter being stationary. During each revolution of the magnet, K o s, the polarity imparted to the horse-shoe would be reversed. When the pole N approaches b, and consequently s approaches a, south polarity will be imparted to &, and north polarity to a ; and when N passes a, and consequently s passes &, south polarity will be imparted to a, and north polarity to b. The momentary currents produced by these changes of mag- netism in a and b will be easily understood by what has been explained. When N approaches &, and s approaches a, the com- mencement of south polarity in 5, and north polarity in a, will both impart to the wire a current in the same direction, because the coils of the spiral as presented to s will be the reverse of those presented to N. When N departs from 6, and s from a, the cessation of south polarity in 6, and of north polarity in , will impart currents in the same direction to the wire, but this direction will be opposite to that of the former currents. When N approaches a, and consequently s approaches 5, cur- rents will be imparted to the wire whose direction will be the same as that of those produced by the departure of js from b, and of s from a. When N departs from a, and s from b, currents will be produced in the same direction as when K approaches b and s approaches a. If the direction of the currents produced when N approaches b, and s approaches a, be indicated by an arrow directed to the right, and that of those produced when N departs from b, and s from a, by an arrow directed to the left, the changes of direc- tion which take place in each revolution of the magnet N o c, will be such as are indicated in fig. 63, where b and a represent the ends of the horse-shoe, b a ; IT the position of the pole in approaching, and N' in departing from b, and u ff its position in approaching, and y ff in departing from a. The arrows directed to the right express the direction of the two 2 MAGNETO-ELECTRIC INSTRUMENT. currents which are produced upon the conducting wire, while N makes the half revolution N'" M' N ; and the arrows directed to Fig. 63. M, \ M' left express the direction of the two currents produced, while sr makes the half revolution N' M N". Thus it appears that in each revolution of the magnet, N o s, four momentary currents are produced in the wire, two in one direction during one semi-revolution, and two in the contrary direction during the other semi-revolution. In the intervals between these momentary currents there is a suspension of voltaic action. 164. It has been already shown how electric currents may be instantaneously suspended, re-established, and reversed in their direction by means of commutators (111). By such an expedient properly adapted, it is easy to understand that by suspending the currents in one of the two contrary directions, while the other is allowed to pass, an intermitting current always running in the same direction may be obtained. Or if the commutator be so adapted that while the momentary currents in one direction are allowed to run without interruption, those in the other direction shall be reversed, we shall then have in each revolution four momentary currents flowing in a common direction. The current thus produced will be intermitting, that is, it will pass upon the., wire by a succession of pulsations or intervals of transmission and suspension, but since in each revolution of the magnet there are two pulsations, that is, two intervals of transmission and two of B 2 3 THE ELECTRIC TELEGRAPH. suspension, and since the rotation of the magnet may be made with any desired rapidity, it follows that the pulsations will succeed each other with such celerity, and the intervals of suspension will be so brief that for all practical purposes the current will be continuous. 165. Such are the principles on which is founded the construction of magneto-electric machines, one form of which is represented in fig. 64 (page 1). The purpose of this apparatus is to produce by magnetic induction an intermitting current constantly in the same direction, and to contrive means by which the intervals of inter- mission shall succeed each other so rapidly that the current shall have practically all the effects of a current absolutely continuous. A powerful compound horse-shoe magnet, A, is firmly attached by bolts and screws upon a horizontal bed, beyond the edge of which its poles a and b extend. Under these is fixed an electro- magnet x Y, with its legs vertical, and mounted so as to revolve upon a vertical axis. The covered wire is coiled in great quantity on the legs x Y, the direction of the coils being reversed in* passing from one leg to the other. The two extremities of the wire proceeding from the legs x and Y are pressed by springs against the surfaces of two rollers, c and dj fixed upon the axis of the electro-magnet. These rollers them- selves are in metallic connection with a pair of handles p and M", to which the current evolved in the wire of the electro-magnet x Y will thus be conducted. If the electro -magnet x Y be now put in rotation by the handle m, the handles P and N being connected by any continuous con- ductor, a system of intermitting and alternately contrary currents will be produced in the wire and in the conductor by which the handles p and N are connected. But if the rollers c and d are so contrived that the contact of the ends of the wire, with them shall be only maintained during a semi-revolution in which the intermitting currents have a common direction, or so that the direction during the other semi-revolution shall be reversed, then the current transmitted through the conductor connecting the handles P and N" will be intermitting, but not contrary ; and by increasing the velocity of rotation of the electro -magnet x Y, the intervals of intermission may be made to succeed each other with indefinite celerity, and the current will thus acquire all the character of a continuous current. The forms of commutators by which the rollers c and d are made to break the contact, and re-establish it with the necessary regularity and certainty, or to reverse it during the alternate semi-revolutions are various. 166. All the usual effects of voltaic currents may be produced 4 ELECTRO-CHEMICAL EFFECTS. with this apparatus. If the handles P and N be held in the hands, the arms and body become the conductor through which the current passes from P to if . If x Y be made to revolve, shocks are felt, which become insupportable when the current has a certain intensity. If it be desired to give local shocks to certain parts of the body, the hands of the operator, protected by non-conducting gloves, direct the knobs at the ends of the handles to the parts of the body between which it is desired to produce the voltaic shock. 167. For telegraphic purposes it will be sufficient to place the line wire in connection with one of the handles P or N, while the other handle is in connection with the earth. A current will then be transmitted on the line wire which will be intermitting, but which may be rendered continuous by a combination of magneto- electric machines. 168. It remains, in fine, to show how the chemical properties of the electric current can be made to supply the means of trans- mitting signals between two distant stations. When a current of adequate intensity is made to pass through certain chemical compounds it is found that these are decomposed, one of their constituents being carried away in the direction of the current, and the other in the contrary direction. 169. One of the most striking examples of the application of this principle is presented in the case of water, which, as is well known, is a compound of the gases called oxygen and hydrogen. Let us suppose that a series of cups, oh, fig.6o, containing water are placed so that an electric current shall pass successively through them, commencing at the wire P and passing at o into the first Fig. 65. cup ; thence through the water to h, and from h along the wire I to o in the second cup ; thence in like manner through the water to h, and then along the wire i', and so on to N, the wire P being supposed to be connected with the positive pole of a battery, and the wire N with its negative pole. The current will therefore flow from P to N passing through the water in each of the cups. Under such circumstances the water will be gradually decomposed in each of the cups the particles of oxygen moving against the 5 THE ELECTRIC TELEGRAPH. course of the current, and those of hydrogen moving with it, the former are evolved at the points o, and the latter at the points h. 170. To show how this property of the current may be made to produce visible marks or signs, let us suppose a sheet of paper wetted with an acidulated solution of ferro-prussiate of potash to be laid upon a plate of metal, and let the point of a metallic style be applied to it so as to press it gently against the metallic plate without piercing it. Let the style be now put in metallic connection with the wire which leads to the positive pole of a voltaic battery, and let the metallic plate upon which the paper is laid be put in connection with the wire which leads to the negative pole. The current will, therefore, flow from the style through the moistened paper to the metallic plate, and it will decompose the prussiate, one of the constituents of which deposited on the paper will mark it with a bluish spot. If the paper be moved under the style while the current flows, this decomposition being continued under the point of the style a bluish line will be traced upon the paper. If while the paper is thus moved uniformly under the style, the current is permitted to flow only during intervals long or short, the paper will be marked by lines long or short, according to the intervals during which the current flows ; and, since no decomposition takes place during the suspension of the current, the paper then passes under the style without receiving any mark. If- the current be permitted to flow only for an instant, the paper will be marked by a dot. The long or short lines and dots, thus traced upon the paper, will be separated one from another by spaces more or less wide according to the lengths of the intervals of suspension of the current. It is evident that the same effects will be produced, whether the style be at rest and the paper moved under it as is here sup- posed, or the paper be at rest and the style moved over it. 171. The paper may be moved under the style by various and obvious mechanical expedients. Thus it may be coiled upon a cylinder or roller, which being kept in constant and uniform revolution by clock-work or other means, the paper would be carried continually under the style, and unrolled from the cylinder after receiving the marks. Or the cylinder covered with paper might, while it revolves, receive a slow motion in the direc- tion of its axis, so that the course of the style upon it would be that of the thread of a screw or helix. The paper might be cut into the form of a large circular disc, and laid upon a metallic disc of equal magnitude, to which a motion of revolution round its centre in its own plane might be imparted by clock-work ; while the style might receive a slow motion directed from the RELAY MAGNETS. centre of the disc towards its edge. In this case the style would trace a spiral curve upon the paper, winding round it continually, and at the same time retiring constantly hut slowly from its centre towards its edge. 172. Whichever method might be adopted, the paper would he marked with a continuous succession of comhinations of lines of varying lengths and dots, separated by spaces more or less wide. These marks depending altogether on the succession of intervals of suspension and transmission of the current, which intervals can be varied and combined at will by an operator supplied with the means of controlling the current which have been already ex- plained, it will be easily conceived that an agent at s can trace upon paper placed at s" in the manner here described such a succession of characters composed of lines and dots as he may desire ; and that an operator at s", being supplied with a key, may interpret these characters, and thus translate the communi- cation into ordinary language. It is also easy to conceive that the agent at s can stop'the clock- work which moves the paper at s" or set it going at will, in the same manner as he can ring a bell or discharge a cannon. 173. It has been already explained that the intensity of the current transmitted by a given voltaic battery along a wire of given thickness must decrease in the same proportion as the wire increases in length. -This loss of intensity due to the length of the wire is increased in the practical operation of the telegraphs by the loss of electricity arising from imperfect insu- lation and other inevitable causes. It has therefore become a matter of great practical importance to discover expedients by which the intensity of the current may be re-established, or by which the apparatus may be worked by a very feeble current. It was obvious that the intensity might be maintained at the necessary degree of force by providing, as already stated, relay batteries at intermediate stations sufficiently near each other to prevent the current from being unduly enfeebled. But the main- tenance of such numerous batteries in cases where great distances must be traversed is expensive, and it was desirable to discover some more economical expedient. 174. The properties of the electro-magnet have supplied the means of accomplishing this. The lever g h (fig. 58) may be constructed so light and so free, that it will be capable of being moved by a current of extremely feeble intensity. But if this lever were charged with any of the functions by which it would become an instrument for giving signals, such as the ringing of a bell or the motion of a style or pencil, it would be necessary to impart to the electro-magnet and THE ELECTRIC TELEGRAPH. its other appendages much greater power. So long, however, as no more is required than to make it oscillate between the stops t and tf, it may be constructed and mounted so as to be moved by the most feeble degree of magnetism imparted to m m' by a current of extremely low intensity. Now let us suppose the axis o of the lever g h to be in me- tallic connection with a voltaic battery placed near to it at the station s', and let the stop t' be in connection with the conducting wire which extends to another more distant station s". When the end g of the lever is brought into contact with the stop if, the current produced by the battery at s' will flow along the con- ducting wire to s" ; and when the lever deserts the stop V y and is thrown upon t, the contact being broken, the current is Now it is evident that by this means the original current flowing from the battery at the station s to the station s' is the means of calling into action another current, which flows from the relay battery at the station s' along the conducting wire to the station s", and that the intensity of this current will not be affected in any way by that of the original current from s to s', but will depend solely on the power of the relay battery at s', and the length of the conducting wire from s' to s". In the same manner another relay battery may be provided at s", and so on. In this succession of independent currents, those only which have signals to work need to have a greater intensity than that which is sufficient to give motion to a light lever, such as we have described above. It will be evident also by what has been stated that the pulsa- tions given to the original current at s, and the succession of intervals of transmission and suspension will be reproduced with the most absolute precision in all the succeeding currents, so that all signals which depend on these intervals of transmission and suspension will be made at the final station as promptly and exactly as if the original current from s to s' had been continued throughout the entire line of communication with all the neces- sary intensity. 175. The lines of electric telegraph which have been constructed and brought into operation in different parts of the world, like the lines of railway, have been established in some by private companies, and in others by the state. In the United Kingdom and its dependencies and in the United States they have been in all cases established by -the enterprise and capital of joint-stock 8 NATIONAL TELEGRAPHIC LINES. companies chartered or incorporated by the legislature, subject to certain conditions. On the continent of Europe generally they have been constructed and are exclusively worked by the state, but are placed under specified conditions and subject to regulated tariffs at the service of the public. 176. The forms of telegraphic instruments to which a preference has been given, in different countries are very various. In the United Kingdom and the United States, the several joint-stock companies by whom telegraphic lines have been constructed, have been generally formed by the friends and partisans of the inventors of particular telegraphic instruments, of which the companies have become severally the patentees. To these instruments they naturally have given a preference, in some cases irrespective of their merits, and as a necessary consequence every such company is more or less opposed, as well by interest as by prejudice, to other inventions and improvements. It has been a matter of complaint that such companies have sometimes become the purchasers of patented inventions for no other purpose than that of their suppression; and it is easily conceivable that a company having an extensive establishment in profitable operation may find it more advantageous to maintain their existing apparatus than to put them aside for others even of very superior efficiency. This is, after all, no more than what has occurred in the progress of all great inventions and improvements. 177. National feeling has, however , also had a considerable influence on the selection of the forms of telegraph adopted in different countries. T ! \us we find the telegraphs adopted in England exclusively English inventions ; those generally adopted in France, French inventions ; and those adopted in the United States, generally American inventions. 178. Amidst those conflicting motives directing the choice of companies and of governments, several inventions of great merit have necessarily been either wholly neglected, or bought up and wilfully suppressed, or in fine, brought into operation on a very limited scale. The vast resources supplied by the discoveries by which physical science has been enriched since the beginning of the present century, and the fertility of genius directed to the application of these resources in all countries, has produced a swarm of inven- tions, even the least efficient of which possess great merits on the score of ingenuity and address in the application of physical principles. Our limits, the purposes to which this series is. directed, and the large and various classes to which it is- addressed, compel us to pass without notice many forms of telegraph which have been contrived and constructed. We shall 9 THE ELECTRIC TELEGRAPH. therefore confine our observations to those apparatus which have been actually employed on the telegraphic lines established in different countries, and a very few others which appear to claim more especial attention. On the claims of various projectors on the score of original invention, we must generally decline to enter. To discuss such questions so fully as to render justice to the claimants would require much more space than we can devote to the subject ; and however interesting such a discussion might be to the inventors themselves and their partisans, it would offer but few attractions to the masses to whom our " Museum" is addressed. We shall therefore first explain briefly the forms of telegraph generally applied in this country, and next those which are in operation elsewhere. 179. The telegraphic instruments used almost exclusively in this country are galvanometers (138), which make their signals by means of the deflections of magnetic needles, produced by the electric current. These instruments are of 'two forms, the first, and most simple, consisting of one needle with its appendages and accessories, and the other of two independent needles, each accompanied by its own appendages. THE SINGLE NEEDLE INSTKUMENT. 180. This instrument consists of a galvanometer and a commu- tator, mounted in a case resembling in form and size that of an ordinary table time-piece. A front view of it is given in fig. 66 (vol. iii. p. 161). On the upper part is a dial, in the centre of which the indicating needle appears, like the hand of a clock, fixed upon an axis. Its plaj r to the right and left is limited by two ivory studs inserted in the face of the dial, a short distance on each side of its upper arm. The handle which works the commutator, also fixed upon an axis, is presented at the lower part of the case, under the dial. Upon the dial are engraved the letters of the alphabet, the ten numerals, and one or two arbitrary symbols, under each of which is engraved a mark, indicating the motions of the needle, by which the letter or figure is expressed. The galvanometer, constructed as already explained (140), is attached to the back of the dial, the axis of its magnetic needle passing through the dial and carrying the indicating needle in front. The latter is also usually magnetic, its poles being reversed in their direction with relation to those of the interior needle, the 10 SINGLE NEEDLE TELEGRAPH. effect of which is, that the current transmitted through the gal- vanometer has a tendency to deflect both needles in the same direction. The indicating needle, however, need not be magnetic. If it be sufficiently light, being free from magnetism, it will be carried by the axis to the right or left against the studs, by the deflections of the galvanometric needle which plays within the i coils of the galvanometer, -to 'which it is always parallel. In connection with the instrument there are, as usual, an alarum and a galvanic battery. By the commutator, the current produced by the* battery may be transmitted upon the line- wire, or suspended or reversed in its direction, according to the position given to the handle. If the handle be vertical, as represented in the figure, the current is sus- pended, the arrangement of the commutator being then such as to cut off all communication between the battery and the line- wire. If the upper arm of the handle be turned to the right, the battery will be connected with the line-wire, on which accordingly the current will be transmitted. If the upper arm be turned to the left, the battery will still be connected with the line-wire, but with its poles reversed, so that the direction of the current on the line-wire will be reversed. The mechanical form of the commutator, by which these changes of connection are made is different from that explained in (111), but the principle is the same, and the variation of the details are unimportant. To comprehend the practical operation of the instrument, we are to consider that similar instruments, with similar accessories, are placed at each of the stations, between which dispatches are to be transmitted. To render the explanation more clear, let s and s', fig. 67, be the two stations, o and o' the dials, c and c' the handles of the commutators, and B and B' the galvanic batteries. If it be intended to send a dispatch from s' to s, the arm of the commutator, c, is left in its vertical position, so that no current can pass from the battery, B, to the line-wire, L. 11 THE ELECTRIC TELEGRAPH. When the arm of c' is vertical, no current can pass from B' to L r and consequently the needle of o will remain in the vertical direction, without deflection. If the upper arm of c' be turned to the right, r, the current from B', passing along L, will flow through the coil of the galvanometer at s, and will deflect the indicating needle to the right, so that it will lean upon the right hand stud, R. If c' be then turned back to the vertical direction, the current will be suspended, and the needle at s will return to the point o. If the upper arm of c' be then turned to the left, 7, the current will be again transmitted upon the line-wire, L, but in a direction contrary to its former course, and thus passing through the gal- vanometer at s, in a contrary direction, the needle, which was before deflected to the right hand stud, E, will now be deflected to the left hand stud, L. Thus, it appears, that according as the upper arm of c' is turned to the right or left, or placed in the vertical position, the needle on the dial at s, is also turned to the right or left, or placed in the vertical position. In a word, whatever position is given to the handle of the com- mutator at s', a corresponding position is assumed by the indicat- ing needle at s, and these changes of position of the indicating needle at s, are absolutely simultaneous with the changes of position of the handle of the commutator at s'. The manner of expressing the letters and figures, is by making repeated deflections of the needle right and left, making a short pause at the end of each letter signal. Thus two deflections to the left express A ; three, B ; four, c ; while one expresses the completion of a word. One to the right expresses M ; two, BT ; three, o ; and four, p. In the same manner, L is expressed by four deflections, which are, successively, right, left, right, and left. As these signs are purely arbitrary, and may be changed in every independent telegraph, it is not necessary here to notice them further. Besides the signals which express letters and figures, it is usual to adopt others to express words or phrases of very frequent occurrence, such as, I don't understand, I understand, wait, go- on, repeat, &c. It is usual, though not necessary, for the agent who sends a dispatch, to pass the current through his own instrument, so that his indicating needle shows exactly the same deflections as the indicating needle of the station he addresses. Thus, when s' addresses s, his own indicating needle, o', speaks as well as the- indicator, o, of the station, s. All that has been stated in (111) et seq. of the transmission of the same despatch through a series of stations, of cutting off the 12 DOUBLE NEEDLE TELEGRAPH. transmission from all stations except that to which it is exclusively addressed, of the use of the alarum, &c., is applicable, without any important modification to this form of telegraphic instrument. THE DOUBLE NEEDLE TELEGRAPH. 181. This is nothing more than two single needle telegraphs, such as has been just explained, mounted in the same case, their indicating needles playing side by side upon the same dial, and the handles of their commutators placed so that they can be con- veniently worked at the same time, by the right and left hand of the telegraphic agent. Each instrument is altogether inde- pendent of the other, having separate accessories, and transmit- ting its current upon a separate line-wire. The purpose of this form of instrument is merely to accelerate the transmission of dispatches, by enabling the agent to produce the signals expressing letters and figures in more rapid succes- sion. In the single instrument there are only two signs made by one deflection of the needles, viz., a deflection to the right and one to the left. In the double instrument there are eight such signs, viz., two with each needle, as in the single instrument, and four obtained by combining the deflections of the two needles. Thus, if o express the position of the needle without deflection, r, a right hand, and / a left hand- deflection, and K the right hand, and L the left hand needle, the following eight signals may be made in the time of a single motion of either needle. With a single needle two deflections can only make four signals, viz., rr, II, rj, Ir. But with two needles, these being combined 13 THE ELECTRIC TELEGRAPH. with single deflections and with each other, a greater number of different signals can be obtained than are sufficient to express the letters and numerals, each being made in the time necessary for two deflections of a single needle. A front view of a double needle telegraph is given in fig. 68 (vol. iii. p. 177). The small case at the top contains the alarum, and the small handle at the side of the large case is the commutator by which the current is turned on and off the alarum. The two large handles which appear in front are those of the commutators, which produce the changes of direction of the current, and when inclined to the right or left the needles acted on by the current assume a like position. FEEXCH STATE TELEGEAPH. 182. When T the establishment of lines of electric telegraphs was proposed in France, the old aerial telegraph was, and had been for more than half a century, in operation, and formed a depart- ment in the public administration of considerable importance, employing an extensive body of agents, dispersed throughout the country, most of whom were specially instructed and qualified for the business. The commission appointed by the government required that the electro-telegraphic instruments should exhibit the same signals as had been already used in the case of the former telegraph. The old telegraph consisted of a long straight bar, E E', fig. 69, called a regulator, to the extremities of which two shorter bars, r r', called indicators, were attached by pins or pivots, so that each indicator was capable of turning on its pivot, so as to make any desired angle with the regulator. Fig. 69. "X / "' IT'' i P If we suppose the circle described by each indicator to be divided into eight equal arcs of 45, and that any convenient mechanism is provided, by which the agent who conveys the signals can at will give to each indicator any of these eight positions, each indi- cator would be capable of making eight signals, and by combining these in pairs, the two indicators worked together would be capable of giving sixty-four signals. It is evident that even this large number of signals might be 14 FRENCH STATE TELEGRAPH. further multiplied, by giving to the regulator itself a motion round its centre, so that it might at will assume the horizontal or vertical position, or might take an intermediate direction. In transferring this system of signals to the electric telegraph, the regulator is supposed to he placed permanently horizontal, and the two indicators to be capable of receiving any of the eight positions here explained. 183. The telegraph contrived by M. Breguet, to exhibit such a system of signals, consists, like the double needle telegraph, of two distinct and perfectly similar instruments, one for each of the indicators. They are mounted side by side with their accessories in the same case, at a distance apart sufficient to allow the indi- cators to revolve without mutual obstruction, and sufficiently near each other to allow the same person to work both at the same time with his right and left hand. Each instrument consists of an indicating apparatus and a com- mutator. If s and s' be two stations, between which dispatches are trans- mitted, the commutator at s moves the indicator at s 7 , and the commutator at s' moves the indicator at s. A view of the indicating apparatus is given in fig. 70. The two indicators are fixed upon axes placed in the same horizontal Fig. 70. line upon the dial. These axes, passing , through the dial, carry behind it two escapement wheels, which are controlled by two anchors, as described in 151. These anchors are moved by the armatures of two electro-magnets, from which they receive vibra- tions, like those of a pendulum. The escapement wheels are impelled by the force of two main-springs, transmitted to them by two similar trains of clock-work. 15 THE ELECTRIC TELEGRAPH. Thus, for each swing of the anchor, the indicator makes one motion forward, and as the escapement wheels have each only four teeth at equal distances, one complete revolution of these wheels must cause the indicators to make a complete revolution by eight distinct motions, produced by the four swings of the anchor to the right, and the four swings to the left. During a revolution of each of the escapement wheels, therefore, each of the indicators takes successively the eight positions required in the proposed system of signals, and since the motions of the indicators are governed by the anchors, those of the anchors by the armatures of the electro-magnets (154), and those of the electro-magnets by the successive pulsations of the electric current, it follows that if it can be contrived that commutators at one of the stations shall govern the pulsations of the current at the other, they will necessarily govern the motion of the indicators at that other station. At the upper corners, right and left of the front of the case, are two dials, in the centre of which are axes, which act, when turned, upon the springs which draw back the armatures of the two electro-magnets, and near them keys for their adjustment are sus- pended by chains. The springs are raised or relaxed, according as the keys are turned in the one direction or the other. Under the indicating arms are two axes with square ends, by which the two systems of clock-work can be wound up, which is done by the same keys. 16 Fig. 74. FRENCH RAILWAY TELEGRAPH. THE ELECTRIC TELEGRAPH. CHAPTER VIII. 1S4. Form of commutator of French state telegraph. 185. Its operation. 186. Method of sending and receiving a despatch. 187. Batteries. 188. French railway telegraph. 189. French railway portable tele- graph. 190. German railway telegraph. 191. Siemens' instrument. LARDNER'S MUSEUM, OF SCIENCE. c 17 No. 42. THE ELECTEIC TELEGRAPH. Fig. 71. 192. Its mode of operation. 193. How errors are corrected. 194. Explanation of the mechanism. 195. Comparison with the French telegraph. 196. Indicating mechanism. 197. Simplicity greater than the French instrument. 198. Requires greater intensity of current. 199. Belgian railway telegraph. 200. Defects imputed to the French and German instrument. 184. IT remains, therefore, to show the manner in which, the pulsations of the current are governed by the commutator. One of the commutators is represented in fig. 71. The handle M is fixed upon an axis which turns in the centre of a fixed disc D, the edge of which is divided into eight equal parts by small notches. A short pin projects from the handle which falls successively into these notches, but which can be with- drawn from them when it is re- quired to turn it. On the remote end of this axis a disc is fixed, which turns with it, in the face of which a square groove is cut, rounded at the corners, in which a pin projecting from a short lever I is moved. This lever I is fixed on the axis c c, upon the other end of which is fixed the lever L, the lower end of which carries a small piece of metal r, which, when the lever vibrates right and left, is thrown alter- nately against the contact-pieces x and x'. Supposing that the commutator is placed at the station s, the line-wire which comes from the station s' enters the foot, and is held there by a tightening screw A. This wire is in metallic con- nection, through the pillar, with the lever L, and consequently with the piece of metal at its lower end, which oscillates between the contact-pieces x and x'. This piece of metal, r, may therefore be considered as virtually the extremity of the conducting wire between the stations s and s'. Attached in like manner, by tightening-screws, to the two contact-pieces K and x' are two wires, one of which is connected with the battery, and the other with one end of the coil- wire of the electro-magnet, in the indicating instrument of the station s. 18 FEENCH STATE TELEGRAPH. The other end of this coil-wire is either connected with the line- wire which proceeds to the succeeding station, or with the earth, at the option of the agent, a commutator being provided by which this change of direction may be made. 185. Let us see, then, in what manner the agent at s, provided with such a commutator, can govern the motion of an indicator at s'. The arrangement of the apparatus is such, that when the handle M of the commutator is presented vertically upwards, as represented in the figure, the pin being in the highest notch, the lever L presses against the contact-piece K. Let the highest notch be supposed to be numbered 1, and the others proceeding round the disc, in the direction of the motion of the hand of a clock, be numbered successively 2, 3, 4, 5, 6, 7, and 8, It must be remembered, that at the other station, s', there is another commutator precisely similar, the corresponding points of which we shall express by the letters M', D', n', &c. Let us see, then, how the agent at s, by moving round the handle M from notch to notch, can govern the motion of the indi- cator at s'. The commutator and indicator at the station s', when not employed in the transmission of a despatch, are placed respectively with the arm M', having its pin in the notch 1', and the hand of the indicator directed vertically upwards. 186. The arm M being, as represented in the figure, in the notch 1, let it be moved to the notch 2. The lever L being moved to the right, the piece r will be thrown upon K'. Being then in connection with the battery- wire, the current will pass by r and L to A, and thence by the line-wire to the corresponding point A' of the commutator at the station s', and thence through the pillar to the lever I/ and the piece r'. But since, as has been just explained, M' is in the notch 1', the piece r' must rest against K. The current, therefore, arriving at this point, will pass from- K by the wire to the coil of the electro-magnet at s', to which it will impart magnetism, so that it will attract the armature, and move the anchor of the escapement, so as to make the indicator move from the vertical position 45 in the direction of the hand of a clock. If the handle M be now moved from notch 2 to notch 3, the lever L will be thrown back to K, and the contact with K' being broken, the current will be suspended, and the electro-magnet at s' losing its power, the armature will recoil from it by the action of the spring (147) and the anchor of the escapement being again moved, the indicator will be advanced through another angle of 45, and will be then in the horizontal position pointing to the right. c2 19 THE ELECTRIC TELEGRAPH. In like manner, it may be shown that when the arm M is moved from the notch 3 to the notch 4, the indicator at a' will be moved from the horizontal position to one which will make an angle of 135, with its original direction, or what is the same, 45, with the position in which it would point directly downwards. Without pursuing this explanation further, it will be easy to see that the successive positions assumed by the hand of the indicator at s' correspond with those given to the arm M of the commutator at s. We have here explained the action of one commutator at s upon one indicator at s'. The action of the other commutator at s upon the other indicator at s' is precisely the same. It must be under- stood, that the two commutators at s are connected with separate and independent line-wires, are supplied with separate and inde- pendent batteries, and act upon separate and independent indicators at s'. The right-hand commutator at s is connected with the right-hand indicator at s', and the left-hand commutator with the left-hand indicator. From what has been explained, the process necessary, as well for receiving as for transmitting a despatch will be understood. In the reception of a despatch, the agent has only to place the handle of his commutator in notch 1, and to see that his indicator is vertical. After that he has only to observe the successive attitudes assumed by the two indicators upon the dial before him, and to write down the letters they successively express. Since this form of telegraph gives 64 signs, while 26 are suffi- cient for the alphabet, and 10 for the numerals, there are 24 signs disposable for abridgements, such as syllables, words, and phrases of most frequent occurrence. 187. The battery employed in working these telegraphs is at present invariably that of Daniel (32). Formerly Bunsen's battery (34) was used at chief stations, where great power is often required, but this has now been discontinued. Between the point K' and the battery a commutator is placed, by >ieans of which the agent can bring into action a greater or less number of the pairs composing the battery, so as to proportion the power to the distance to which the current is to be transmitted, or to the resistance it may have to overcome. A perspective view of the telegraphic instrument, showing the two indicators and two commutators, in their respective positions, is given in fig. 72 (vol. iii. p. 193). FRENCH RAILWAY TELEGRAPH. 188. The telegraphs which convey letters or words by conven- tional signals, like those described above, require a staff of agents 20 FRENCH RAILWAY TELEGRAPH. engaged in their management, who have been specially instructed and practised, as well in working the instruments as in interpreting their signs. That this is deemed a matter of great practical importance in telegraphic economy is manifested by the fact already mentioned, that the French government, before it resolved to establish the electric telegraph, caused instruments, on the new principle, to be constructed, by which the same system of symbols could be used as that which had been previously adopted in the semaphore. Nevertheless, in cases like that of a system of telegraphs in which not only the business of the state, but that of the public, is to be transacted, and where, therefore, a permanent staff is employed exclusively in the management of the apparatus, no very serious difficulty can be encountered, even if the necessity of having a new telegraphic vocabulary is imposed upon these agents. For a short time the service will be slow, and less satisfactory, but the inconvenience is temporary, and constant practice in the manipulation of the apparatus, and in the interpretation of the signs, whatever they may be, renders the agents sufficiently expert. The case is different with telegraphs used, not for state or com- mercial purposes, but exclusively for railway business. The telegraphs even of principal railway stations, and still less those of secondary stations, are not in that constant requisition, and consequently do not occupy a permanent and exclusive class of agents. They are managed by any persons who happen to be employed in the respective offices : by the station-masters, clerks, railway police, guards, or, in short, by any railway agent who may happen to be at hand. Now it is evident that telegraphic instruments, the use of which would require special instructions, and much previous practice, would not answer such a purpose. These considerations have prevailed, with the administrations of the lines of railway in all parts of the continent, and have led them to adopt telegraphic instruments which satisfy the conditions explained above, more completely than do the apparatus which have been adopted for state and public communications. In general the railway telegraphs are of the class called " letter or alphabetic telegraphs." The agent who transmits a message is supplied with a hand which moves upon a dial, round which the letters of the alphabet are engraved, as are the hours round the dial of a clock. At the station to which the message is sent, there is a similar dial, having upon it a similar hand, and the mechanism is so contrived that, when properly adjusted, the two hands must always point to the same letter. Thus, if the agent sending the message turns the hand to the letter JE upon the dial before him, 21 THE ELECTRIC TELEGRAPH. the hand upon the dial at the station to which the message is sent will also turn to the letter M, and in this way, by merely directing* the hand successively to the letters of a word, pausing a little while at each letter the word will be spelled to the agent at the distant station. All alphabetic telegraphs, whatever be their form or construc- tion, convey the communications in this manner. The French railway telegraph is in its principle identical with the state telegraph. The indicator in the latter makes a complete revolution by eight successive steps, moving in each step through an angle of 45. If the alphabet consisted of only eight letters, this would at once become an alphabetic telegraph by fixing the indicator in the centre of a dial upon which, at equal distances asunder, the eight letters are engraved. But since the French alphabet consists of 25 letters, and since an additional sign is found convenient, the dial is divided into 26 equal arcs instead of eight, and the indicator makes a complete revolution by 26 equal motions, at the termination of these motions respectively pointing to the letters engraved upon the dial. To accomplish this, the escapement wheel is constructed with 13 teeth instead of 4, the groove upon the moveable disc of the commutator has 13 sinuous undulations instead of 4 sides with rounded corners, and the fixed disc upon which the handle of the commutator moves, has 26 notches instead of 8. The grooved disc, by the motion of which the oscillations right and left are imparted to the lever which makes and breaks the connection with the battery, is fixed immediately behind the notched disc, and the sinuous groove has the form represented in fig. 51, and acts upon the lever in the manner described in 133. The commutator, with its appendages, is represented in fig. 73. The fixed disc has at its edge 26 notches, into which the pin projecting from the handle falls, as in the state telegraph. Engraved upon the face of the disc are, on the outside, the numbers from to 25, and on the inside the 25 letters (W being omitted, not being generally used in the French language), the 26th place having the mark -j- A part of the dial is broken away, to disclose the face of the moveable disc, with the sinuous groove behind the fixed disc. The lever G is visible, with its pin in the groove, and the oscilla- tion of the end of the lower arm H between the contact-pieces,, p and P', is exactly the same as that described in 133 and in 184. The handle of the commutator is keyed upon an axis which, passing through the centre of the fixed dial, is itself keyed into- the centre of the moveable grooved dial behind it, so that when. 22 TRENCH RAILWAY TELEGRAPH. the handle is carried round the fixed dial, the moveable dial behind is carried round with it. Upon the upper part of the board carrying the dial are placed two supplementary commutators, L and I/, the hands of which play upon the contact-pieces, s, s, E, and s', s', E', as well as upon an oblong plate of metal, upon which the words " COMMUNICATION DZRECTE " are engraved. The terminals c and z communicate with the copper and zinc ends of the battery, or what is the same, with its positive and S s E negative poles ; T communicates with the earth. The contact pieces s s' are connected with alarums, n it with the indicators, and the axes of the arms L I/ with the line-wires. The dotted lines indicate the positions of slips of metal inlaid in the back of the frame, by which the several pieces are put in metallic connection one with another. After the general explanation of the manner in which the course of the current is in all cases governed, it will not be necessary here to explain the application of these commutating apparatus, which are nothing more than particular applications of the general principle so fully developed in 111. A perspective view of the commutator and indicating apparatus mounted in the same case, is given in fig. 74 (p. 17). The com- mutator is fixed upon a horizontal desk, that being the most convenient position for its easy and rapid manipulation. The 23 THE ELECTRIC TELEGRAPH. indicator, which corresponds with it in form, is placed like the dial of a clock in front of a vertical case. If we suppose the commutator (fig. 73) at the station s, and the indicator at s', the arm of the commutator and that of the indi- cator being upon the mark +> an y motion of tfye former made in the direction of the hand of a clock, will produce a corresponding motion of the hand of the latter, so that whatever letter or number the one points to, the other will at the same time point to. By this means the agent at s may spell word after word to the agent at s'. There are various conventional signs, made by two or more complete turns of the handle of the commutator, which, being altogether arbitrary, and matters of local convenience, need not be noticed here. It is found that moderately well-practised hands can transmit with this instrument forty letters per minute, while the most expert can send as many as sixty. A side view of the wheel-work and electro-magnet, E, of the indicating apparatus is given in fig. 75. The armature, P, is alternately attracted and dismissed by the Fig. 75. magnet, acted on by the pulsations of the current, and imparts this motion to the escapement at F, by which the hand A of the indicator is advanced from letter to letter upon the dial, so that the motion of the hand A at the station s' shall correspond exactly with that of the hand of the commutator at the station s. 24 FKENCH EAILWAY TELEGRAPH. 189. The telegraph which is represented in fig. 74 is a portable telegraph constructed for the French railways by M. Breguet. This instrument, in size and arrangement, is adapted to be carried in the guard's van upon the train, so that, in case of accident, it may be immediately put in connection with the line-wires, and notice of the circumstance may be instantly transmitted to the two stations between which the accident has taken place. Portable instruments for a like purpose have been constructed in England and elsewhere. The apparatus consists of a stout oaken case, containing in the lower part, B B, a Daniel's battery of 18 pairs, a commutator, M, and an indicating apparatus, E. A small galvanometer is placed at G, to show the existence and force of the current, and a small electro-jnagnet, L T. The dimensions of the instrument are indicated on the figure. "When not in use the top, c c, attached by hinges to the case, can be turned down over the commutator and indicator, so as to close the entire apparatus. A long rod of metal terminated in a copper hook, is provided, by which the end of the coil L can be put in connection with the line-wire ; the end of the coil T being put in connection with the earth by means of a wire terminating in a small iron wedge, which is driven with a hammer into the joint between two of the rails. .To explain the manner of applying this apparatus, let us suppose an accident to happen between the stations s and s', and consequently the train to be stopped. The guard takes out the portable telegraph, and raising its cover c c, he puts the wire of L in connection with the line-wire, and that of T within a joint of the rails, in the manner described above. He then makes one or two complete turns of the handle M of his commutator, observing whether the galvanometric needle G is deflected. If it is, he knows that he has transmitted a current to the line wires. This current divides itself at the hook, and a part goes to each of the stations s and s', at each of which it rings the alarum. After a short interval a current is transmitted back from one or other of the stations, the arrival of which is indicated by the deflection of the galvanometric needle, G. The guard then informs the stations, one or both, of the accident, its place, the nature of the aid he requires, &c. In comparing this with the state telegraph, it must not be forgotten that while this requires only one conducting wire, the state telegraph requires two. In fact, the French state telegraph, like the English double-needle telegraph, is in reality two inde- pendent telegraphs, whose signals are combined for the purpose of 25 THE ELECTRIC TELEGRAPH. indicating hands, n, in all of them were placed upon the division of the dial marked -f . The moment the arms, a b, or any of them, are placed against the stops T, the current transmitted upon the line -wire passing through the several indicating instruments, the indicating hands in all the instruments will commence simul- taneously to move round the several dials. They will move from letter to letter with a starting and interrupted, but regular motion, like that of the seconds hands of a clock, but much more rapidly. The rate at which they are moved will depend on the force of the current, but, whatever be the rate, it will be common to all, all making successive revolutions of the dial precisely in the same time, and moving together from letter to letter with the most absolute simultaneity, and since they all started from the same point 4-j and move together from letter to letter, it follows that, whether their motion be quick or slow, they will all at each moment point to the same letter. Now, it is important here to observe, that this common rotation of all the hands upon all the dials is produced and maintained by the current alone, without any manipulation whatever on the part of any agent at any station, and it would continue to be main- tained indefinitely, provided that the battery were kept in action. We have supposed the battery at the station s, from which the despatch is about to be transmitted, to be alone put into connection with the line-wire. But, in order to strengthen the current, each agent on the line, when he receives the signal, also puts his battery in like connection with the line-wire, so that the current acquires all the intensity which the combined action of all the batteries on the line is capable of producing. The apparatus is so arranged that, in all cases, the galvano- meter, d, is in connection with the line-wire, so as to indicate at all times at each station the state of the current. It now remains to show how a despatch can be transmitted from any one station to all or any of the other stations on the line. The apparatus is so constructed, that if the agent at any station presses down any one of the keys surrounding the dial, the indicating needle, upon arriving at that key, will be stopped ; and at the same moment the current upon the line-wire will be suspended. This suspension of the current will also, at the same moment, stop the motion of all the indicating hands upon all the dials on the line. The agents at all the stations will therefore see and note the letter on which the transmitting agent has put his finger. The transmitting agent, after a sufficient pause, transfers his finger to the key of the next letter he desires to transmit. The moment he raises his finger from the first key the current is re-established on the line-wire, and all the indicating 28 GERMAN RAILWAY TELEGRAPH. hands rotate as before, passing again simultaneously from letter to letter until they arrive at the second letter upon which the transmitting agent has put his finger, when they again stop, and so on. In this manner an agent at any station can stop the indicating -needles at any or all the other stations successively, on their arrival at the letters of the words he desires to communicate. 193. If by reason of inattention or otherwise any letter or letters transmitted escape the attention of the agent at any of the stations to which the despatch is addressed, such agent immediately signifies the fact by putting his finger on one of the keys of his own instru- ment, by which he stops the hand upon the dial of the transmitting agent at a letter, which tells him to repeat the last letter or word as the case may be. This signal is understood at all the other stations, so that no confusion ensues. 194. Having thus shown how a despatch is transmitted and understood by those to whom it is addressed, I shall now explain the mechanism by which these effects are produced. Beneath the dial of each instrument an electro-magnet, such as m m' (fig. 77) is placed, upon, the coil of which the current trans- mitted from the batteries passes. This magnet, then, as usual, attracts its armature g o, which comes against the stop if Now the apparatus is so arranged, that when g strikes f, the circuit of the current is broken, and consequently the current is stopped. This deprives the electro- magnet m m' of its magnetism ; and g being no longer attracted, it is drawn back from the stop if by the spring s, and it recoils upon the stop t. Here the connection with the line-wire is repro- duced, and the current is re -established. The electro-magnet having thus reco- vered its magnetism, g is again attracted by it, and drawn into contact with t' } where the connexion is again broken, and g is drawn back to V by the spring , *, and so on. Since the intervals of transmission and suspension of the current are the same throughout the entire line, and since the intervals of transmission are those in which the armature moves towards the electro-magnet, and the intervals of suspension those in which it recoils from the magnet, it follows that the oscillations of the armature of all the electro-magnets at all the stations are absolutely alike and simultaneous. 29 THE ELECTRIC TELEGRAPH. indicating hands, w, in all of them were placed upon the division of the dial marked + . The moment the arms, a b, or any of them, are placed against the stops T, the current transmitted upon the line -wire passing through the several indicating instruments, the indicating hands in all the instruments will commence simul- taneously to move round the several dials. They will move from letter to letter with a starting and interrupted, but regular motion, like that of the seconds hands of a clock, but much more rapidly. The rate at which they are moved will depend on the force of the current, but, whatever be the rate, it will be common to all, all making successive revolutions of the dial precisely in the same time, and moving together from letter to letter with the most absolute simultaneity, and since they all started from the same point + , and move together from letter to letter, it follows that, whether their motion be quick or slow, they will all at each moment point to the same letter. Now, it is important here to observe, that this common rotation of all the hands upon all the dials is produced and maintained by the current alone, without any manipulation whatever on the part of any agent at any station, and it would continue to be main- tained indefinitely, provided that the battery were kept in action. We have supposed the battery at the station s, from which the despatch is about to be transmitted, to be alone put into connection with the line-wire. But, in order to strengthen the current, each agent on the line, when he receives the signal, also puts his battery in like connection with the line-wire, so that the current acquires all the intensity which the combined action of all the batteries on the line is capable of producing. The apparatus is so arranged that, in all cases, the galvano- meter, d, is in connection with the line-wire, so as to indicate at all times at each station the state of the current. It now remains to show how a despatch can be transmitted from any one station to all or any of the other stations on the line. The apparatus is so constructed, that if the agent at any station presses down any one of the keys surrounding the dial, the indicating needle, upon arriving at that key, will be stopped ; and at the same moment the current upon the line-wire will be suspended. This suspension of the current will also, at the same moment, stop the motion of all the indicating hands upon all the dials on the line. The agents at all the stations will therefore see and note the letter on which the transmitting agent has put his finger. The transmitting agent, after a sufficient pause, transfers his finger to the key of the next letter he desires to transmit. The moment he raises his finger from the first key the current is re-established on the line-wire, and all the indicating 23 GERMAN RAILWAY TELEGRAPH. hands rotate as before, passing again simultaneously from letter to letter until they arrive at the second letter upon which the transmitting agent has put his finger, when they again stop, and so on. In this manner an agent at any station can stop the indicating needles at any or all the other stations successively, on their arrival at the letters of the words he desires to communicate. 193. If by reason of inattention or otherwise any letter or letters transmitted escape the attention of the agent at any of the stations to which the despatch is addressed, such agent immediately signifies the fact by putting his finger on one of the keys of his own instru- ment, by which he stops the hand upon the dial of the transmitting agent at a letter, which tells him to repeat the last letter or word as the case may be. This signal is understood at all the other stations, so that no confusion ensues. 194. Having thus shown how a despatch is transmitted and understood by those to whom it is addressed, I shall now explain the mechanism by which these effects are produced. Beneath the dial of each instrument an electro-magnet, such as m m' (fig. 77) is placed, upon, the coil of which the current trans- mitted from the batteries passes. . This magnet, then, as usual, attracts its armature g o, which comes against the stop f , Now the apparatus is so arranged, that when g strikes if , the circuit of the current is broken, and consequently the current is stopped. This deprives the electro- magnet m m' of its magnetism ; and g being no longer attracted, it is drawn back from the stop if by the spring s, and it recoils upon the stop t. Here the connection with the line-wire is repro- duced, and the current is re -established. The electro-magnet having thus reco- vered its magnetism, g is again attracted by it, and drawn into contact with t', where the connexion is again broken, and g is drawn back to t' by the spring s, and so on. Since the intervals of transmission and suspension of the current are the same throughout the entire line, and since the intervals of transmission are those in which the armature moves towards the electro-magnet, and the intervals of suspension those in which it recoils from the magnet, it follows that the oscillations of the armature of all the electro-magnets at all the stations are absolutely alike and simultaneous. 29 Fig. 77. THE ELECTRIC TELEGRAPH. In each instrument the armature is in connection with a toothed wheel, upon the axis of which the hand m n (fig. 76) is keyed, so that each vibration of the armature puts forward one tooth of the wheel, and advances the hand n from one letter to another. 195. Upon comparing this arrangement with that of the French telegraph, it will be perceived that here the mainspring and wheel- work which moves the indicator are altogether omitted, and the armature of the electro-magnet, which in the French instrument only regulates the motion of the indicator, here both moves and regulates it. In fine, the armature here discharges at once the functions of the mainspring, and of the pendulum of a clock. It will also be observed that the manipulation of the transmitting agent, by which he moves the indicators on the dials of the distant stations, is dispensed with, the current itself, through the inter- vention of the armature of the electro-magnet, imparting to the indicator a constant motion of rotation without any manipulation -whatever. That part only of the manipulation by which the indicator is stopped for a moment successively at the letters of the word intended to be transmitted, is retained, and tjiat is effected by the action of the keys surrounding the dial. 196. Under the dial, a radius or arm is keyed upon the axis on which the indicating hand is fixed, so as to be always immediately under that hand and parallel to it, revolving simultaneously with it. This radius is a little longer than the indicating hand, and extends under the keys surrounding the dial. From the under-surface of each key a pin projects, the length of which is such that when the key is not pressed down, the radius passes freely under it ; but when the key is pressed down, the pin comes in the way of the radius, and stops it when the indicating hand n arrives at the letter engraved on the key. By the action of the same pin the armature o g (fig. 77) of the electro-magnet is arrested in its return from V to t, so as to be prevented from arriving at t. The current, therefore, is prevented from being re-established on the line-wire, as it would be if g o were permitted to come into contact with t . Thus it will be understood how by putting down a key the two desired effects are produced. 1st, the stoppage of the indicating needles at the letter engraved on the key of the indicator on which such key is put down ; and 2nd, the simultaneous suspension of the current along the entire telegraphic line, by which the indi- cating needles of all other instruments are stopped at the same letter. 197. This apparatus, compared with the French telegraph, to which it has an obvious analogy, has the advantage of greater simplicity. By dispensing with the mainspring and its necessary 30 BELGIAN RAILWAY .TELEGRAPH. train of wheel-work, and with the rather complicated commutator worked by the hand of the transmitting agent, many moving parts are rejected, and there are proportionately less chances of derange- ment and less causes of wear or fracture. But on the other hand the moving power which impels the indicator, being transferred from the mainspring to the current, a proportionately greater force of current is necessary. This force is, however, obtained without augmenting the magnitude of the batteries at any one station by the expedient of bringing the piles of both the terminal stations, and, if necessary, of any or all the intermediate stations, into the circuit. 198. In the batteries used with the French railway telegraph, the use of acid, as has been stated, is found altogether unneces- sary. In the German telegraph, however, pure water does not give a sufficiently strong current, and it is acidulated with about one and a half per cent, of sulphuric acid. The battery at each station consists usually of from 15 to 20 pairs. The usual speed imparted to the indicator by the current is about 30 revolutions per minute. M. Siemens invented mechanism by which the indicating apparatus was connected with one by which the letters of the despatch as they arrived were printed by ordinary type upon a band of paper. Since, however, this has not been brought into practical use, it will not be necessary to explain it. When the electric telegraph was first opened to the general service of the public in Prussia, this apparatus of Siemens was generally used, but it has since been superseded by that of Morse, its speed of transmission being found insufficient for the public service. BELGIAN HALLWAY TELEGBAPH. 199. When the electric telegraph was first brought into use on the Belgian railways, the French and German apparatus described above were tried in succession. In 1851 they were, however, both superseded by a form of telegraph invented and constructed by M. Lippens, mathematical instrument maker of Brussels. 200. M. Lippens attributes to the French and German railway telegraphs certain defects, which he claims to have removed. For the efficient performance of those telegraphs, it is evident that a certain relation must always be maintained between the force of the spring s (fig. 77), which produces the recoil of the armature g o, and the attractive force of the magnet, or what is the same, between the spring and the intensity of the current, with which the attrac- tion of the magnet must vary. Now the intensity of the current is subject to variation, depending on the state of the battery, the number of pairs which are brought into operation, the length of 31 THE ELECTRIC TELEGRAPH. the line -wire upon which it is transmitted, the more or less perfect state of the insulators, and in fine on the weather. If the current become so feeble that the attraction of the magnet is less than the force of the spring s, the armature g o will remain upon the stop t, from which the magnet is too feeble to remove it. If, on the other hand, the spring have not sufficient force to overcome the friction and inertia of the armature g o, and the small portion of magnetism which may be retained by the electro-magnet after the current has been suspended, the armature will remain upon the stop ', the spring being unable to produce its recoil. Since therefore the forces against which the spring s acts, and which it ought to exceed, and those which act against it and which ought to exceed it, are variable, it is clear that the mainte- nance of the efficiency of the apparatus requires that the spring s shall from time to time be adjusted, so as to be kept in that relation to its antagonistic forces, which are necessary for the due performance of the telegraph. It has been already shown that very sufficient and very simple means of adjustment for this purpose have been supplied in the French telegraphs. The hands which appear in the upper corners of the instrument (fig. 70) are intended for this purpose, and being turned by the key, the springs connected with them are increased or diminished in their force, according as the key applied to them is turned the one way or the other. Similar adjustments are provided in the German instruments. 32 Fig. 81. FROMENT'S ALPHABETICAL TELEGRAPH. THE ELECTRIC TELEGRAPH. CHAPTEE IX. 201. Defects of the French and German instrument removed by Lippens' instrument. 202. Description of it. 203. Its wheel commutator. 204. Transmission of despatches by it. 205. Froment's alphabetic telegraph. 206. Morse's telegraph. 207. Froment's writing tele- graph. 208. Bain's chemical telegraph. 209. Method of writing. 210. Electro-chemical pen. 211. Metallic desk. 201. M. Lippens and the Belgian railway and telegraph authori- ties by whom he has been supported, however contend, that although the permanent staff of the state and public telegraphs constantly occupied and practised in the manipulation of such apparatus may be relied upon for the due management of such adjustments, the agents of various grades employed on the rail- ways, whose duties do not permanently connect them with the telegraph, and who are only called to it from time to time, cannot be depended on to perform adjustments requiring not only con- stant practice, but some address and some special knowledge of the principle and mechanism of the apparatus. LARDXER'S MUSEUM OP SCIENCE. D 33 No. 43. THE ELECTRIC TELEGRAPH. The apparatus of M. Lippens, which is now used for the service of the Belgian railways, is exempt from these defects. Like M. Siemens, M. Lippens rejects the mainspring and its appendages adopted in the French telegraphs, and charges the current itself with their functions. He retains, however, the commutator, and imparts the pulsations to the current by the hand of the agent applied to a lever or winch, which is moved exactly like the arm of the commutator of the French instruments. He rejects the spring 5 (fig. 77), which produces the recoil of the armature, and substitutes for it a second magnet placed on , the other side of the armature, substituting at the same time a permanently magnetic bar of steel for the armature of soft iron used in the other instruments. 202. To explain the principle of Lippens' apparatus, let a I and a* b' (fig. 78) be two electro-magnets made precisely alike, the Fig> 78t coil of covered wire upon them being one continuous wire carried from one to the other, and rolled in such a manner that their po- larity shall always have contrary positions in whichever direction the current may be trans- mitted on the wire. Thus, if a be a north pole, b f opposed to it will be a south pole, and in that case a' will be a north and b a south pole. If the current upon the coil be reversed, all these four poles will at once change their names a becoming a south and b' a north pole, and a' a south and b a north pole. Let g g f be a steel bar which is permanently magnetised, g being its north and (f its south pole, and let it be supported midway between the electro-magnets, having free play towards the one or the other until it encounters the stops it or if V by which it is arrested. Now let a current be transmitted upon the wire, by which a will become a north pole, and consequently b and b' will be south poles, and a' a north pole. Since g is a north and $ a south pole, they will be attracted by b' and a', and repelled by a and b, and consequently the armature g g 1 will be moved towards b' a' until it is stopped by t' f. If the current be then reversed, a and a' will become south, and b and b' north poles ; and the armature BELGIAN EAILWAY TELEGRAPH. will be attracted by a and b, and repelled by 6' and a', and will accordingly move towards the latter until it is stopped by 1 1. If the direction of the current be reversed rapidly, suppose, for example, ten times per second, the armature g g' will be made to oscillate ten times per second between the stops 1 1 and f f. It is evident that the expedient adopted by Siemens, by which the transmission of the current is arrested by the contact of the armature with one stop and re-established by its contact with the other, might be easily modified so as to reverse the direction of the current by each contact with 1 1 and f t' ; and in that case the telegraph of Siemens would without other change be ren- dered exempt from the defects imputed to it, as well as the French instruments, by Lippens. But M. Lippens, either prevented from adopting this obvious expedient by the patent of Siemens, or giving a preference to the hand commutator for other reasons, has contrived an ingenious commutator worked by hand, by which he reverses the current with the greatest facility, rapidity, and precision. 203. This is a wheel commutator formed on the principle ex- plained in 129, but there are two wheels such as are there described placed one upon the other upon a common axle, with a disc of gutta percha between them, so that one is insulated from the Fig. 79. other. The edges of both are divided into a series of conducting and non-conducting arcs, but the position of these relatively to each other is alternate, the conducting arcs of each disc corre- sponding in position with the non-conducting arcs of the other. We may imagine the shaded arcs of fig. 79 to represent the conducting arcs of the upper, and the white arcs the conducting arcs of the lower disc, the one, however being separated from all contact with the other by the interposed disc of gutta percha. D 2 35 THE ELECTRIC TELEGRAPH. When the wheel is made to revolve, the spring / comes alter- nately into contact with the conducting arcs of the one and of the other disc. Another similar spring is applied to another part of the edge of the wheel, so as to be in contact with the conducting arcs of the upper disc, while the spring i j is in contact with those of the lower, and vice versa. One of the two discs is in connection with the copper, and the other with the zinc end of the battery, so that one may be con- sidered as its positive and the other as its negative pole. One of the springs is in connection with one end, and the other with the other end of the conducting wire, which forms the coils, and which passes along the telegraphic line. By causing the wheel to revolve, therefore, the conducting wire will be alternately connected with contrary poles of the battery, and the current upon it will be reversed. If the edge of the wheel be divided into ten equal parts by the conducting arcs, this reversion will take place ten times in each revolution, and if a revolution be imparted to the wheel in each second, the current will be reversed ten times per second. In the apparatus of Lippens the oscillations thus imparted to the armature, g g', fig. 78, are made to act by the intervention of toothed wheels upon the indicating hand which moves upon the dial around which the letters are engraved, as in the French tele- graph, and this hand is moved from letter to letter in the same manner as in the French railway telegraph and that of Siemens. Upon the axle of the commutating wheel above described a winch is fixed by which the agent who transmits the despatch turns it. A plan of this instrument is drawn in fig. 80. The handle of the commutator B B' is keyed upon the axis of the wheel already described, which is under the table of the instrument. This wheel, and the springs which press upon it, are indicated in the figure. The handles Q Q are those by which the current is conducted from the up or down line through the indicating apparatus, or through the alarum, as already explained in the case of the German telegraph. Several other batteries are provided for establishing connections with the line wires, the battery poles, the alarums, and the earth, and differ in nothing essential from similar adjustments in other telegraphic instruments. 204. When the agent at any station, s, desires to transmit a despatch to any other station or stations, s', he first, as in other telegraphs, calls the attention of the agents at s' by means of the alarum. The current being then directed through the instru- ments severally by means of the adjustments provided for that purpose, the transmitting agent at s turns the handle B B' of his 36 BELGIAN RAILWAY TELEGPwVPH. commutator, by which he produces the pulsations of the current, and puts the indicating hands upon the dials at s', as well as upon his own in motion. These hands as usual, when properly Fig. 80. adjusted always point to the same letters. The transmitting agent stops the handle B B' when he sees the hand F upon his dial point successively to the letters which spell the word he 37 THE ELECTRIC TELEGRAPH. desires to transmit, and by continuing to operate thus, he transmits the entire despatch. Such is the Belgian railway telegraph, and although it must he admitted that it supplies a certain improvement on the French telegraph, it ought also to he stated that the difficulty and incon- venience which M. Lippens claims to have removed, has not heen found to offer any practical obstruction to the satisfactory per- formance of the French instruments. It appears that M. Lippens has lately made considerable im- provements in the practical details of his telegraph, by which its operation is rendered much more convenient. He has also sub- stituted the magneto-electric for the voltaic current, and thus dispensed with the voltaic battery. This last improvement has not yet (July, 1854) been applied on the telegraphic lines, but will be in operation, probably, before these pages come into the hands of the reader. FEOMEXT'S ALPHABET TELEGUAPH. 205. The external appearance of this instrument, represented in fig. 81 (p. 33), is that of a small piano-forte, having, however, no black keys. On each of the keys a letter of the alphabet is engraved, the first key being marked with a cross, and the last with an arrow. On the first ten keys are also engraved the numerals. This part of the apparatus is the commutator, by which the agent at the station where it is placed, is enabled to transmit signals to any distant station. Upon it is placed the indicating apparatus, which is acted upon by the commutator of the apparatus at a distant station, and by which a despatch is received. This indicator is similar in form and in the manner of giving its signals to that of the French railway telegraph already described. The dial of the indicator is marked with the letters of the alphabet, and the cross and arrow corresponding with the characters engraved upon the keys of the commutators. At the back of the case containing the indicating apparatus the alarum is attached, and commutators are placed upon the case by which this alarum can be put in connection at pleasure with the line-wire. As usual it is always kept in connection with it when the instrument is not in use, so that notice may be given of the approaching arrival of a despatch. On the ringing of the alarum the agent at the station turns off the commutator from the alarum and throws it into connection with the indicating apparatus. To explain the tranmission of a despatch, let us suppose an apparatus, such as that represented in the figure, to be erected 38 FKOMENT'S ALPHABETIC TELEGRAPH. at two stations, s and s', connected as usual by a conducting wire ; the instrument, being unemployed, the line- wire at both is in connection with the alarum. Now let us suppose that s desires to transmit a despatch to s'. In that case s having first turned on the current, puts down any key whatever of his commutator, the effect of which is that a current is transmitted upon the line wire to s', which rings the alarum; then s' replies by transmitting a return current in the same way to s, by which s's alarum is rung. All being then prepared for the trans- mission of the despatch, s puts down with his fingers succes- sively the keys of his commutator upon which the successive letters spelling the words of the despatch are engraved, and simultaneously with this the indicator upon the dial of s' points to the same letters, which are taken down by s'. At the end of each word, s puts down the key marked with the cross. "When it is intended to transmit numerals, s puts down the arrow just before he begins them, and the cross when he ends them. Thus if it be desired to transmit the number 1854, s first puts down the arrow, and then the keys marked A, H, E, and D succes- sively, after which he again puts down the cross to indicate that the number is finished. It remains now to explain how these effects are produced. Within the case, and at some distance below the key-board, a steel rod is extended, parallel to the line of keys, the length of which corresponds with that of the row of keys. From this rod, and at right angles to it, proceeds a series of short steel arms, one under each key. In the bottom of each key, and at right angles to it, is inserted a short projecting pin, which corresponds pre- cisely in position with the short steel arm just mentioned. The length of the arm, and that of the pin, taken together, is a little less than the distance between the bottom of the key and the steel rod when the key is not put down by the finger, the neces- sary consequence of which is that in that position of the key the rod may revolve, carrying the arm round with it unobstructed. But when the key is put down by the finger, the bottom of it is brought to a distance from the rod which is less than the sum of the lengths of the projecting arm and the pin, and consequently if the rod revolves, carrying with it the projecting arm while the key is thus held down, the pin coming in the way of the arm arrests it, and stops the further revolution of the steel rod. It is evident that if the projecting arms were all inserted in the teel rod at the same side, or to speak with still more precision, if their points of insertion lay in a line along the side of the rod parallel to its axis, the pins of all the keys would arrest the revolution of the rod in exactly the same position, and, as it 39 THE ELECTEIC TELEGEAPH. will presently appear, that the position in which the rod is stopped determines the signal transmitted, it would follow as a consequence that in such case all the keys would transmit the same signal, and the indicator at the station to which the dispatch is to be transmitted would always return to the same letter upon the dial. To prevent this, and to vary the signal in the necessary manner, the projecting arms are inserted in the steel rod according to a spiral or heliacal line, surrounding it like the thread of a screw, so that if, for example, the rod be placed so that the first projecting arm corresponding to the key marked with the cross, points directly upwards, the fourteenth which corresponds to the key M, will point directly downwards, and the intermediate arms will point at angles more and more inclined from the upward direction, each being deflected from the upward direction more than the preceding one by the fourteenth part of the half circumference. In like manner, in proceeding from the arm corresponding with the key M, which points downwards, each successive arm will be more and more deflected from the downward direction, each being more deflected from it than the preceding one by the fourteenth part of half the circumference. Thus the twenty-eight projecting arms divide the circumference of the rod into twenty-eight equal parts, and consequently in a revolution of the rod, the arms come successively to the position in which they point upwards and in which they would encounter the pin projecting from the bottom of the key if that pin were thrown in their way by the key being pressed down by the finger. It will be evident, therefore, that if from any cause the steel rod be made to revolve, its motion may be stopped at twenty-eight different points of its complete revolution by means of the depres- sion of the twenty-eight keys. We shall now show how a motion of revolution is imparted to this rod. To its right-hand extremity is fixed a ratchet-wheel, which is in connection with a train of clockwork, moved in the usual manner by a mainspring. This clockwork is contained within the case of the apparatus. If it be wound up, and if nothing obstructs its action, a motion of continuous rotation will be im- parted to the ratchet-wheel, and by it to the steel rod, and this motion will be more or less rapid according to the force of the mainspring, and the adjustment of a fly which is connected with it. They are so adjusted as to cause the rod to revolve two or three times in a second. But in the teeth of the ratchet-wheel, a catch is inserted, which counteracts the mainspring and preventf the motion, which can only take place when this catch is with- drawn. A bar is suspended parallel to the keys, and under them, by a contrivance called in mechanics a parallel motion, by meana 40 MORSES TELEGRAPH. of which any of the keys when pressed by the finger will lower it. This bar rests upon the arm of the catch engaged in the teeth of the ratchet-wheel, so that whenever any key is put down by the finger, the bar is depressed, the catch disengaged, the wheel liberated, and a motion of revolution imparted. On the left hand extremity of the steel rod is fixed a commu- tating wheel, similar in principle to that already described in the railway telegraph. This wheel, being fixed upon the rod, turns with it, moving when it moves, and stopping when it stops. Since the position in which the rod stops is determined by the key put down, the position in which the wheel thus fixed on the rod stops, is similarly determined. This wheel determines the pulsation of the current, and these pulsations determine the position of the indicator at the station to which the despatch is transmitted, in a manner which is substantially the same as that already described in the case of the railway telegraph. FOSSE'S TELEGKAPH. 206. This apparatus, which is applied on an extensive scale in America, and with some slight modifications in the Germanic States, is constructed upon the principle already explained in 153. Fig. 82. A general view of the instrument in its most usual form is- given in fig. 82. i is the electro-magnet ; H is an armature working on the centre c ; i an adjusting screw to limit the play of the armature, and prevent its contact with the electro-magnet at p ; d another adjusting screw to limit its play in the other direction ; t a metallic 41 THE ELECTRIC TELEGRAPH. style which marks by pressure a band or ribbon of paper drawn from the roll R, and carried between the rollers o and o' ; P the ribbon of paper discharged from the rollers o o', after being impressed by t with the telegraphic characters ; I, &, &c., clock- work from which the rollers o o' receive their motion, by which motion the ribbon of paper is drawn from the roller K ; / the spring which draws the arm H of the electro-magnet from the armature ; s s the upright pieces supporting the clockwork ; B B the base supporting the instrument ; D, the key commutator, by which the current transmitted along the line-wire is alternately transmitted and suspended ; m, w, w', n', wires by which the coil of the electro-magnet and the poles of the station battery are put in connection with the line-wires. The general principle of this and all similar apparatus has been already so fully expained in 153, et seq., that little more need be said here to render it intelligible. If it be desired to transmit a despatch to a distant station, the battery at the trans- mitting station is put in communication with the line-wire, and by the action of the key D the current is alternately transmitted and suspended during longer and shorter intervals, which are determined by the conventional telegraphic letters. The action of the style t against the ribbon of paper which passes over it at the station receiving the despatch, corresponds exactly with the action of the key D at the station from which the despatch is transmitted ; and combinations of longer and shorter marks or lines and dots are produced upon the ribbon of paper by its pressure, as is shown in the figure. The particular combinations of lines and dots used to express the letters are obviously arbitrary. As a matter of convenience and means of expedition, the letters of most frequent occurrence are expressed by the most simple signs, and consequently the selection of signs for the different letters will vary with the language in which the dispatch is expressed. The following are the telegraphic characters adopted by Mr. Morse for the English language : A - B J K ^ S --- T Numerals. A D E - p M N - - - p . V w X Y - - - - - 3 4 .... 5 g H I -- 2: -.r Z --- - & - --- 7 8 42 MORSE'S TELEGRAPH. This telegraphic apparatus being that which has been by far the most extensively brought into use, being not only adopted almost exclusively in the United States and contiguous countries, but also in all the German States, it may' be useful here to present the instrument and its appendages in the form in which it has been most recently constructed in the United States, and which has been recommended by the American telegraphic confederation, as being that which it would be most advantageous to adopt gene- rally, so that all the parts being manufactured of the same pattern and size no difficulty would be found in replacing any of them in case of fracture. A perspective view of the instrument, omitting the paper roller and ribbon, is given in fig. 83 (p. 44). z. The wooden base upon which the instrument is screwed, B. The brass base plate attached to the wooden base z. A. The side frames supporting the mechanism. A, h. Screws which secure the transverse bars connecting the side frames. G. The key for winding up the drum containing the main- spring, or supporting the weight, according as the mechanism is impelled by one or the other power. 3, 4. Clock-work. w, A lock or gauge to regulate the pressure of the rollers on the paper. c. The pillar supporting the electro-ma|net. p. The adjusting screw passing into the pillar, c, projecting through the armature, to enable the telegraphist to adjust the sound of the back stroke of the armature at pleasure. 0. The spring bar, and d, the screw to adjust the action of the pen lever. D. The apparatus for adjusting the paper rollers. /. The adjusting screw of the pen lever. The form of the relay magnet recommended, is given in fig. 84 (p. 45), in its proper size. A B, are the helices or coils, c. The supporter of the magnet lightly screwed to w, the connecting bar of the magnets. Y. Rosewood or ivory ends of magnets. D, Armature screwed to E, an upright lever ; F, its axis, surrounded by a spiral spring, to perfect the con- nection in case of a fault at the ends of the axle. M. The spring to produce the recoil of D and E. 1. Its adjusting screw. 3. An adjusting screw to limit the play of E towards the magnet; 43 MORSE S TELEGRAPH. E, its point of platinum. s. An adjusting screw to limit the play of E from the magnet. T. Its insulating point, in ivory. o isr. Screws to connect with the wires of the station battery. Fig. 84. p Q. Screws to connect with the line wires. x. The point where the coil wire passes through u, the base of the magnet. The form recom- mended for the key commutator is re- presented in its proper magnitude in fig. 85 (p. 46). When the key is held down the circuit is per- fect. It is not liable to wear and to pro- duce a doubtful connection. The ' whole arrangement is designed to avoid the evils heretofore existing, and perfect every questionable part. The anvil of the key is well made, firm, and capable of hard wear, regardless of the adjustment of the key lever. The hammer of the key lever is also firm, and made of good platina wire, and securely made fast in the key lever. The adjusting screws of the axle are arranged according to the best mode, to secure the most perfect action. The elevation of the key lever can be adjusted to suit the operator, by elevating the key frame, or otherwise. 45 THE ELECTRIC TELEGRAPH. Fig. 85. FROMENT'S WHITING TELEGRAPH. 207. This apparatus is represented in fig. 86 (p. 49), and the principle on which it acts has been fully explained in (153). The paper upon which the telegraphic characters are written is rolled upon the surface of a drum c. The pencil & is pressed by a spring upon the paper. The drum is made to revolve by clock- work in the usual manner contained in the case 7i. If the paper be moved without moving the pencil, the latter will trace a straight line ; but if the pencil be moved to and fro by the action of the electro-magnet and recoil spring, a zigzag line will be formed by the vibrations imparted to the pencil by the magnet, or what is the same, by the pulsations of the current. To equalise the wear of the pencil, a slow motion of rotation is imparted to it by wheels adapted for that purpose. The commutator by which the pulsations which determine the signals are produced, is a wheel, at the circumference of which are five metallic divisions with intermediate spaces vacant, so that in each revolution the current is transmitted five times, and suspended five times. If it be desired to produce a single pulsa- tion, the wheel is moved through the fifth part of a revolution ; if it be desired to produce three pulsations it is moved through three-fifths of a revolution, and 'so on. For each pulsation, one zigzag is made by the pencil at the station to which the despatch is transmitted. The signs adopted in this telegraph to express the letters, are various numbers and combinations of zigzag forms. BAIN'S ELECTRO-CHEMICAL TELEGRAPH. 208. The manner in which the decomposing power of the current is capable of producing written characters at a distance from the hand of the writer has been already explained (170). 46 BAIN'S ELECTRO-CHEMICAL TELEGRAPH. Of the forms of telegraph in which this principle is brought into play, the only one which has been practically applied on an extensive scale is that projected by Mr, Alexander Bain. 209. To render this instrument understood, let us suppose a sheet of writing paper to be wetted with a solution of prussiate of potash, to which a little nitric and hydrochloric acid have been added. Let a metallic desk be provided corresponding in magni- tude with the sheet of paper, and let this desk be put in com- munication with a galvanic battery so as to form its negative pole. Let a piece of steel or copper wire forming a pen be put in con- nection with the same battery so as to form its positive pole. Let the sheet of moistened paper be now laid upon the metallic desk, and let the steel or copper point which forms the positive pole of the battery be brought into contact with it. The galvanic circuit being thus completed, the current will be established, the solution with which the paper is wetted will be decomposed at the point of contact, and a blue or brown spot will appear. If the pen be now moved upon the paper, the continuous succession of spots will form a blue or brown line, and the pen being moved in any manner upon the paper, characters may be thus written upon it as it were in blue or brown ink. An extremely feeble current is sufficient to produce this effect ; but it will be necessary, when the strength of the current is very much reduced, to move the pen more slowly, so as to give the time necessary for the weakened current to produce the decom- position. In short, a relation exists between the greatest speed of the pen which is capable of leaving a mark, and the strength of the current ; the stronger the current the more rapidly may the pen be moved. In this manner, any kind of writing may be inscribed upon the paper, and there is no other limit to the celerity with which the characters may be written, save the dexterity of the agent who moves the pen, and the sufficiency of the current to produce the decomposition of the solution in the time which the pen takes to move over a given space of the paper. 210. The electro-chemical pen, the prepared paper, and tbe metallic desk being understood, we shall now proceed to explain the manner in which a communication is written at the station where it arrives. 211. The metallic desk is a circular disk, about twenty inches in diameter. It is fixed on a central axis, with which it is capable of revolving in its own plane. An uniform movement of rotation is imparted to it by means of a small roller, gently pressed against its under surface, and having sufficient adhesion with it to cause the movement of the disk by the revolution of 47 THE ELECTRIC TELEGRAPH. the roller. This roller is itself kept in uniform revolution by means of a train of wheel- work, deriving its motion either from a weight or main spring, and regulated by a governor or fly. The rate at which the disk revolves may be varied at the discretion of the superintendent, by shifting the position of the roller towards the centre ; the nearer to the centre the roller is placed, the more rapid will be the motion of rotation. The moistened paper being placed on this disk, we have a circular sheet kept in uniform revolution. The electro-chemical pen, already described, is placed on this paper at a certain distance from its centre. This pen is sup- ported by a pen-holder, which is attached to a fine screw ex- tending from the centre to the circumference of the desk in the direction of one of its radii. On this screw is fixed a small roller, which presses on the surface of the desk, and has sufficient adhesion with it to receive from it a motion of revolution. This roller causes the screw to move with a slow motion in a direction from the centre to the circumference, carrying with it the electro-chemical pen. "We have thus two motions, the circular motion carrying the moistened paper which passes under the pen, and the slow rectilinear motion of the pen itself directed from the centre to the circumference. By the combination of these two motions, it is evident that the pen will trace upon the paper a spiral curve, commencing at a certain distance from the centre, and gradually extending towards the circumference. The intervals between the successive coils of this spiral line will be determined by the relative velocities of the circular desk, and of the electro-chemical pen. The relation between these velocities may likewise be so regulated, that the coils of the spiral may be as close together as is consistent with the distinctness of the traces left upon the paper. A view of the circular desk, the chemical pen, and the clock- work is given in fig. 87 (p. 65), which will render the preceding explanation more easily understood. 43 Fig. 86. FROMENT'S WRITING TELEGRAPH. THE ELECTRIC TELEGRAPH. CHAPTEE X. 212. Operation of Bain's telegraph. 213. Its commutator. 214. Its extraordinary speed of transmission. 215. Obstructions to its practical application. 216. Its prospects. 217. Autograph telegraph. 218. House's printing telegraph. 219. Its operation. 220. Henley's magnetic telegraph. 221. Brett's printing telegraph. 222. Celerity of telegraphic communication. 223. Circumstances which affect it. 224. Comparative ability of telegraphists. 225 Each telegraphist known by his manner of transmitting. 226. Easier to transmit than to receive. 227. Pauses in transmission. 228. Rate of transmission with double needle instruments worked by voltaic current. 229. Rate with magneto-electric current. 212. Now, let us suppose that the galvanic circuit is completed in the manner customary with the electric telegraph, that is to say, the wire which terminates at the point of the electro-chemical pen is carried from the station of arrival to the station of de- parture, where it is connected with the galvanic battery, and the returning current is formed in the usual way by the earth itself. When the communication between the wire and the gal- vanic battery at the station of departure is established, the current will pass through the wire, will be transmitted from the point of the electro-chemical pen to the moistened paper, and will, LARDNER'S MUSEUM OP SCIENCE. K 49 No. 45. ELECTRIC TELEGEAPH. as already described, make a blue or brown line on this paper. If the current were continuous and uninterrupted, this line would be an unbroken spiral, such as has been already described ; but if the current be interrupted at intervals, during each such interval the pen will cease to decompose the solution, and no mark will be made on the paper. If such interruption be frequent, the spiral, instead of being a continuous line, will be a broken one, consisting of lines interrupted by blank spaces. If the current be allowed to act only for an instant of time, there will be a blue or brown dot upon the paper ; but if it be allowed to continue during a longer interval, there will be a line. Now, if the intervals of the transmission and suspension of the current be regulated by any agency in operation at the station of departure, lines and dots corresponding precisely to these intervals, will be produced by the electro-chemical pen on the paper, and will be continued regularly along the spiral line already described. It will be evident, without further explana- tion, that characters may thus be produced on the prepared paper corresponding to those of the telegraphic alphabet already de- scribed in the case of Morse's telegraph, and thus the language of the communication will be 'written in these conventional symbols. There is no other limit to the celerity with which a message may be thus written, save the sufficiency of the current to effect the decomposition while the pen passes over the paper, and the pOAver of tHe agency used at the station of departure to produce, in rapid succession, the proper intervals in the transmission and suspension of the current. The succession of intervals of transmission and suspension of the current on which the production of the written characters on the prepared paper depends, may obviously be produced by the key commutator (128),; and with that instrument at the station from which the dispatch is transmitted, an agent can convey in the same manner and with the same celerity as in the case of the telegraph of Morse, or that of Froment ; and such is in fact the manner in which dispatches are usually transmitted with this apparatus. 213. But this form of commutator, though perfectly efficient so far as it goes, does not call into operation all that extra- ordinary celerity which forms the prominent feature of this invention, and of which a remarkable example has been already mentioned in the case of the experiments performed by M. Le Terrier and myself before the Committees of the Institute and the Legislative Assembly at Paris, which were made with these instruments, and, as we have stated, dispatches were 50- BAINS CHEMICAL TELEGRAPH. sent along a thousand miles of wire, at the rate of nearly 20000 words an hour. We shall now explain the means by which this extraordinary feat is accomplished. The despatch must pass through the fol- lowing preparatory process : A narrow ribbon of paper is wound on a roller, and placed on an axis on which it is capable of turning so as to be regularly unrolled. This ribbon of paper is passed between rollers under a small punch, which striking upon it makes a small hole at its centre. This punch is worked by a simple mechanism so rapidly, that when it is allowed to operate without interruption on the paper passing before it, the holes it produces are so close together as to leave no unperforated space between them, and thus is produced a continuous perforated line. Means, however, are pro- vided by which the agent who superintends the process, can, by a touch of the finger, suspend the action of the punch on the paper, so as to allow a longer interval to elapse between its successive strokes upon the paper. In this manner a succession of holes are perforated in the ribbon of paper, separated by unperforated spaces. The manipulator, by allowing the action of the punch ;to continue uninterrupted for two or more successive strokes, can make a linear perforation of greater or less length on the ribbon, and by suspending the action of the punch these linear perforations may be separated by unperforated spaces. Thus it is evident, that being provided with a preparatory apparatus of this kind, an expert agent will be able to produce on the ribbon of paper as it unrolls, a series of perforated dots and lines, and that these dots and lines may be made to correspond with those of the telegraphic alphabet already described. Let us imagine, then, the agent at the station of departure pre- paring to despatch a message. Preparatory to doing so, it will be necessary to inscribe it in the perforated telegraphic characters on the ribbon of paper just described. He places, for this purpose, before him the message in ordinary writing, and he transfers it to the ribbon in perforated characters by means of the punching apparatus. By practice he is enabled to execute this in less time than would be requisite for an expert compositor to set it up in common printing type. The punching apparatus for inscribing in perforated characters the dispatches on ribbons of paper is so arranged, that several agents may simultaneously write in this manner different mes- sages, so that the celerity with which the messages are inscribed on the perforated paper may be rendered commensurate with the rapidity of their transmission by merely multiplying the inscribing agents. E2 51 ELECTRIC TELEGRAPH. Let us now imagine the message thus completely inscribed on the perforated ribbon of paper. This ribbon is again rolled as at first upon a roller, and it is now placed on an axle attached to the machinery of the telegraph. The extremity of the perforated ribbon at which the message commences is now carried over a metallic roller, which is in con- nexion with the positive pole of the galvanic battery. It is pressed upon this roller, as represented in fig. 88, by a small Fig. 83. metallic spring, terminating in points like the teeth of a comb, the breadth of which is less than that of the perforations in the paper. This metallic spring is connected with the conducting wire which passes from the station of departure to the stations of arrival. When the metallic spring falls into the perforations of the ribbon of paper as the latter passes over the roller, the galvanic circuit is completed by the metallic contact of the spring with the roller ; but when those parts of the ribbon which are not perforated pass between the spring and the roller, the galvanic circuit is broken and the current is interrupted. A motion of rotation, the speed of which can be regulated at discretion, is imparted to the metallic roller by clockwork or other means, so that the ribbon of paper is made to pass rapidly between it and the metallic spring, and, as it passes, this metallic spring falls successively into the perforations on the paper. By this means the galvanic circuit is alternately completed and broken, and the current passes during intervals corresponding precisely to the perforations in the paper. In this manner the successive intervals of the transmission of the current are made to correspond precisely with the perforated characters expressive of the message, and the same succession of intervals of transmission and suspension will affect the writing apparatus at the stations of arrival in the manner already described. 214. Now there is no limit to the speed with which this process can be executed, nor can there be an error, provided only that 52 BAIN'S CHEMICAL TELEGRAPH. the characters have been correctly marked on the perforated paper ; but this correctness is secured by the ribbon of perforated paper being examined after the perforation is completed and deliberately compared with the written message. Absolute accuracy and unlimited celerity are thus attained at the station of departure. To the celerity with which the dispatch can } be written at the station of arrival there is no other limit than the time which is necessary for the electric current to produce the decomposition of the chemical solution with which the prepared paper is saturated. 215. It may be asked then why this form of telegraph, affording as it does the means of obtaining a celerity of transmission so far exceeding any other that has been projected, has not been universally adopted ? To this it may be answered that the celerity here described can only be attained after the dispatch to be transmitted has been marked in the pierced telegraphic characters on the ribbon of paper, and that the process of so marking it would not be more rapid, however expert the operator might be, than that by which the same operator would transmit the same dispatch directly by the key commutator, either with this telegraph or those described in (191, 192). If, therefore, the time necessary to commit the dispatch in telegraphic characters to the perforated ribbon of paper, be included in the estimate of the time of its transmission from station to station, this form of telegraph is not only slower and consequently less efficient than either of those described in (191, 19,2), but it is slower than any other form of telegraph whatever. It must therefore be admitted, that, so long as the demands upon the conducting wires do not exceed their powers of transmission by the operation of the ordinary methods now commonly practised, the contrivance of Mr. Bain can present no very strong claims for preference over the other systems. But if the demands of the public should be greatly multiplied, as they certainly would be by lowering the tariff, then the method above described would be presented under different conditions, and might become the only expedient of all those hitherto contrived, by which such augmented demands could be satisfied. 216. If for example the time should arrive when a much more considerable share of the demands now satisfied by the post-office should be transferred to the telegraph; if instead of short and unsatisfactory dispatches conveying political and general intel- ligence to the journals, fully detailed circumstantial statements and reports were required ; if the same full reports of speeches and debates, on occasions of great public interest, or reports of any 53 ELECTKIC TELEGRAPH. proceedings or events of adequate importance, taking place at a distance, which are now transmitted through the post-office were required to be sent by telegraph, it is clear that the apparatus now in common use, of whatever form, would be utterly inadequate to the satisfaction of such demands. But how, it will be asked, would the system of Bain be more efficient? The answer is obvious. Nothing more would be necessary than to engage a greater number of persons for the purpose of committing the dispatches to the perforated ribbons. If a great number of dispatches, short or long, be brought at once into the telegraphic office for transmission, let them be imme- diately distributed among a proportionate number of the persons engaged in the preparation of the ribbons. A long dispatch might be divided into several portions, and distributed among several, just as a manuscript report intended for publication in a journal is distributed among several compositors. When the despatches thus distributed should be committed to the ribbons, these ribbons might be connected together so as to form longer continuous ribbons, which being put into the telegraphic instru- ments would be sent to their destination at the rate of 20000 words an hour on each wire. A mercantile firm, or the correspondent of a journal might, if they were so minded, have their own punching apparatus and their own telegraphic cipher, and instead of sending to the telegraphic- office a manuscript dispatch they would send a ribbon of paper containing the dispatch marked upon it, which being put directly into the instrument would be instantly transmitted to its destina- tion. And this would be attended with the further advantage that the contents of the dispatch would be concealed from the agents themselves employed in its transmission. The party to whom the dispatch is addressed would in this case receive the sheet taken from the instrument written in the cipher of which he alone would possess the key. It often happens, especially in the business of government or that of journalism, that the same dispatch is required to be transmitted to many different places in different directions. By the system of Bain this would be easily accomplished. The same ribbon which sends the dispatch in one direction may be transferred imme- diately to another instrument acting upon another line of wire, or even remaining in the same instrument the transmission may be repeated, changing the direction by a commutator. If it were required no great difficulty would be presented by the process of perforating two or more ribbons at once with the same dispatch. The process would not be slower than that required for a single ribbon, and in that case the several ribbons might be 54 HOUSES TELEGRAPH. at the same time sent to different telegraphic stations, and their contents transmitted in various directions. In this view of the question, the system of Bain is to the com- mon telegraph what the steam-engine is to the horse, the power to the hand-loom, the lace-frame to the cushion, the self-acting mule to the distaff, or the stocking-frame to the knitting-needle. 217. A modification of the electro-chemical telegraph has been contrived, by which a dispatch may be transmitted to any distant station, and then delivered in the handwriting of the person who transmits it. By this method, a person at any station, as for example at London, may write a communication in characters used in common writing or printing on paper placed at another distant station, as for example at Trieste, and this writing shall be traced on the paper with as much precision as if the person writing held the pen in his hand. We may imagine that the electro-chemical pen placed on the paper at Trieste is extended to London, and there held and directed by the hand of the writer, for this it is which almost literally takes place. The conducting wire, in connection with that part of the electro-chemical pen which is held in the hand, which extends from Trieste to London, may be considered as only forming part of this pen, and the end of such pen at London, held and directed by the hand of tlie writer, will communicate a motion to its point at Trieste, in exact correspondence with the characters formed by the hand of the writer. Thus, if the writer at London move the extremity of the con- ducting wire so as to write a phrase or his usual autograph, the point at Trieste will there inscribe on the prepared paper the same phrase with the same signature annexed, and the writing of the phrase and the signature will be identical with that of the writer. In the same manner a profile or portrait, or any other outline drawing may be produced at a distance. The methods of accom- plishing this depend, like the other performances of electricity in this application of it, on the alternate transmission and suspension of the current, and on its Decomposing power ; but as they are at present more matters of curiosity than of practical utility, we shall not detain the reader here with any more detailed notice of them. HOTJSE'S TELEGEAPH. 218. This apparatus, which is in extensive use in the United States, is an example of the class of printing telegraphs, that is, 55 ELECTRIC TELEGKAPH. instruments which print in the ordinary letters the dispatch at the station to which it is addressed, by means of a power worked at the station from which it is transmitted. In a certain sense, this is accomplished by the three forms of telegraph described in (202, 203, and 204) ; but in these cases the dispatch is printed or written in cipher, which is attended with the inconvenience of being understood only by those who possess, and are sufficiently familiar with the key. The process of deciphering it, and writing it in common characters, occupying more or less time, for some purposes, such for example as that of journalism, this time must be taken into account in estimating the practical celerity of communications, inasmuch as the dispatch until so interpreted, is not available to the parties to whom it is addressed. A telegraph which instead of impressing on paper characters in cipher, would impress the characters of common letter-press, even though these should be transmitted and impressed at a slower rate than that of the transmission of the characters in cipher, might nevertheless be, in effect, more expeditious, more time being saved by superseding the process of interpreting the cipher than is lost by the relative slowness of the transmission. It is evident that these observations, being general, are applicable, not only to the instrument we are now about .to des- cribe, but to all others of the same class. 219. House's printing telegraph, like all other telegraphic instruments, consists of two distinct parts, a commutating apparatus to govern the transmission of the current, and a printing apparatus upon which the current arriving from a distant station operates. The manner in which the transmission of the current is con- trolled by the keys of the finger-board, is substantially the same as in Froment's telegraph already described. The wheel, how- ever, that produces by its revolution the pulsations of the current, is moved, not as in Froment's by clock-work, but by the foot of the operator, acting upon a treddle like that of a lathe which is seen under the case of the commutator in the fig. 89 (p. 81). The rotation of this wheel is arrested at the point corres- ponding to any desired letter, by putting down with the finger the key upon which that letter is engraved, in exactly the same manner and by the same mechanical expedient as in Froment's telegraph. The keys, upon the key-board of this instrument, govern by means of the pulsations of the current the motion and position of a dial or wheel at a distant station, inscribed with similar characters in the same manner as has been already explained in 56 HOUSES TELEGRAPH. the case of the French railway telegraphs, and in that of the telegraph explained in (201). Let us then suppose that by putting down any key, that inscribed with A for example at the station s, a certain dial or wheel at s', having upon it letters corresponding with those of the key-board at s, is so moved that the letter A is brought into a certain position. The letters upon this wheel are formed in relief like type, and when successively brought into the necessary position by the action of the current, having previously passed in contact with an inking apparatus, a band or ribbon of paper is pressed against them by means provided at the station s', and the impression of the letter is made upon the paper. By the next action of the current, the succeeding letter transmitted is brought to the same position, the ribbon of paper being meanwhile drawn forward, another impression takes place, and so on. The apparatus by which the ribbon of paper is moved, the type inked, and the paper pressed against it is not worked by the current. That process is effected by mechanism put in operation by the agent at the station at which the dispatch is received. In the figure, the ribbon of paper is represented at F, upon a roller from which it is gradually drawn, as letter by letter the words of the dispatch are impressed upon it. The black band which appears upon another roller is an endless strap by which the types are inked. In the mechanism as well of the transmitting as of the receiving apparatus, there are many details showing much ingenuity of contrivance, and resources of invention, which, however, are too complicated to admit of any clear exposition without numerous plans and sections, and which we must pass over. The printing apparatus, at the station at which the dispatch is received, is put in operation by the action upon the treddle, in the same manner as in the transmitting apparatus at the other station. The galvanic apparatus, which supplies the current for working this apparatus, is the battery of Grove, described in (34). About thirty cylindrical pairs are necessary for a distance of 100 miles. The first line operating with this apparatus was established between New York and Philadelphia in 1849. ELECTRIC TELEGRAPH. MAGNETIC NEEDLE TELEGRAPH. 220. The Magnetic Telegraph Company, retaining the needle indicators generally used in England, have rejected the galvanic "battery, and substituted the magneto-electric for the voltaic current. The instruments they have adopted are those which Fig. 90. were patented by Messrs. Henley and Forster, with some modi- iications. This form of telegraph, enclosed in its case, is shown in fig. 91 (p. 97), and divested of its case in fig. 90. The current is produced by electro-magnets, whose poles are moved in close proximity with those of strong compound per- manent magnets. These latter are represented at A (fig. 90). At their poles a straight piece of soft iron is placed, by the inductive influence of which the magnetism of the several bars composing the compound magnet is collected and combined. The electro- magnets are formed in the usual way, and are mounted on centres on which they are turned by levers, which project from either side of the case, so that the agent can work one with each hand. "When they have been pressed down by the hand they are raised to their former position by springs which are fixed on their axle. When these levers are pressed down, the electro-magnets are reversed in the relation of their poles to those of the permanent magnets, and momentary currents are transmitted on the con- ducting wires, and when the levers are observed to rise to their former position, momentary currents are again transmitted, but in a contrary direction. The currents thus transmitted on the line-wires are received at the station to which the dispatch is transmitted upon the coils of; electro -magnets, which are placed under the desk upon which the indicating needles are placed, and they impart temporary 58 HENLEY AND BRETT ? S TELEGRAPH. magnetism to these. These electro-magnets act upon a small permanent magnet suspended under the desk, on the axis of the indicating needle, and parallel to it. They deflect this needle on the one side or the other, at the moment they receive the magnetism from the current, and their deflection is continued by the effect of the induced magnetism produced by the permanent magnet on the electro-magnet. When the handle is raised, the momentary current being reproduced, but in the contrary direction, the polarity of the electro-magnet at the distant station is reversed, and the needle is deflected in the same manner to the other side. BRETT'S pRrsrTixa TELEGRAPH:. 221. Mr. Brett, who has obtained such well-merited celebrity by his successful exertions in establishing electric communication by- submarine cables between the United Kingdom and the continent of Europe, and more recently between the continents of Europe and Africa, took out, conjointly with Mr. House, a patent for a printing telegraph, the original form of which is represented in fig. 92 (p. 113). The apparatus, like that of House's American telegraph, already described, consists of a key-board, which is the transmitting apparatus or commutator, and does not differ in any important particular from that already described. The receiving and pointing apparatus is also very similar, and stands upon the key- board. In front of it is an indicating dial, the hand upon which points successively to the letters printed upon the scroll of paper by the apparatus behind the dial. The printing apparatus, with some modifications, is similar to that of House. This telegraph is, or was, lately exhibited at work in the Panopticon of Science, in Leicester Square. The Messrs. Brett are understood, however, to be engaged upon the construction of an instrument which is expected to attain the same objects in a more satisfactory manner. CELERITY OF TRANSMISSION". 222. Although it be true that the signals made at any one telegraphic station are rendered instantaneously apparent at another, no matter how distant, it must not therefore be inferred that the transmission of messages by the telegraph is equally instantaneous. Not only is this not the case, but the celerity with which messages are conveyed between station and station, so as to be rendered practically available for the purposes of intercommu- ELECTKIC TELEGRAPH. nication, differs very much when one form of telegraphic instru- ment or one pair of operators is compared with another. The profitable result of the operation of any telegraph is evidently measured by the number of words which it is capable of transmitting in such a shape as to be intelligible by the party to whom the message is addressed, in a given time. This, which we shall call the celerity of transmission, and which is quite distinct from the velocity with which electric signals are conveyed from station to station, is therefore a most important element in the estimation of the value of any telegraphic apparatus. 223. This celerity of transmission depends upon a great number of circumstances, several of which are independent of the tele- graphic apparatus. The principal of these are : 1. The skill and agility of the transmitting agent. 2. The quickness of eye, activity and attention of the receiving agent. 3. The instrument used for transmission. 4. The instrument used for reception. 5. The distance to which the dispatch is transmitted. 6. The insulation more or less perfect of the line wires. 7. The weather. With all and each of these conditions and qualities the celerity with which the dispatches are received and rendered available at their place of destination, varies, and with some of them this varia- tion extends to very wide limits. 224. Different telegraphists have very different powers as to celerity. These powers depend on practice as well as upon natural ability and aptitude, and on manual dexterity. Not only is it necessary to transmit the signals in quick succession, but to do so with such distinctness that they shall be readily interpreted, and such correctness as to render repetitions unnecessary. In this respect telegraphists having equal practice differ one from another as much as do clerks, some writing rapidly and legibly, some rapidly but not legibly, some legibly but not rapidly, and some neither rapidly nor legibly. The relative ability of tele- graphists in this respect is partly mental and partly mechanical, depending as much upon quickness of intelligence, attention, and observation, as upon manual dexterity and address. The great liability to delay, arising from the failure of the transmitter to render himself understood by the receiver, is ren- dered manifest by the fact that in all telegraphs conventional signs are established for the words, "wait," "repeat," "not understood," "understood," "proceed," and the like. When the transmitter is going on faster than the receiver can take down the words or understand them, then the latter remits the sign to 60 CELERITY OF TRANSMISSION. 11 wait," and if this sign is several times repeated, the necessity of proceeding slower is apparent. If the receiver mistakes a sen- tence, word, or letter, he remits the sign to " repeat." At the end of each sentence, he remits the sign " understood," and so on. Now it will be easily conceived that this necessity for frequent interchange of signs between the receiver and transmitter must affect, in an important degree, the celerity of transmission, and that its frequency must depend, not only on the abilities of the telegraphic agents, but also on the character of the signs trans- mitted by the instruments, according as they are more or less obvious and unequivocal. 225. It is a remarkable and very curious circumstance, that, independently of the mere celerity, clearness, and correctness of transmission with certain telegraphic instruments each tele- graphist has a manner and character, which is so peculiar to himself, that persons receiving his dispatch at a distant station, recognise his personality with as much certainty and facility as they would recognise the handwriting of a corre- spondent, or the voice and utterance of a friend or acquaintance, whom they might hear speak in an adjacent room. The agents habitually engaged at each of the telegraphic stations, in this way, soon become acquainted with those of all the other stations on the same line, so that, at tlje commencement of a dispatch, they immediately know who is transmitting it. While the aptitude of the transmitter is partly manual or mechanical, that of the receiver of a dispatch is not at all so. In some telegraphic instruments, as we have seen, the presence of a receiving agent is unnecessary, the dispatch being written or printed by the apparatus itself. In all instruments, however, which merely exhibit arbitrary signals, expressing letters, numbers, or words, the celerity must depend on the skill, aptitude, and quickness of eye of the receiver, to catch and commit to paper the succession of letters or words, as fast as the signals expressing them are produced before him. 226. In general, it is much more easy to transmit rapidly than to receive rapidly. The transmitter knows beforehand what signs he is about to produce, while each of them comes upon the receiver altogether unawares, and if, in the celerity of their suc- cession, one or more of them escape his eye, he is obliged either to guess at the missed letter or letters, which he can sometimes do with all the requisite clearness and certainty, or he must arrest the transmitter, which he does by giving the sign, " repeat," and so delay arises. In telegraphs which work by a series of visible signs, whether they be deflections of the needle, as in the English instruments, 61 ELECTRIC TELEGRAPH. attitudes of the arms, as in the French State instruments, or poin- ters directed *to the letters or figures on a dial, as in the railwajf instruments, the celerity of the transmission must be determined by the power of the less able of the two agents, the transmitter and receiver. If the transmitter be able to send the letters more rapidly than the receiver can read and take them down, he must moderate his pace to the limit determined by the power of his cor- respondent. If the receiver be capable of reading and taking down faster than the transmitter is able to send the letters, his superior force is useless. He can only write the dispatch as fast as he receives it. To send dispatches with the greatest advantage of celerity, the agents yoked to corresponding instruments ought to be selected of as nearly equal ability as possible, since the slower of a pair necessarily neutralises the superior skill of his fellow, and the dispatch would proceed with equal celerity if he were yoked with a less able correspondent. As quickness of hand is essential to the transmitter, quickness of eye is necessary to the receiver. 227. In all forms of telegraph which express the letters by signals, such as the needle telegraph, and the French State tele- graph, a certain pause is necessary between letter and letter, to prevent the signals being confounded one with another. In the single needle instrument, the letters being expressed by from one to four deflections of the needle, and in the double needle, from one to two, the mean time of each letter is that of two and a half deflections in the one, and one and a half in the other, the intervals between letter'and letter being the same in both. Owing to the slowness of transmission of the single needle instrument, it is only used between secondary stations, where there is but little business. It must, however, be remembered, in comparing the relative celerity of different instruments, that the double needle instrument, as well as the French State telegraph, is, in fact, two independent telegraphs, having not only separate and independent transmitting and indicating apparatus, with their respective accessories, batteries, &c., but separate and independent conduct- ing wires. It is, in effect, as if two equally powerful and inde- pendent steam engines were united in the same work, in order to obtain double power. 228. In 1850, Mr. Walker made some calculations, with the view to determine the average celerity of transmission at that time with the double needle instrument in the hands of compe- tent operators, and published the results in his work on electric telegraph manipulation. Eleven messages were timed, all of more than the usual length, the shortest consisting of 73 and the longest of 364 words. The total number of words was 2638, and, 62 CELERITY OF DOUBLE-KEEDLE TELEGEAPH. consequently, their average length was 240 words. The total time of transmission was 162 minutes, and, consequently, the average number of words transmitted, per minute, was 16|. The greatest speed of transmission was 201, and the least 8| words per minute. As it might be considered probable that four or five years' general experience and practice might have improved the ability of the operators, I applied to the secretary of the Electric Telegraph Com- pany, Mr. Foudrinier, requesting him to cause a sufficient number of messages, transmitted in the ordinary course of business with the double needle instrument, to be timed, which he was so obliging as to do, in June, 1854, and the following were the results : 11 Messages. Number of words in the addresses . .84 ,, ,, messages . . . 160 Total number of words transmitted . 244 Total time of transmission . . . .689 seconds. Average number of words transmitted per minute . . 21 1 It appears, therefore, that the average celerity of transmission with this instrument has increased in the ratio of about 16 to 21. The greatest celerity of transmission was, in this case, 24|, and the least 16| words per minute. 229. The manner in which the magnetic electric current affects the needle in the arrangement adopted by the Magnetic Telegraph Company, being somewhat different from that produced in the com- mon needle instruments, worked by the-Electric Telegraph.Company , although the systems of telegraphic signals are not essentially dif- ferent, it appeared to me to be not impossible that the difference between the instruments might more or less affect the celerity of transmission. I therefore requested Mr. Bright, the Secretary of the Magnetic Company, to time a series of dispatches transmitted in the ordinary course of business. This was accordingly done on the 28th of June, 1854, and the following were the results : 74 Messages. Total number of words .... 2792 Time of transmission . . . 102 m 8 s Average number of words per minute . . .27^ The greatest celerity of transmission attained in this series of messages was 37|- words per minute. The entire series consisted of messages transmitted from London to Liverpool, on a pair of double needle instruments, at different times of the day, and were carefully tabulated. In the series, several messages were included, the transmission of which was excep- tionally slow, owing either to the difficult nature of the communi- cations, consisting of long words in private cipher, or of the names 63 THE ELECTRIC TELEGRAPH. of foreign towns, or, in fine, from the inaccuracy or slowness of the transmitting clerk in London. It would seem, therefore, that this series of messages includes fair conditions for an average result. It would, therefore, appear that the needle instruments worked by the magneto-electric current used by this company are, ceteris paribus, susceptible of greater celerity of transmission than the instruments in which the needles are affected by the common voltaic current, in the ratio of about 27 to 21, or 9 to 7. One of the causes which has been assigned to this increased efficiency, is the fact that the needles of the magnetic instruments have a dead beat, while those of the voltaic instruments, in strik- ing the stops, have a recoil, and vibrate two or three times before they come to rest. Whether this be the real cause of the differ- ence, further experience must prove, but it is difficult to imagine that it can be due to any cause independent of the instruments, seeing the large number of messages from which the average has been computed. Fig. 87. BAIN'S ELECTRO-CHEMICAL TELEGRAPH. THE ELECTRIC TELEGRAPH. CHAPTER XI. 230. Illustration of the efficiency of the needle instruments. 231. Rate of transmission with the French state telegraphs. 232. With the French railway telegraphs. 233. With the Morse telegraph. 234. Discrepancy of reports. 235. Causes of its celerity. 236. Rate with Bain's telegraph. 237. Transmission of music. 238. Rate of transmission with House's telegraph. 239. Distance sometimes affects celerity. 240. Examples of distant transmissions in U. S. 241. Advantages of uniform organisation. 242. Uses of the electric tele- graph. 243. Subject of dispatches. 244. Effect of the tariff. 245. Uses of the telegraph in railway business. 246. Portable railway telegraph. 247. Practical uses on railways. 248. Its econo- mical advantages. 230. Mr. Walker, writing in 1850, gives the following illustra- tion of the efficiency which has been attained in the working of the needle system, and in the management generally of the telegraphic business : " The rate at which newspaper dispatches are transmitted from Dover to London, is a good illustration of the perfect state to which the needle telegraph has attained, and of the apt manipu- lation of the officers in charge. The mail, which leaves Paris LABORER'S MUSEUM OF SCIBITCE. F 65 No. 47. THE ELECTRIC TELEGRAPH. about mid-day, conveys to England dispatches containing the latest news, which are intended to appear in the whole impression of the morning paper. To this end, it is intended that a copy be delivered to the editor in London about three o'clock in the morn- ing. The dispatches are given in charge to us at Dover soon after the arrival of the boat, which of course depends on the wind and the weather. The officer on duty at Dover, having first hastily glanced through the manuscript to see that all is clear to him and legible, calls 'London' and commences the transmission. The nature of these dispatches may be daily seen by reference to 'The Times.' The miscellaneous character of the intelligence therein contained, and the continual fresh names of persons and places, make them a fair sample for illustrating the capabilities of the electric telegraph as it now is. The clerk, who is all alone, placing the paper before him in a good light, and seated at the instrument, delivers the dispatch, letter by letter, and word by word, to his correspondent in London ; and although the eye is transferred rapidly from the manuscript copy to the telegraph instrument, and both hands are occupied at the latter, he very rarely has cause to pause in his progress, and as rarely also does he commit an error. And, on account of the extremely limited time within which the whole operation must be compressed, he is not able, like the printer, to correct his copy. " At London there are two clerks on duty, one to read the sig- nals as they come, and the other to write. They have previously arranged their books and papers : and, as soon as the signal for preparation is given, the writer sits before his manifold book, and the reader gives him distinctly word for word as it arrives ; mean- while, a messenger has been dispatched for a cab, which now waits in readiness. When the dispatch is completed, the clerk who has received it reads through the manuscript of the other, in order to see thai he has not misunderstood him in any word. The hours and minutes of commencing and ending are noted, and the copy being signed is sent under official seal to its destination, the manifold fac- simile being retained as our office copy, to authenticate verbatim what we have delivered. This copy and the original meet together at the chief telegraph office at Tunbridge, early in the day, and are compared. When the work is over, and the dispatches have reached their destination, the clerks count over the number of words and the number of minutes, and find the rate per minute." 231. The signals adopted to express the letters in the French State telegraph being each made by a single motion of the arms, they necessarily are produced with greater celerity than the multi- plied deflexions of the needle-instruments. Like the double needle- instrument, the French telegraph is composed in fact of two CELERITY OF MORSELS TELEGRAPH. completely independent telegraphic instruments, with, two inde- pendent conducting wires, and its celerity of transmission is due to their combined powers. It is stated by the directors of the administration that the average transmitting powers of these telegraphs is nearly 200 letters or signs per minute. 232. The alphabetical telegraphs, of which the French railway telegraph may be taken as an example, are much slower in their rate of transmission. M. Breguet, who has constructed those worked in France, and superintended and directed their operation, says, that their average rate of transmission, when fairly worked, is about 40 letters per minute. 233. The writing and printing telegraphs are independent of a receiving agent, the receiving apparatus in all these being automatic. All these instruments have an advantage over the English and French telegraphs, inasmuch as they employ only one conducting wire, and those who print the dispatch in the common letter-press characters, have the further advantage of being wholly independent of the skill of any agent to interpret or decipher them. The celerity of transmission attainable with the Morse telegraph, which of" all the forms of telegraphic apparatus hitherto invented is the most extensively used,, is very considerable, but varies perhaps still more than the needle-instruments, with the skill of the telegraphist. In this instrument, it will be remembered that the transmitting agent plays upon a key-commutator, the letters being severally expressed by repeated touches of the key succeeding each other, after longer or shorter intervals. At the station receiving the dispatch, the armature of the electro-magnet moves simultaneously with the transmitting key, and at each of its motions towards the magnet, it produces a distinctly audible click. The receiving agent acquires by practice such expertness and quickness of ear, that by listening to this clicking he is able to interpret the dispatch, and to write it down or dictate it to a clerk without using the apparatus for impressing it upon the paper ribbon. Different telegraphists acquire this power of oral interpretation of the dispatches with different degrees of facility and precision ; but all are more or less masters of it. So much so, that in most cases on the American lines, it is by the clicking of the magnet that the messages are taken down, being afterwards corrected, if necessary, by comparison with the indented paper ribbon. The telegraphist is placed at a table, upon which the instrument stands, having before him the paper upon which the message is to be written, and at his left a provision of blaoklead pencils ready v 2 67 THE ELECTRIC TELEGRAPH. cut and pointed, usually half a dozen. When the transmission of the message commences, the electro-magnet dictates it to him, letter by letter, at the same time indenting it upon the paper ribbon. He writes it down, and, in general, it is delivered by the magnet as fast as he can write it, availing himself of all such abbreviations as are intelligible to those who may have to read it. As the points of the pencils are successively worn he lays them on the table at his right hand. A person engaged exclu- sively in that process, visits his table from time to time, repoints the pencils lying on his right, and replaces them on his left. This person passes round the telegraph office, from table to table, keep- ing up a constant supply of properly pointed pencils at the hand of each telegraphist. The most expert telegraphists are able to take down the mes- sages in this manner by ear, without any reference to the ribbon, and so correctly that there is no need of subsequent verification. When the message is concluded, the sheet on which it is written is handed to another clerk, who is provided with a stock of envelopes, in one of which he encloses it ; and, writing the address upon it, delivers it to a messenger, who forwards it to the party to whom it is addressed. Meanwhile the paper ribbon, on which the message has been indented in the telegraph ciphers, is cut off, folded up, and preserved for reference. It is only, however, the most expert class of telegraphists that can operate in this way. Others, less able, are always obliged to verify and correct what they have taken down, by comparison with the indented ribbon, after the message has been concluded ; while others less able still, cannot trust themselves to take down by ear, and sit before the ribbon as it is discharged from the roller, writing out the message from it by eye. The salaries allowed to different agents vary according to the skill they attain in these operations. One who acquires the power of taking down rapidly and correctly by ear will receive twice the amount allowed to him who can only take down by eye, the latter being always much slower than the former. It often happens that the power of interpreting easily and correctly by ear is very important, as in the case in which the mechanism of the instrument for moving and indenting the paper may have been accidentally deranged and disabled, or in which the office may be deficient in its supply of paper ribbon. By the oral method of reception the entire receiving apparatus, except the electro-magnet and its armature, is dispensed with. If a mistake is committed by the transmitting agent, in conse- quence of which a word or phrase is unintelligible, the receiving agent intercepts the current, and signifies that the word is to CELERITY OF MORSELS TELEGRAPH. be repeated, and at the same time tears off the erroneous part of the ribbon. This, however, is a circumstance of rare occurrence. When a very long dispatch is transmitted, and arrives with greater celerity than that with which an agent can transcribe it, the ribbon may be divided, and two agents put to work at once at its transcription. The reports of congress and public meetings transmitted to the journals, afford examples of this. These reports may be, by one operation, transmitted to all the towns upon the same telegraphic line. In some cases long dispatches, such as those addressed to the journals, are expedited by two or more instruments on different wires. The dispatch is, in this case, divided into two or more parts, marked 1, 2, 3, or A, B, c, &c., and these parts are simul- taneously transmitted to theif destination, being reunited there after their arrival. This expedient, however, can only be resorted to where there are two or more line wires, which is a rare case in the United States. 234. If the celerity of transmission of the Morse instrument be compared with that of the English and French telegraphs, it must not be forgotten that the latter require two wires, while the former requires but one. In the transmission and reception of a dispatch both, however, employ the same number of agents. There is great discrepancy in the reported estimates of the celerity of transmission of the Morse telegraphs, owing probably to the varying skill of the telegraphists on whose performance such estimates have been based. According to Mr. Turnbull, the average celerity of transmission of this telegraph is from 135 to 150 letters per minute. In a report made by Mr. O'Reilly, the director of one of the most extensive of the New York Companies, it is stated that the average rate of transmission is from 20 to 23 words per minute. Since it is generally estimated that the average length of tele- graphic words is five letters and a half, this would amount to 110 to 127 letters per minute. Mr. O'Reilly adds, however, that a " higher rate of transmission could be obtained, but as nearly all operators copy from their instruments, and reduce the messages to ordinary writing as they arrive, the rate of 20 to 23 words is considered rapid enough, as an expert operator can indent his Morse characters faster than most men can write the words they express with a pen or pencil." We may perhaps take 150 letters as a fair estimate of the rate of transmission, and it follows therefore that this telegraph is more rapid than the double needle-telegraph in the ratio of about 3 to 2, and since the latter employs two wires with their accessories, while the former employs only one, it follows that the transmitting THE ELECTRIC TELEGRAPH. power of each wire with the Morse telegraph is three times as great as with the double needle instrument. 235. The causes of this greater celerity are twofold : first, the greater celerity with which the ciphers are impressed upon the ribbon of paper, compared with that with which the visible signals are exhibited and succeed each other in the English and French telegraphs ; and secondly, the removal of those delays of trans- mission which arise from the want of attention or quickness of eye on the part of the agent receiving the dispatch, rendering it necessary to repeat words which have been missed or misunderstood. In the American offices of the Morse lines, it is stated in the published reports that " there are a number of attendants, each one of whom has his respective department ; they are divided into ' copyists, book-keepers, battery-keepers, messengers, line inspec- tors, and repairers.' The usual charge of transmission is 25 cts., equal to a shilling, for ten words exclusive of the address and the signature sent 100 miles : the messages vary in price from 10 cts., or 5d., to 100 dols., or 20?. The amount of business which a well-conducted office can perform, and the net proceeds arising therefrom, may well excite surprise ; a single office in that country, with two wires, one 500, the other 200 miles in length, after spending three hours in the transmission of public news, tele- graphed, in a single day, 450 private messages, averaging 25 words each, besides the address and signature, sixty of which were sent in rotation, without a word of repetition." 236. All that has been said above relating to Morse's telegraph may mutatis mutandis be applied to other telegraphic instruments, which write in cipher the dispatches by self-acting machinery, such as those described in 191, 192, and 193. "When dispatches are transmitted by means of a key- commu- tator, with Bain's telegraph, the operation being precisely similar to that of Morse, the celerity of transmission by operators of equal skill ought to be the same. Nevertheless, as these instruments of Bain's, with some modifications, are at present used on certain lines by the Electric Telegraph Company, Mr. Foudrinier has, at my request, caused a series of messages to be timed, of which the following is the summary of the results : 63 Messages. Total number of words in the addresses . 456 ,, messages . . 991 Total number of words transmitted . 1447 Total time of transmission 4454 .seconds. Average number of words transmitted per minute . -19s It appears, therefore, that as this telegraph is worked in 70 CELERITY OP BAIN ? S TELEGRAPH. England, its rate of transmission is slower than the double needle telegraph. The advantage which attends its use is that it writes the dispatch in cipher, which is preserved in the telegraphic office, so that the labour of a clerk to copy the dispatch for reference is saved. It would follow from the comparison of this result with the reports of the American telegraph, that the operators with Bain's system in England are not as expert as those of Morse's in America. But when the method of transmitting by a pre- viously-prepared perforated ribbon, described in 194, is resorted to, the apparatus is rendered absolutely automatic, no agency being required either in the transmission or reception, save that required for the perforation of the transmitting ribbon, and the interpretation and transcription of the dispatch delivered in the telegraphic cipher. Whatever may be thought of the practical difficulties which at present obstruct the application of this method of rapid telegraphic transmission, we cannot help thinking that it has before it a great future, and that when, like the steam-engine as improved by Watt, and the power-loom, it shall have had time to attain a greater degree of practical perfection, and to surmount prejudice and the opposing influence of counter-interests, it may be the means of transferring, to the telegraph, a large part of that business now done by the post-office. 237. It is an amusing fact, that music has actually been trans- mitted in this way by means of its rhythm. The following is related by an eye-witness of the experiment at New York : " We were in the Hanover Street office when there was a pause in business operations. Mr. W. Porter, of the office at Boston, asked what tune we would have. We replied ' Yankee Doodle,' and to our surprise he immediately complied with our request. The instrument commenced drumming the notes of the tune as perfectly and distinctly as a skilful drummer could have made them at the head of a regiment ; and many will be astonished to hear that ' Yankee Doodle ' can travel by lightning. We then asked for ' Hail, Columbia ! ' when the notes of that national air were distinctly beat off. We then asked for l Auld lang syne,' which was given, and ' Old Dan Tucker,' when Mr. Porter also sent that tune, and, if possible, in a more perfect manner than the others. So perfectly and distinctly were the sounds of the tunes transmitted, that good instrumental performers could have had no difficulty in keeping time with the instruments at this end of the wires." * That a pianist in London should execute a fantasia at Paris, * Chambers' s Papers for the People, vol. ix. No. 71. 71 THE ELECTRIC TELEGRAPH. Brussels, Berlin, and Vienna, at the same moment and with the same spirit, expression, and precision as if the instruments, at these distant places, were under his fingers, is not only within the limits of practicability, but really presents no other difficulty than may arise from the expense of the performances. From what has been just stated, it is clear that the time of music has been already transmitted, and the production of the sounds does not offer any more difficulty than the printing of the letters of a dispatch. 238. A great celerity of transmission is claimed for the printing telegraph of House, so great, that if the claim be well founded, it is a matter of surprise that it has not superseded the Morse tele- graph in the United States, where competition is so sharp and action so free. According to Mr. Turnbull, who ought to be con- sidered an impartial assessor, at least between inventors who are both American, the ordinary rate of transmission of the improved House instrument is from 30 to 35 words, printed in full, per minute, which would be from 165 to 200 letters. He adds, that business-messages are sent at the rate of 200 to 250 letters per minute, and that in one case 365 letters, transmitted from New York, have been printed at Utica, distant 240 miles, in one minute. In a written estimate supplied by the directors of the House lines to Mr. Jones,* it is also stated that, accidents apart, the average number of words transmitted on a single wire per minute and printed in full by the telegraph at their place of destination, is from thirty to thirty-five ; but when as in newspapers abbrevia- tions are allowed, the rate is fifty. It is stated for example that the proceedings of the democratic state convention in the autumn of 1850, containing 7000 words, were transmitted from Syracuse to Buffalo in two hours and ten minutes, being at the rate of 54 words per minute. It is evident that in this telegraph, like others, much depends on the ability of the telegraphist, for it is stated that one telegraphist on the line has transmitted 365 letters in a minute, being at the rate of six per second. When it is considered that this telegraph delivers its messages printed in the ordinary Roman characters, while all the others in practical operation deliver them either in visible signs or written ciphers, which must be interpreted and taken down in ordinary writing before they can serve any useful purpose, the vast superiority of this system of House must be conspicuously manifest, supposing of course that the reports and estimates above produced are verified by the actual performance of the instrument. * Jones. Elec. Tel., New York, 1852, p. 112. CELERITY OF HOUSE'S TELEGRAPH. 239. Although the distance to which the dispatch has to be sent cannot be said directly to affect the celerity of transmission, there are circumstances nevertheless which in practice render the transmission to great, slower than to lesser distances. In Europe, for example, stations separated by great distances, are generally in different countries, and the telegraphic line which connects them often passes through several different states in which different telegraphic systems are used, and where it is not practi- cable to put the wires proceeding from one direction in immediate connection with those which proceed in another. In such cases the messages which arrive must be taken down and retransmitted in the direction in which they are intended to be forwarded, and on this account alone, the time of transmission is augmented, at least in the ratio of the number of such repetitions which are necessary. But besides this, it rarely happens that a message on arriving at such intermediate station can be at once for- warded. It must wait its turn unless the wires happen to be unoccupied. And even though it may be practicable to establish a direct communication between two distant stations by putting the wires in immediate connection, more or less delay must necessarily take place. The telegraphist who transmits, must first send a message along the line to all the intermediate stations to require the wires to be united for direct communication. At these intermediate stations, the wires may be employed, and the message must wait until they are free. Thus, although it be true that so far as the electric fluid and the ^apparatus by which it is transmitted are concerned, they are capable of sending a message from pole to pole in an inappreciable interval, yet the machinery of telegraphy as practically constructed presents causes of delay which prevent in many cases this vast oelerity from being called into action. Until very recently, a message transmitted from Milan to Paris, being necessarily sent round by Trieste, Vienna, Berlin, and Brussels, was more than twenty-four hours in reaching its destination. Besides these causes of delay, there are, however, others. It has been stated that the intensity of the current is diminished, ceteris paribus, as the distance is augmented. When transmission therefore to great distances is required, various expedients, at intermediate stations, such as relay batteries or relay magnets, or both, are required, and notice must be given to apply these even when they are provided. The chances of interruption by reason of defective insulation or accidents to the wires, are also increased in proportion to the distance. 73 THE ELECTRIC TELEGRAPH. 240. As may be naturally expected, tlie most frequent examples of direct telegraphic communication to great distances are supplied by the United States. On the lines of the O'Reilly Company of New York,* messages are daily transmitted without any intermediate repetition to a distance of 1100 miles, that is from New York to Louisville in Kentucky, "To do this, it is found necessary to place two batteries in the circuit at a distance of 400 miles apart, for the purpose of renewing the electric current, part of which escapes from defective insula- tion and atmospheric causes. There is no doubt but that, in a more advanced stage of telegraphing which may be but a short time hence New Orleans and New York will be placed in instantaneous communication with each other. To enable this to take place, requires, in the first place, a line substantially built and thoroughly insulated. It may be remarked, that it is but two years since, when to telegraph 300 miles on a single or unbroken circuit, was considered a feat ; now, from improvements made since then in telegraphs, we can send over 1100 miles easier than we could 300 at that time. In our Cincinnati office, two years ago, and until very lately, they used a separate battery for each line. From a series of experiments made, one single battery, of no greater strength than those formerly used, now works eight distinct and separate lines, with no apparent diminu- tion of strength, and at a great saving of expense to the office." t A report of the directors of the New York Bain lines states that messages are transmitted by them, without being rewritten, from New York to Buffalo, a distance of 500 miles. This is done without any intermediate relay batteries or magnets. The directors of the Morse lines at New York report that their telegraph messages have in some cases been actually transmitted without intermediate repetition to a distance of 1500 miles. 241 . The promptitude with which dispatches are expedited, and the celerity with which they are transmitted, will be greatly promoted in all cases by an uniform system and organisation being established upon the lines over which they are transmitted. No greater cause of delay can exist than that which arises from diversity of telegraphic instruments and language. Much * The American Telegraph Companies are subject to such constant changes, that it may be necessary to state here, once for all, that the names and denominations to which we refer are those which were current in 1853-4, but which may be changed before these sheets come into the hands of the reader. t Report of Mr. O'Reilly. Jones's El. Tel., p. 101. 74 CELERITY OF AMERICAN LINES. inconvenience, expense, and delay also arise even in cases where similar instruments and ciphers are used, from a want of uniformity in the various parts of the apparatus, and in the systems of abridgments which are adopted in the language. Where the instruments and the parts of apparatus have been constructed of varying patterns and sizes, they cannot be readily replaced in cases of wearing out or accidental fracture. By the adoption of one uniform size and pattern, depots of all the parts may be provided, from which any station which may be stopped by an accident can be immediately supplied with the part or parts which require to be replaced. Another advantage incidental to such uniformity is greater economy in the maintenance of the apparatus and lines. Impressed with these considerations, a large majority of the American telegraph companies have formed themselves into a con- federation, which meets annually at Washington, and which is permanently represented there by a permanent commiftee and secretary. This body has published reports containing many important and interesting statistical facts, and has adopted measures with a view to the establishment of a central depot for the supply of all articles necessary for the maintenance of the lines and stations, of good quality and at fair prices. The secretary of the convention, Mr. J. P. Shaffher, has commenced the publication of a monthly periodical .devoted to subjects directly and indirectly connected with electric telegraphs ; and as not less than nine-tenths of all the American lines, as well as those of contiguous states, are worked with Morse's instrument, it is proposed to reduce it as speedily as pos- sible to one uniform pattern, so that its parts, as well as those of the batteries, may be always ready to be supplied in cases of failure or breakage, the like parts fitting indifferently all instruments and all apparatus. The batteries invariably used by the American telegraphs are those of Grove, each element of which consists of a cup of unglazed earthenware, placed in a glass tumbler of equal height and greater diameter. A zinc cylinder is let down between the glass and the earthenware cup, and a platinum cylinder is let down into the earthenware cup. The space between the cups is then filled with acidulated water, and the earthenware cup is filled with pure nitric acid. Such being the batteries, the articles of consumption in the working of the telegraphs are enumerated as follows by the secretary of the convention: Nitric and sulphuric acids, zinc, quicksilver (for amalgamating the zinc, &c.), skeleton forms for messages, ink, envelopes, pencils, and pens. 75 ELECTRIC TELEGRAPH. From statistical data collected by tlie secretary, it was found that in 1853 the annual consumption and cost of these materials was as follows : Quantities. Cost. Nitric acid .... Sulphuric acid Zinc cylinders Mercury . . Forms for messages Envelopes . . . + Pens . . . ;.' 1996801k 50000 Ib. 16500 Ib. 3000 Ib. 10,000000 6,000000 576000 50000 1105 500 400 600 5000 2680 720 500 These returns, including only the results of the lines worked by the Morse instruments, about nine-tenths of the whole, would require to be increased by a ninth to obtain the total consumption. It appears, therefore, that on the lines of the United States, the number of telegraphic messages transmitted in 1853 exceeded ELEVEN MILLIONS! THE TJSES OF THE ELECTKIC TELEGRAPH. 242. To form an estimate of the uses to which the electric telegraph subserves, it would be necessary to obtain a report of the subjects of the messages classified, with the relative number of each class, which are transmitted from and received by the chief telegraphic stations. Although we have not been able to procure to any great extent such data, some notion may be collected as to the way in which this new social, commercial, and political agent is employed, from such scattered statements and notices as we have been enabled to collect from various sources. It appears that the prevailing subjects of the dispatches vary according to the station from or to which they are sent. Thus, as might naturally be expected, in large commercial marts, such as Liverpool and Glasgow, they are chiefly engrossed by messages of mercantile firms and business. Their prevailing subjects also vary much with the season of the year. Thus, in summer, the messages of tradesmen are greatly multiplied in con- sequence of the number transmitted by dealers in perishable articles, such as fish, fruit, &c., which must be supplied in regulated quantities with the greatest promptitude. We have obtained from the manager of the English and Irish magnetic telegraph company, the following classification of 76 USES OF THE ELECTRIC TELEGRAPH. nearly 5000 dispatches which passed through the Liverpool office in the early part of the present year, 1854. General merchants Stock and share transactions Ship insurers, brokers, &c. Banking messages Corn dealers . Betting .... Personal and domestic . General brokers Tradesmen . . . Cotton brokers, &c. Law .... Political 1954 1441 339 315 272 233 201 117 50 34 31 4993 243. Mr. Walker gives the following list of the subjects of dispatches sent through the office of the Electric Telegraph Company, as a specimen of the uses which the public make of this mode of communication. Accidents Customs Markets Post-horses, &c. Announcements Deaths Medical aid Reporters Appointments ! Departures Meteorology Remittances Arrivals Dispatches Missing trains Respite Arrests Elections Murders Robberies Bankers Elopements News Royal movements Beds Expresses Nurses Sentences Bills Funds and Shares j Orders Shipping news Births Government Passengers Ship-stores Commotions Health Payments Turf Counsel Hotels Police Witnesses Couriers Judgments j Political Wrecks Corps Lost luggage ' It is obvious that the uses, whether personal or commercial, of the telegraph, are restricted by the tariff, and by the necessity of disclosing the contents of the dispatches to the telegraph agents. In England, the latter obstacle may in some cases be surmounted by the use of a cipher. The cipher must, however, always consist of a transposition of the letters, since the telegraphic signs only express letters, and besides this, it can never be used on sudden emergencies, inasmuch as it supposes a previous concert between the corresponding parties. 244. The obstacle to the extension of the uses of the telegraph, created by the tariff, has been of late greatly lessened by the considerable reduction of the prices of transmission, and it may be hoped that ere long the companies and the public will discover that the interest of the one and the convenience of the other will 77 THE ELECTRIC TELEGRAPH. be best promoted by a still further reduction of price, and a still larger use of this mode of intercommunication. It is probable and desirable that something approaching to the uniform postage system may eventually be realised in the telegraph. Already a certain step towards such a system has been made, since for a fixed sum messages of a prescribed length can be transmitted to all distances exceeding a certain limit. In the absence of exact statistical reports of telegraphic business, it may not be uninteresting to give some examples of the uses of this mode of communication. 245. In the management of railway business in all countries, but more especially upon our own ever crowded and over- worked lines, the telegraph has become an indispensable accessory, without which this mode of locomotion would be deprived not only of its efficiency but its safety. Consequently the railways in most countries have been provided with lines of telegraph expressly and exclusively for their own use, independently of those which are appropriated to the public service ; and on the continent such telegraphs are usually alphabetic, that is, such as convey their messages by pointers, which are successively directed to the letters of the words, so that any of the railway officials who can read, may be able to interpret a message which arrives, or to transmit one to a distant station. x To illustrate the vast utility of the telegraph to the railway, Mr. "Walker states that on the lines of the South Eastern Company, in the space of three months, upwards of 4000 messages have been occasionally transmitted, being at the average rate of nearly 50 per day. He gives the following as a rough classification of their subjects Messages. 1. Concerning ordinary trains. ' . 1468 Special trains . Carriages, trucks, goods, sheets, &e Company's servants . Engines . Miscellaneous matters Messages forwarded to other stations 429 795 607 150 162 499 Total 4110 246. It has been already stated that portable telegraphs are pro- vided in some parts of the continent, and in France in particular, with which the conductors are provided. Such telegraphs have also been contrived in this country, but we are not aware of their practical adoption. By these the conductor of a train can, whenever the train is stopped between stations, whether from accident or other 78 ' . USES OF THE TELEGRAPH TO RAILWAYS. cause, give immediate notice to the preceding and succeeding sta- tions, so as to prevent a collision by a following train overtaking that which is accidentally stopped, or if necessary he can call for an engine to carry on the train, or any other aid that may be required. 247. Notices of the passing, starting, and arrival of trains are however transmitted from station to station, quite independent of any accidents that may arise, so that all the station-masters, so far as relates to the movement upon the line, are endowed with a sort of omnipresence ; so conscious are they of the possession of this power and its value, that their language is that of persons who actually see what is going on at vast distances from them. Thus, as Mr. Walker observes, they are in the common habit of saying " I just saw the train pass such or such a station," fifty miles distant perhaps, when in reality all he saw was the deflec- tion of the needle of their telegraph. " If trains are late, the cause is known ; if they are in distress, help is soon at hand : if they are heavy, and progress but slowly, they ask and have more locomotive power either sent to them or prepared against their arrival ; if there is anything unusual on the line they are forewarned of it, and so forearmed ; if overdue, the old plan of sending an engine to look after them has become obsolete a few deflections of the needle obtain all the information that is required." * The utility of special trains is well known. News of the utmost importance, or a government courier bearing . dispatches of the greatest urgency arrives at one of our ports and demands a train instantly to convey him to London. Now in such cases it does not often happen that a disposable engine is found at the station where the demand is presented ; but the telegraph sends a dis- patch along the line, calling one from the nearest station at which one can be found, and when the engine has been obtained the special cannot start with safety unless the line is cleared for it. The telegraph again interposes its aid, and sends a notice along the line of the moment of starting, from which, combined with the known speed of the train, the exact moment when it will pass every station upon the line is known, and of course the line is cleared for it, and all danger of collision removed. How frequent are the occasions for appealing to the telegraph for this aid without which special trains would not only be less rapid, but infinitely less safe, as well for themselves as others, may be seen by^reference to the analysis of dispatches we have given above, from which it appears that in three months, upon the South- * Walker, p. 84. 79 THE ELECTRIC TELEGRAPH. Eastern lines, there were not less than 429 messages respecting special trains, that is at the rate of about five per day. 248. In the general management of the traffic upon an active line of railway, an incalculable amount of capital and current expenditure is saved by the telegraph. "Without it rolling stock would require to be provided in much greater quantity, and a far greater unprofitable wear and tear by useless trips, of what in railway language are called "empties," would take place. By the telegraph, as we have stated, each station-master is ubiquitous so far as the line is concerned. He knows where carriages, waggons, trucks, sheets, and engines are to be found, and how many of them, and he calls by the telegraph so many, and no more than he wants, and at the time he wants them, from the nearest or most convenient station where they are to be obtained. Before the establishment of the telegraph, some of these objects were imperfectly attained by means of pilot engines, that is engines taking no vehicle, which habitually run along the line to carry messages from station to station. As an evidence of the immense saving effected by the telegraph in the practical working of rail- ways, Mr. Walker states, that the cost of maintaining and working a single one of those pilot engines, (all of which have been super- seded by the telegraph,) amounted to a greater sum than is now required to defray the expense of the entire staff of telegraph clerks, and the mechanics and labourers employed in cleaning and repairing the instruments and maintaining the integrity of the line wires. Fig. 89 HOUSE'S TELEGKAPH. THE ELECTRIC TELEGRAPH. CHAPTER XII. 249. Prevention of accidents. 250. Its uses in the detection of crime. 251. Personal and domestic messages. 252. Electric news-rooms. 253. Telegraph extensively used in the United States. 254. Much used for commerce. 255. Sums paid for telegraphic despatches by mercantile firms. 256. Extensively used by American newspapers. 257. Illustration of the utility for political purposes. 258. Illustra- tions of its domestic and general use. 259. Secrecy of despatches not generally sought for. 260. Verbal ciphers of mercantile firms. 261. Ciphers for newspaper reports. 262. Association of New York journals. 263. Spirited enterprise of New York "Herald." 264. Use of electric telegraph in determining longitudes. 265. In pro- ducing horological uniformity. 249. AMONG the serious railway accidents which, might have been, or actually were prevented by the telegraph, the following have been mentioned : In a storm, the wind blew a first-class railway carriage, which LAKDNER'S MUSEUM OF SCIENCE. a 81 No. 49. THE ELECTRIC TELEGRAPH. stood in an open shed at a second-class station, and putting it in motion upon a very level line, sent it flying with accele- rated speed to the terminal station. No telegraph at that time existed to warn either the intermediate or terminal stations of the event and the approaching danger. The vehicle was actually blown over twenty-one lines of railway, but the trip it thus took occurring fortunately at an hour of the night when little business was going on, it came to rest without any cala- mitous result. Mr. "Walker mentions the following : " On New Tear's Day, 1850, a catastrophe, which it is fearful to contemplate, was averted by the aid of the telegraph. A collision had occurred to an empty train at Gravesend ; and the driver having leaped from his engine, the latter started alone at full speed to London. Notice was immediately given by telegraph to London and other stations ; and while the line was kept clear, an engine and other arrangements were prepared as a buttress to receive the runaway. The superintendent of the railway also started down the line on an engine ; and on passing the runaway, he reversed his engine and had it transferred at the next crossing to the up- line, so as to be in the rear of the fugitive ; he then started in chase, and on overtaking the other, he ran into it at speed, and the driver of his engine took possession of the fugitive, and all danger was at an end. Twelve stations were passed in safety : it passed "Woolwich at fifteen miles an hour : it was within a couple of miles of London before it was arrested. Had its approach been unknown, the mere money value of the damage it would have caused might have equalled the cost of the whole line of telegraphs. They have thus paid, or in a large part paid, for their erection. " As a contrast to this, an engine, some months previously, started from New Cross toward London. The Brighton Com- pany have no telegraphs ; and its approach could not be made known. Providentially, the arrival platform was clear; it ran in, carrying the fixed buffer before it, and knocked down, with frightful violence, the wall of the parcels office." 250. Among the general uses of the telegraph to the public, many examples of the detection of crime are mentioned. It is generally known that the notorious Tawell, after the commission of the murder, started for London from Slough, by the Great "Western Railway. Notice of the crime, and a description of his person, however, flew with the speed of light along the wires and arrived at Paddington so much earlier than the mur- derer himself, that upon his arrival he was recognised, tracked 82 USES OF THE TELEGKAPH. from place to place, finally apprehended, tried, convicted, and executed. One night at ten o'clock, the chief cashier of the bank received a notice from Liverpool, by electric telegraph, to stop certain notes. The next morning the descriptions were placed upon a card and given to the proper officer, to watch that no person exchanged them for gold. Within ten minutes they were pre- sented at the counter by an apparent foreigner, who pretended not to speak a word of English. A clerk in the office who spoke German interrogated him, when he declared that he had received them on the Exchange at Antwerp six weeks before. Upon reference to the books, however, it appeared that the notes had only been issued from the bank about fourteen days, and therefore he was at once detected as the utterer of a falsehood. The terrible Forrester was sent for, who forthwith locked him up, and the notes were detained. A letter was at once written to Liverpool, and the real owner of the notes came up to town on Monday morning. He stated that he was about to sail for America, and that whilst at an hotel he had exhibited the notes. The person in custody advised him to stow the valuables in his portmanteau, as Liverpool was a very dangerous place for a man to walk about with so much money in his pocket. The owner of the property had no sooner left the house than his adviser broke open the portmanteau and stole the property. The thief was taken to the . Mansion-House, and could not make any defence. The sessions were then going on at the Old Bailey. Though no one who attends that court can doubt that impartial justice and leniency are adminis- tered to the prisoners, yet there is no one who does not marvel at the truly railway-speed with which the trials are conducted. By a little after ten the next morning such was the speed not only was a true bill found, but the trial by petty-jury was concluded, and the thief sentenced to expiate his offence by ten years' exile from his native country. I take the following illustration of this from a recent article on the subject which appeared in the " Quarterly Review." The following is extracted from the telegraph book preserved at the Paddington station : "Paddington, 10.20A.M. ( Mail train just started. It contains three thieves, named Sparrow, Burrell, and Spurgeon, in the first compartment of the fourth first-class carriage.' "Slough, 10.48A.M. * Mail train arrived. The officers have cautioned the three thieves' " Paddington, 10.50 A.M. Special train just left. It contained two thieves : one named Oliver Martin, who is dressed in black, crape on his hat ; the other named Fiddler Dick, in black trousers G 2 83 THE ELECTRIC TELE8RAPH. and light blouse. Both in the third compartment of the first second-class carriage." " Slough, 11.16 A.M. l Special train arrived. Officers have taken the two thieves into custody, a lady having lost her bag, containing a purse with two sovereigns and some silver in it; one of the sovereigns was sworn to by the lady as having been her property. It was found in Fiddler Dick's watch-fob.' " It appears that, on the arrival of the train, a policeman opened the door of the * third compartment of the first second-class carriage,' and asked the passengers if they had missed anything ? A search in pockets and bags accordingly ensued, until one lady called out that her purse was gone. ' Fiddler Dick, you are wanted,' was the immediate demand of the police-officer beckoning to the culprit, who came out of the carriage thunderstruck at the discovery, and gave himself up, together with the booty, with the air of a completely beaten man. The effect of the capture so cleverly brought about is thus spoken of in the telegraph book : "Slough, 11.51 A.M. 'Several of the suspected persons who came by the various down- trains are lurking about Slough, uttering bitter invectives against the telegraph. Not one of those cautioned has ventured to proceed to the Montem.' " Ever after this the light-fingered gentry avoided the railway and the too intelligent companion that ran beside it, and betook themselves again to the road a retrograde step, to which on all great public occasions they continue to adhere." * 251. One of the consequences of the high price of transmission is that personal and domestic messages are most generally confined to cases of urgency, and often of distress, painful or ludicrous, as the case may be. Persons in easy circumstances, it is true, often resort to the telegraph to gratify a caprice or to obtain some object of gratification for which they are impatient. The mixture of subjects which the agents in rapid succession read from the needles, is most curious. " We have," says Mr. Walker, "ordered a turbot, and also a coffin ; a dinner, and a physician ; a monthly nurse, and a shooting-jacket ; a special engine, and a chain-cable ; an officer's uniform, and some Wenham-lake ice ; a clergyman, and a counsellor's wig ; a royal standard, and a hamper of wine ; and so on. Passing over the black leather bag which some one every day appears to leave in some train, passengers have recovered luggage of most miscellaneous character by means of the telegraph. * Quarterly Review, No. CLXXXIX., p. 129. USES OF THE TELEGRAPH. In the trains have been left a pair of spectacles, and a pig ; an umbrella, and Lay arc? s Nineveh ; a purse, and a barrel of oysters ; a great-coat, and a baby ; and boxes and trunks, et id genus omne, without number." 252. Independently of the direct use made of the electric telegraph by the general public, for the transmission of private despatches, the several companies have established, in various principal places, news rooms, where intelligence is from hour to hour posted, as it arrives from all parts of the world. The Electric Telegraph Company, soon after its establishment, opened subscription news rooms in the chief towns of England, especially those of the northern counties, in which intelligence of every description which could interest the general public was posted from hour to hour during the day, immediately on its transmission from London. These establishments did not, however, receive the necessary public support, and with one or two exceptions they have been discontinued. There is, however, in the Lothbury establishment, besides the private message department, a general intelligence office, in which the news published in the morning journals is condensed and transmitted to the exchanges of Liverpool, Bristol, Manchester, Glasgow, and other chief provincial centres of business. On the evenings of Fridays, the London news is collected, con- densed, and transmitted to the offices of upwards of 120 provincial Saturday papers, which thus receive during the night before their publication the most recent intelligence of every sort received by telegraph from all parts of Europe besides the current news of London to the latest moment. An example of the extra- ordinary efficiency of this department is given in the case of one of the Glasgow Saturday journals, which often receives as much as three columns of the debates, transmitted while the Houses are still sitting. A superintendent and four clerks are exclusively engaged in the business of this department, and in the latter days of the week their office presents all the appearances of the editor's room of a widely circulating journal. " At seven in the morning the clerks are to be seen deep in < The Times' and other daily papers, just hot from the press, making extracts and condensing into short paragraphs all the most important news, which are immediately transmitted to the country papers to form second editions. Neither does the work cease here, for no sooner is a second edition published in London than its news, if of more than ordinary interest, is transmitted to the provinces." Arrived at the chief places in direct communication with London "swifter than a rocket could fly the distance, like a rocket it bursts and is 85 THE ELECTRIC TELEGRAPH. again carried by diverging (branch) wires into a dozen neigh- bouring towns " of less magnitude and importance.* Besides this organisation for the general transmission of des- patches from one quarter of the great metropolis to another, there are some curious special arrangements made for the satisfaction of the wants of particular classes. Thus a wire is exclusively appro- priated to communications between the Octagon Hall of the Houses of Parliament and the telegraphic station in St. James- street, the centre of the "West-end clubs. This particular wire should be called the " ' whipper-in ' of the House, for it is nothing more than a call-wire for members. The company employ reporters during the sitting of Parliament to make an abstract from the gallery of the business of the two Houses as it proceeds, and this abstract is forwarded at very short intervals to the office in St. James's-street, where it is set up and printed, additions being made to the sheet issued as the MS. comes in. This flying sheet is sent half-hourly to the following clubs and establish- ments : Arthur's ; Carlton ; Oxford and Cambridge ; Brookes's ; Conservative ; United Service ; Athenaeum ; Reform ; Travellers' ; United University; Union; and White's. Hourly to Boodle's Club and Prince's Club ; and half-hourly to the Royal Italian Opera. The shortest possible abstract is of course supplied, just sufficient in fact to enable the after-dinner M.P. so to economise his proceedings as to be able to finish his claret and yet be in time for the ministerial statement, or to count in the division. The following, for instance, is a fac-simile of the printed abstract of the debate on the Address to her Majesty on the declaration of war : THE ELECTRIC TELEGRAPH COMPANY. (INCORPORATED 1846.) HOUSE OP COMMONS, FRIDAY, MARCH Slsr, 1854. TIME. REMARKS. II. 4 4 4 5 5 M. 30 40 30 House made. Private business and Petitions. Mr. Napier brought up report of Dungar- van Election Committee : Maguire duly elected, and attention called to state of law upon the withdrawal of Petitions. Notices. Lord John Russell moving reply to message of Her Majesty. HOUSE OF LORDS. Lord Aberdeen stated, in reply to Lord Roden, that it was intended to appoint a day for solemn prayer for a blessing on Her Majesty's arms by sea and land. Earl of Clarendon moved * Quarterly Review, No. CLXXXIX., p. 138. 86 USES OF THE TELEGRAPH. TIMK. REMARKS. H. M. 6 Stating various transactions and negotia- the address in reply to tions which have taken place with the Queen's message. Russia. Earl of Derby : observa- 6 30 Mr. Layard approved of the sentiments tions. expressed. (7-30). Earl of Aberdeen 7 Still speaking. replied to Lord Derby. 7 30 Compared the language and opinions of (7 ' 45). Earl of Malmes- different Members of the Cabinet, and bury regretted the tone called attention to various articles in taken by the Prime the " Times," which he maintained to Minister. be written with a full knowledge of the (8'20). Earl Granville : contents of the secret and confidential observations. correspondence. Lord Brougham ditto. s Mr. Bright replied to Mr. Layard, adverse Earl Grey ditto. to policy of the Government. (8-50). Earl of Hard- 8 30 Still speaking. wicke wished for a 9 Still speaking. larger Naval Reserve. 9 30 Mr. J. Ball was prepared to support the (8 '55). Marquis of Lans- war, though not agreeing in the reasons downe said it was neces- put forward to justify it. sary to check Russia. 10 The Marquis of Granby expressed his (9 ' 5). Address agreed regret at the language used by certain to, to be presented on members of the Government with re- Monday. spect to the Emperor of Russia, whose LORDS ADJOURNED, 9 ' 25. conduct regarding Turkey he vindicated. Lord Dudley Stuart. 10 30 Still speaking. 11 Lord Palmerston vindicating the policy of the Government. 11 30 Mr. Disraeli supported the address, but severely criticised the conduct of differ- ent Members of the Cabinet. 12 Analysing the secret and confidential cor- respondence to show that a plan for the partition of Turkey was assented to by the English Government in 1844, when the Earl of Aberdeen was Secretary for Foreign Affairs. 12 3C Lord John Russell replying to Mr. Layard, J and the observations of other speakers. 12 40 Colonel Sibthorp : observations. The Address to Her Majesty agreed to ; and on the motion of Lord John Russell, and seconded by Mr. Disraeli, to be presented by the whole House. 1 HOUSE ADJOURNED. Saint James's Street Branch Station, No. 89, at the End of Pall Mall, opposite Saint James's Palace. ST THE ELECTRIC TELEGKAPH. " The wire to the Opera is a still more curious example of the social services the new power is destined to perform. An abstract of the proceedings of Parliament similar to the above, but in writing, is posted during the performance in the Lobby, and Young England has only to lounge out between the acts to know if Disraeli or Lord John Russell is up, and whether he may sit out the piece, or must hasten down to Westminster. The Opera-house even communicates with the Strand-office, so that messages may be sent from thence to all parts of the kingdom. The government wires go from Somerset-house to the Admiralty, and thence to Portsmouth and Plymouth by the South- Western and Great Western Eailways ; and these two establishments will shortly be put in communication, by means of subterranean lines, with the naval establishments at Deptford, Woolwich. Chatham, Sheerness, and with the Cinque Ports of Deal and Dover. They are worked quite independently of the company, and the messages are sent in cipher, the meaning of which is unknown even to the telegraphic clerks employed in- transmitting it. In addition to the wires already spoken of, street branches run from Buckingham Palace and Scotland Yard (the head police-office) to the station at Charing-cross, and thence on to Founder's-Court ; whilst the Post-office, Lloyd's, Capel-court, and the Corn Exchange com- municate directly with the central office." * The Magnetic Telegraph Company have made arrangements by which the correspondents of the press are allowed to forward messages upon an entirely different basis; the charge for intel- ligence so transmitted, amounting to only one-tenth of the charge to the public, the matter being more voluminous, and passing through the wires at a time when they are not otherwise occupied. The company also supplies the press and news-rooms in various parts of the United Kingdom, and especially throughout Ireland, with news by contract ; at the rate of about one half- penny per line of ten words ; and are enabled to do so, by making manifold copies of the information (whatever be its nature) for the use of all the press, &c., in each town or district, through which such news passes. Under such arrangements, intelligence to the amount of two closely printed newspaper columns, or more, daily, is transmitted between all the stations, conveying information of the various share, corn, cotton, coal, iron, cattle, provision, and produce nun. 1 ,- xfc'ft.Ax/Co.irs^ shipping arrivals, foreign and domestic informa- news, whatever its nature, obtained "in" * Quarterly Review, No. CLXXXIX., pp. 139 14 1 . 88 USES OF THE TELEGRAPH. to all the rest; the arrival of vessels in Queenstown, the result of a market in Cork, or of a cattle fair at Ballinasloe, affording intelligence for the whole of the United Kingdom, and vice versa. In order to carry out this system, the company employs paid agents, news collectors, parliamentary reporters, &c. 253. It is a fact well known that the electric telegraph is much more extensively used for all purposes, political, commercial, and domestic, in the United States, than in this or any other part of Europe. Before the reductions which have within the last year or two taken place in the tariffs, this might fairly be explained by the comparatively small cost of transmission in America. But since those reductions were effected, it may be questioned whether there is any difference of cost sufficiently considerable to explain the vast difference in the extent to which the public, on different sides of the Atlantic, avail themselves of this mode of inter-communication. We shall notice the question of the tariffs hereafter. Mean- while, whatever be the cause, it is certain, that the practical use of the telegraph is much more extended among our transatlantic descendants. The tariffs vary on different lines, but it has been estimated that the cost of a message of 10 words, exclusive of address and signature, sent 10 miles, is about 5d., and for greater distances the cost may be taken at about 0-035d. per word per mile. The classes of messages entitled to precedence, are government messages, and messages for the furtherance of justice in detection of criminals, &c. ; then death messages, which includes cases of sickness when the presence of a party is sent for by the sick and dying. Important press-news comes next ; if not of extraordinary interest, it takes its turn with the mercantile messages. 2c4. Commercial houses resort largely to the telegraph. For ex- ample : a person purchasing goods in New York, gives his reference to the merchant such reference being perhaps 700 or 800 miles away from him. By the aid of the telegraph the merchant can learn the standing of his customer, even before the purchase is com- pleted. There are bankers, brokers, &c., that receive and send, on an average, six to ten messages per day, throughout the year. 255. The manager of House's line at New York states that some ^commercial houses pay to the company as much as 2007. a-year, and that the average annual receipts from twenty mercantile houses amount to 1007. each. The directors of Bain's New York lines report that the tele- tEelnai?. ' WL\Y^9J^S*dal^men to^almost^asj^at jm extent as sent and received between cities whose commercial relations are 89 THE ELECTRIC TELEGRAPH. intimate, during the hours from 10 A.M. to 5 p.ir. For instance : there are transmitted daily, between the cities of New York and Boston, between 500 and 600 messages, two-thirds if not three- fourths of which are transmitted between the Lours above named. .Some houses pay from 121. to 167. per month to the telegraph. The amount paid by a commercial house is governed by the excitement there is in the market of the particular article they may be dealing in. If there are "ups and downs" in the market, money is lavished upon the telegraph freely. The directors of the Morse New York lines, state that the annual telegraph outlay of several houses amounts to 6007. It often happens that a party desires to " converse" with another 400 or 500 miles off. An hour is appointed to meet in the respective offices, and they converse through the operator. Cases may be mentioned of steamboats being sold over the wires the one party being in Pittsburg, the other in Cincinnati. Each party wrote down what they had to say, higgled awhile, and finally concluded the sale. Their correspondence was filed away, like other messages, and kept for reference, if ever called in question. It is often used by parties, when from home, corre- sponding with their families. Sometimes it is the messenger of woe; and anon, that of pleasure. In the early part of 1852, the Astor House of New York, and the Burnet House of Cincinnati, had a series of telegraphic parties. An account of one of them was published in the "Cincinnati Gazette," the parties con- versing being about 750 miles apart. 256. The following example of the activity of journalism is given by Mr. Jones, who was himself a telegraphic agent for the news- papers: -"Some time back the Asia arrived at Quarantine, near New York, about 8 P.M., was detained an hour by the health officer. The agent of the New York Associated Press and of the New Orleans Merchants' Exchange, Mr. Jones, to gain but a few minutes, had a boat in readiness when the Asia brought to. A small bag containing the latest news was handed over the steamer's side, to the small boat. By great exertions sho gained New York half an hour ahead of the Asia. The bag was opened a copy of her news was handed to us, addressed to the Merchants' Exchange, New Orleans, signed Jones to work we went. It was being transmitted over the wires amid the thundering of the Asia's cannon, as she rounded the point ; and a complete synopsis of her commercial and political news was received in Louisville, 1100 miles in the interior, before the ship had actually reached the^city." _ iine at Hc>v Tork state ^^ during the sittings of conventions, or elections, or the arrival of 90 USES OF THE TELEGRAPH. steamers, often from 2000 to 8000 words are reported. On some occasions of market excitement, the private messages are nearly doubled. Debates of Congress are received at an average of about 4500 words per day, and transmitted at the rate of 1600 words per hour. On the assembly of the Legislature of the State of New York at Albany, in 1847, the governor's message, consisting of 25000 letters, was transmitted to New York, 150 miles, and printed by the telegraph itself in two hours and a half. 257. In his reports to Congress, Mr. Morse has supplied various examples of the use made of the telegraph by all classes of persons. During the Philadelphia riots of 1844, the mayor of that city sent an express by railway, to the President of the United States at Washington. On the arrival of the train at Baltimore, the con- tents of the express transpired, and the telegraph, which was then just put in operation between Baltimore and "Washington, not being yet established elsewhere in the States, sent on the substance of the despatch. The President held a cabinet council while the despatch itself was coming, and had his answer prepared and delivered to the messenger who brought the despatch at the moment of his arrival, who returned with it instantly to Philadelphia. 258. Nothing is more frequent in the United States than electric medical consultations. A patient in or near a country village desifes to consult a leading medical practitioner in a chief city, such as New York or Philadelphia, at four or five hundred miles distant. With the aid of the local apothecary, or without it, he draws up a short statement of his case, sends it along the wires, and in an hour or two receives the advice he geeks, and a prescription. Cases are recorded in wliich electric marriages have been contracted between parties separated one from another by many degrees of latitude. A correspondent of the author of a paper in Chambers' s Collection states, that in the United States, "The telegraph is used by all classes, except the very poorest the same as the mail. A man leaves his family for a week or a month ; he telegraphs them of his health and whereabouts from time to time. If returning home, on reaching Albany or Philadelphia, he sends word of the hour that he will arrive. In the towns about New York the most ordinary messages are sent in this way : a joke, an invitation to a party, an inquiry about health, &c. In our business we use it continually. The other day two different men from Montreal wanted credit, and had no references; we said: . 246 5 10 2 Derby to Peterborough . . . . 363! 5 9 6 Peterborough to Leicester . ... *59 3 Melton Mowbray to Stamford . . 54 2 2 2 Derby to Lincoln .,.-:>. '4*i 3 4 4 Derby to Sawley . . ; *i . . 6f i i I Derby to Normanton . ; . , . 44^4 7 15 T 4 21 I Normanton to Leeds . / . . 75i 7 7 3 Leeds to Bradford . ;. ; . 4' 3 5 4 Leeds to Skipton 7^ 3 7 6 Apperley to Shipley Cabin H 2 2 Skipton to Lancaster . . . . 78 2 I Hunslet to Hunslet Junction o| I 2 Hunslet Junction to Waterlane of I 2 2 Sheffield to Masbro' . . . . .' 15 3 2 2 Derby to Willington . j *- r .. .. 13 2 I z Derby to Birmingham . . . . j 2o6| 5 10 5 Birmingham to Gloucester . . . 371 7 H 6 Lickey to Bromsgrove 2 2 Gloucester to Bristol I * . . 150 4 8 MONMOUTHSHIRE RAILWAY AND CANAL, Newport to Blaina . . . . 39 2 7 Newport to Pontypool 17 2 3 Bisca to Nine Mile Point . . . *i I 2 2 Aberbeeg to Ebbw Vale . . 5i I 2 2 NORTH LONDON RAILWAY. Camden to Stepney . . . . 70 j 10 Bow to Poplar .... 3 2 3 NORTH STAFFORDSHIRE RAILWAY. Colwich to Macclesfield . . . 308 8 Included above. Colwich to Stone . . . , 46 4 3 Norton Bridge to Stone . . . * 3 2 2 Stone to Stoke . . . . 49 7 3 I Stoke to Loco Works . . i 2 2 Stoke to Burton 88$ 3 4 I 103 NAME OF RAILWAY. No. of Miles of Wires. No. of Wires. No ot Double-needle Instruments. 1- 11 =,5 1 No of Priutuig 1 Instruments. No. of Bells. No of Magnets. J Stoke to Newcastle-under-Lyne . . 3 2 2 2 Stoke to Horecastle .... 5 8 4 2 Stoke to Horecastle Tunnel . i 2. 2 Stoke to Crewe - l , r; j j: 7 J i 5 I I Stoke to North Rode . . 27 3 Included above. North Rode to Macclesfield . 5 3 I North Rode to Uttoxeter , . . 544 2 4 Rocester to Ashbourne 2 2 2 OXFORD, WORCESTER, & WOLVERHAMPTON 115 2 *3 2 Worcester to Dudley ; '. ; . . no 4 14 Dudley to Wolverhampton 24 4 3 SHREWSBURY AND BIRMINGHAM RAILWAY. Shrewsbury to Wolverhampton . . 118 4 9 I SHROPSHIRE UNION RAILWAY. Shrewsbury to Stafford 5** 2 3 SHREWSBURY AND CHESTER RAILWAY. Chester to Shrewsbury . . . 169 4 7 3 Wheatsheaf Branch . . 4 4 i i Oswestry Branch . . .... 9 4 i SHREWSBURY AND HEREFORD RAILWAY. Shrewsbury to Hereford . . - . ' 101 2 3 6 Ludlow Race-course . $*. 1 i 4 i Ludlow Tunnel ; r \ i . , ji 2 Dinmore Tunnel . ~ j ; i'. . . 4 4 2 2 NEWPORT, ABERGAVENNY, AND HERE- FORD RAILWAY. Hereford Junction to Hereford Station 82 2 3 HEREFORD, ROSS, AND GLOUCESTER RAILWAY. Grange Court to Hopebrook 10 2 2 SOUTH DEVON RAILWAY. Exeter to Plymouth . ... 371 7 7 *4 Newton to Totness . j. . 2 i Newton to Torquay . , j . . 20 4 3 Totness to Kingsbridge . I. 9 X 3 3 Plymouth to Kingsbridge . . . 15 I 3 3 WEST CORNWALL RAILWAY. Penzance to Truro .... 50 2 7 SOUTH-EASTERN RAILWAY. - . London to Strood . . .... 124 4 6 27 London to Greenwich 2 4 4 London to Observatory . . . . 74 2 For time signals. London to Tunbridge . 164 4 9 9 Tunbridge to Paddock Wood . . 25 5 2 2 Paddock Wood to Maidstone . . . 30 3 4 4 Paddock Wood to Dover . . . 168 4 2 3 15 109 NAME OP EAILWAY. II $* No. of Wires. No. of Double-needle Instruments. No. of Sinxle-needle Instrumems. 1 No. of Printing Instruments. No. of Bells. K o 1, Folkstone to Harbour . > . 6 6 3 3 Ashford to Margate .... IO2 3 8 8 Minster to Deal ,-?,;" P . 27 3 3 3 Ashford to Hastings . . . . 54 2 6 6 Tunbridge to Robert's Bridge 84 10 8 Robert's Bridge to Hastings . . . 24 2 3 3 Brighton Junction to Hastings . 6 2 3 3 Bricklayers' Arms to Junction . . 4 4 i i Redhill to Shalford . , ;. , , v> y 76 4 4 2 Shalford to Reading .... 54 2 7 Merstham Tunnel to Redhill 7 2 4 4 Redhill to Signal Pole .' . . o* I 2 SOUTH STAFFORDSHIRE RAILWAY. Bescott to Walsall . 1 4t | | , * . 7k 5 3 2 2 Bescott to Great Bridge . , . 6 2 2 Great Bridge to Dudley . -; . . ; 6 3 2 2 3 I Walsall to Brownhills .... I2 2 2 SOUTH WALES RAILWAY. Gloucester to Haverfordwest . . 647 4 35 2 6 6 Tunnel west of Landore 2 I 2 2 S.N.wirefrom S.W. to Taff Vale Railway oi I 2 2 Loop to Swansea .... H s 2 Cardiff Docks 5 4 I Gloucester to Grange Court *5i 2 I TAFF VALE RAILWAY. Cardiff Docks to Merthyr . . f 49 2 5 Aberdare to Aberdare Junction . 144 2 2 VALE OF NEATH RAILWAY. Neath to Merthyr ... . . 4 6 2 5 Hirwain to Aberdare Junction . i I 2 2 Merthyr to end of Tunnel . . . 2 I 2 2 WHITEHAVEN JUNCTION. Maryport to Whitehaven . 24 2 4 4 YORK, NEWCASTLE, AND BERWICK RAILWAY. York to Newcastle . . . . Darlington to Newcastle . 87*4 42! 10 18 13 I J 9 22 I 10 Darlington to Station on Stockton Line if I 2 Dalton to Richmond . . . . 19* 2 2 I Dalton to Darlington 5i I Belmont to Durham . . . . 12 6 4 Belmont to Fence Houses . 3i i 4 I Brockley Whins to South Shields . . 24 8 2 3 Newcastle to Brockley Whins . 47i 5 Included below. Brockley Whins to Sunderland . . 35 7 3 2 3 Newcastle to Berwick 399 6 8 7 110 NAME OF RAILWAY. No. of Miles of Wires. No. of Wires. INo. of Double-needle Instruments. 1 No. of Single-needle Instruments. No. of Printing Instruments. No. of Bells. No. of Magnets, j Newcastle to Benton . . . v ?t 4 I Newcastle to Tynemouth . 18 Z 4 Belton to Alnwick .... IZ 4 z I Fatfield to Washington 4 z I I Washington to Shields Drops . . . 8 z I I Shields Drops to Sunderland Dock 16 z I I Sunderland Dock to Sunderland Statn. 8 2 Included above. YORK AND NORTH MIDLAND RAILWAY. Harrowgate to Church Fenton . 4*| 3 z Z Hull to Milford Junction . . . 775 5 9 7 Bridlington to Hull . 3 ! 3 5 5 Scarborough to York . ... 3 8 7 Burton Salmon to Castleford . , 36* 9 z z Castleford to Normanton . . . 33l 9 z i Milford Juncton to Burton Salmon 4 2 Milford Junction to York . . . 3 3 2 z York to Burton Salmon . . & '3 10 8 EDINBURGH, PERTH, AND DUNDEE. Edinburgh to Tay Port . , V. 159 3 II ii Ladybank Junction to Perth 36 z Edinburgh to Scotland-street .. \ I z EDINBURGH AND GLASGOW RAILWAY. Edinburgh to Glasgow . . ... Edinburgh to Greenhill '* 7 2 9 3 7 Cowlairs to Hut Tunnel end . . 2 5 z z z Haymarket to Edinburgh Tunnel end . 3l 2 Edinburgh to Leith-street work . ' . 4 4 z DUNDEE AND ARBROATH RAILWAY. Dundee to Broughty . . . . 9 z I Tay Port Submarine cable . v,l \ f executing any kind of labour. By it coals are made to spin, weave, dye, print, and dress silks, cottons, woollens, and other cloths; to make paper, and print books on it when made ; to convert corn into flour ; to press oil from the olive, and wine from the grape ; to draw up metal from the bowels of the earth ; to pound and smelt it, to melt and mould it ; to forge it ; to roll it, and to fashion it into every form that the most way ward caprice can desire. Do we traverse the deep ? they lend wings to the ship, and bid defiance to the natural opponents, the winds and the tides. Does the wind-bound ship desire to get out of port ? they throw their arms around her, and place her on the open sea. Do we traverse the land ? they are harnessed to our chariot, and we outstrip the flight of the swiftest bird, and equal in speed the fury of the tempest. The substance by which these powers are rendered active is one which Nature has provided in boundless quantity in all parts of the earth, and though it has no price, its value is inestimable. This substance is WATEB. 5. Those who desire to comprehend clearly and fully this vast agency, to which so much of the advancement and civilisation of mankind is due, must learn successively, 1st. The principles on which heat is evolved from fuel ; 2nd. The expedients by which that heat is imparted to water ; 3rd. The quantity of it which is absorbed in the conversion of water into steam ; 4th. The mecha- nical power developed in this physical change ; and 5th. The mechanism by which that power is applied to industrial uses. It is obvious that the last of these points would include the exposition of the structure and operation of the varieties of steam- engines which have been applied to the purposes of commerce and manufactures, to railways and navigation. Upon this large subject it is not our present purpose to enter. We shall, however, explain the preceding, so as to enable our readers, with moderate 196 COMBUSTION OF FUEL. attention, to comprehend clearly the origin of the power of steam, and the physical conditions which determine its maintenance and its limits. 6. The general principles upon which heat is developed in the combustion of fuel have been already explained in our Tract on FIRE. It appears from what is there stated, that the varieties of coal are chiefly combinations of carbon and hydrogenous gases ? the proportion varying in different sorts, but the carbon entering into its composition in very large proportions in all cases. In different sorts of mineral combustibles, the proportion of carbon varies from 75 to 90 per cent. When carbon is heated to a temperature of about 700 in an atmosphere of pure oxygen, it will combine chemically with that gas, and the product will be the gas called carbonic acid. In this combination heat is evolved in very large quantities. This effect arises from the heat previously latent in the carbon and oxygen being rendered sensible in the process of combustion. The carbonic acid proceeding from the combustion is by such means raised to a very high temperature, and the 'carbon during the process acquires a heat so intense as to become luminous ; no flame, however, is produced. Hydrogen, heated to a temperature of about 1000, in contact with oxygen, will combine with the latter, and a great evolution of heat will attend the process ; the gases will be rendered luminous, and flame will be produced.* If coals, therefore, or other fuel exposed to atmospheric air be raised to a sufficiently high temperature, their combustible con- stituents will combine 'with the oxygen of the atmospheric air, and all the phenomena of combustion will ensue. In order, how- ever, that the combustion should be continued, and should be carried on with quickness and activity, it is necessary that the carbonic acid and other products should be removed from the combustible as they are produced, and fresh portions of atmospheric air brought into contact with it; otherwise the combustible would soon be surrounded by an atmosphere composed chiefly of carbonic acid to the exclusion of atmospheric air, and therefore of uncom- bined oxygen, and consequently the combustion would cease, and the fuel be extinguished. To maintain the combustion, there- fore, a current of atmospheric air must be constantly carried through the fuel : the quantity and force of this current must depend on the quantity and quality of the fuel to be consumed. It must be such that it shall supply sufficient oxygen to the fuel to maintain the combustion, and not more than sufficient, since * For the full explanation of this process, see Tract on Fire. 197 STEAM. any excess would be attended with the effect of absorbing the heat of combustion, without contributing to the maintenance of that effect.* The mechanical force of steam is developed in three ways I. By evaporation ; II. By expansion ; and III. By condensation. We shall accordingly explain these severally. Pig i. 7. I. POBCE DEVELOPED BY EVAPORATION. To render intelligible the manner in which a mechanical power is developed in the conversion of water into steam, and the circumstances which attend that remarkable physical change, we will suppose a quantity of pure water deposited in the bottom, A, of a tube, B A, fig. 1. To render the explanation more simple, we will suppose that the area of the section of the tube is equal to a square inch, and that the quantity of water deposited in it is a cubic inch. We will further imagine the tube to be glass, so that the phenomena developed in it may be visible. Let a piston, p, be imagined to be fitted in the tube, air tight and steam tight, and to be placed in immediate contact with the surface of the water, so as to exclude all communication between the water and the air above the piston. In this case the piston would be pressed upon the water by the pressure of the atmosphere upon a square inch of surface added to the weight of the piston itself. But the former pressure is equal to 15lb.,f and therefore the pressure on the surface of the water will exceed the weight of the piston by 15lb. Now to simplify our explanation by excluding all reference to the atmospheric pressure, and the particular weight of the piston, P, we shall suppose both of these exactly counterpoised by the weight, w, so that the piston shall be placed in contact with the surface of the water, without, however, exerting any pressure upon it. 1 These conditions being understood, let a weight, say of 15 lb., be placed upon the piston. P, and let a fire, a lamp or any other regular source of heat, be applied to the bottom of the tube. If a thermometer were immersed in the water under the piston, the following effects would then be observed : See Tract on Fire. t See Tract on Air. 198 EVAPORATION OF WATER. The thermometer would rise, the piston maintaining its position, and this would continue until the thermometer would rise to the temperature of 212. Upon rising to that temperature the thermometer would remain stationary, and at the same time the piston, P, would begin to rise, leaving a space apparently empty between it and the surface of the water. The lamp, or fire, still continuing to impart the same heat to the water, the thermometer nevertheless will remain stationary at 212, but the piston will continue to rise higher and higher in the tube, and if the depth of the water in the bottom of the tube be measured, it will be found that it is constantly diminished. If a sufficiently exact measure- ment of the decrease of the depth of water, and the height to which the piston is raised could be made, it would be found that the one would bear a fixed and invariable proportion to the other, the height of the piston being always 1669 times the decrease ot % the depth of water. . -. In fine, if this process were continued for a sufficient time, and if the tube had sufficient length, the water would altogether disappear from the bottom of the tube, and the piston would be raised 1669 inches, or 139 feet very nearly. For the convenience of round numbers, in a case where the most extreme arithmetical accuracy is not needed, we shall then assume that the piston loaded with 151b. has been raised 140 feet. 8. After this has taken place the tube below the piston will appear to be quite empty, the water having disappeared, and no visible matter having taken its place. If, however, the tube and its contents were weighed, they would be found to have the same weight precisely as they had when the water was deposited under the piston. The phenomenon is easily explained. The heat applied to the tube has converted the visible liquid water into invisible steam. It is a great but very common error to suppose that the whitish cloudy vapour which is seen to issue from the safety valve of an engine, or the funnel of a locomotive, or the spout of a boiling kettle, is steam. The semi-transparent matter which floats in the air, and continues to be visible for some time after it escapes from the boiler, is in fact not steam, but water existing in very minute particles, produced by the condensation of the steam by the contact of the colder air. When those particles coalesce and form small drops of water, they either fall to the ground or are evaporated at a lower temperature, and in either case disappear. If the vapour issuing from the safety valve of an engine, or the spout of a boiling kettle, be closely examined, it will not be found to have that cloudy semi-transparent appearance until it has passed to some distance from the point from which it issues. 199 STEAM. Pure steam is, in fact, a transparent and invisible elastic fluid like air, and this explains how it is, that in the tube, A B, the space below the piston, after the evaporation of the water, appears to be empty. It is, however, no more empty than if it were filled with air. It is filled with the invisible elastic vapour into which the water has been converted by the heat which has been applied to it. 9. It remains now to show what is the quantity of mechanical force evolved in this conversion of water into steam, and what quantity of heat has been absorbed in producing it. From what has been stated above, it appears that the water in passing into vapour has swelled into 1669 times its original bulk, being subject to a compressing force of 15 Ib. upon the square inch. In thus expanding, the weight of 15lb. has been raised 140 feet, an effect which is mechanically equivalent to 140 times 15 Ib., that is 2100 Ib. raised one foot. 10. To estimate the quantity of heat absorbed in producing this effect, let us suppose that in the commencement of this process, the water under the piston has the temperature of 32, and that the lamp, or other source of heat, which is applied to it acts with such uniformity as to impart exactly the same quantity of heat per minute. Let the time which elapses between the first application of tho lamp and the moment at which the water attains the temperature of 212 and begins to be evaporated, be observed, and also the interval between the commencement of evaporation and the total disap- pearance of the water. It will be found that the latter interval is 5| times the former. It follows consequently that to convert water at 212 into steam requires 5| times as much heat as is necessary to raise the same water from 32 to 212, or what is the same, the quantity of heat which would convert water at 212 into steam would increase the temperature of th'e same water by 5| times ISO", that is by 990, if it had remained in the liquid state. It follows also, that to convert water at 32 into steam will take 6| times as much fuel as would be sufficient to boil the same water. 11. It may be asked, what becomes of the enormous quantity of heat thus imparted to the water during the process of its evapo- ration, seeing that the water itself receives no increase of tempe- rature, being maintained steadily at 212, and that the steam into which it is converted has the same temperature ? This is answered by showing that the entire quantity of heat which thus disappears to the thermometer is absorbed by the steam, and must in fact be regarded as the immediate cause of its maintaining the elastic or vaporous form. That it is actually contained In the steam, though 200 FOKCE DEVELOPED IN EVAPORATION, its presence is not indicated by the thermometer, is incontestably established by the result of the following process : Let the steam, at 212, which has been evolved from a cubic inch of water at 32, be mixed with 5| cubic inches of water at the temperature of 32. The steam will be at once reconverted into water, and the mixture will be 6| cubic inches of water, the temperature of which will be 212. Thus it appears that the steam at 212, when reconverted into a cubic inch of water at 212, parts with as much heat as suffices to raise 5| cubic inches of water from 32 to 212, which is exactly the quantity of heat which disappeared while the water was converted into steam. The heat which is thus contained in steam, without affecting the thermometer, is said to be LATENT, and the latent heat of steam is therefore stated to be about 1000, the meaning of which is, that to convert boiling water into steam as much heat must be imparted to it as would raise it 1000 higher in temperature if it did not undergo that change of state. 12. In the preceding explanation we have supposed the piston r to carry a weight of 1 5 Ib. Let us now consider in what manner the phenomena would be modified if it were loaded with a greater or less weight. If it were loaded with 301b., the conversion of the water under it into steam would not commence until the temperature is raised to 251|, and when the whole of the water is evaporated, the piston would be raised to the height of only 883 inches, being a very little more than half the height to which it was raised when the evaporation took place under half the pressure. For all practical purposes, then, we shall be sufficiently accurate in stating, that when the weight on the piston p is doubled, it will be raised by the evaporation of a given quantity of water to half the height. In general, in whatever proportion the weight on the piston is increased, the height to which it is raised by the evaporation of a given quantity of water will be decreased, and in whatever pro- portion the weight is diminished, the height will be increased. 13. It follows, therefore, that in all cases, whatever be the pressure under which the evaporation takes place, the same mecha- nical force is developed by the evaporation of the same quantity of water. Strictly speaking, there is a little more force with greater pressures, but the difference is so small, and so nearly balanced by certain practical disadvantages attending high pressures, that it may be wholly disregarded. Since the amount of force developed by each cubic inch of water evaporated is equivalent to 2100 Ib. raised one foot, we shall be sufficiently near the truth in stating in round numbers that such a force is equivalent to a ton weight raised a foot high. 201 STEAM. It appears also, that under a pressure of 15 Ib. per square inch, water swells into 1669 times its bulk when it is converted into steam. Since a cubic foot is 1728 cubic inches, and since the mean atmospheric pressure is a little under 15 Ib., it may be stated with sufficient precision for all practical purposes, that a cubic inch of water, evaporated under the mean atmospheric pressure, will produce a cubic foot of steam. 14. II. FORCE DEVELOPED BY EXPANSION. Steam, in common with all vapours and gases, exerts a certain mechanical force by its property of expansibility. To render this source of mechanical power intelligible, let us suppose the piston p loaded at first with 60 Ib. for example, and under this pressure let the water be evaporated, and the piston raised to the height of 35 feet. The power thus developed will be that due to evaporation alone. But after the evaporation has ceased, and when the piston, with its load of 60 Ib., is suspended at the height of 35 feet, let 15 Ib. be taken from it, so as to leave a load of only 45 Ib. The pressure below the piston being then greater than its load, it will be elevated, and as it is elevated, the steam below it increasing in volume, will be diminished in pressure in the same proportion, until the piston is raised to a height equal to one-third part of 140 feet, when the pressure below it will be equal to the load upon it, and it will remain suspended. During this expansive action of the steam, therefore, 45 Ib. have been raised through a height equal to a difference between 1 and |, that is, through -^ of 140 feet. At this point let 15 Ib. more be supposed to be removed from the piston, so that its load shall be reduced to 30 Ib. The pressure below it being, as before, greater than its load, the piston will be raised, and will continue to rise, until it rise to a height equal to half of 140 feet, when the pressure, reduced by expansion, will become equal to the load, and the piston will again become suspended. In this interval 30 Ib. have therefore been raised by the expansive action of the steam, through the difference between | and ^ that is, through of 140 feet. Finally, suppose 15 Ib. more to be removed, and the piston will rise with the remaining 15 Ib. to the height of 140 feet, so that, in this last expansive action, 15 Ib. are raised through a height equal to the half of 140 feet. It is evident that the result of the expansive action may be indefinitely varied by varying the extent of its play. Meanwhile, whatever may be its amount, it is clearly quite 202 EXPANSION AND CONDENSATION. independent of the process of evaporation, and, indeed, of every property by which vapours are distinguished from air or gases, inasmuch as these latter, being similarly compressed, would similarly expand, and would develope in their expansion precisely the same force. 15. III. FOECE DEVELOPED BY CONDENSATION. It has been already explained* that as heat converts water into steam, so, on the other hand, will cold convert steam into water ; and as water, in passing from the liquid to the vaporous state, is swelled into a vastly increased volume, so, on the other hand, in passing from the vaporous to the liquid state, it suffers a proportionate diminution of volume. Thus if the evaporation take place under a pressure of 15 lb., a cubic inch of water is dilated into a cubic foot of steam, Now, if by the application of cold this steam is converted into water, it will resume its original dimensions, and will become a cubic inch of water. This change of vapour into water has therefore been called CONDENSATION, inasmuch as- the matter of which it consists, contracting into a much smaller volume, is rendered proportionally more dense. This property has supplied another means of rendering steam a mechanical agent, Let us suppose that after the piston p, fig. 1, has been raised 140 feet high by the evaporation of a cubic inch of water, the counterpoise, w, having descended through the same height, an additional weight of 15 lb. is placed upon TV, and, at the same time, the lamp withdrawn from the tube and cold applied to its external surface. The steam by which the piston was raised will then be converted into water, or condensed, and will, as at first, fill the bottom of the tube to the height of an inch. The space within the tube above the surface of the water extending to the height of 140 feet, will then be a vacuum, and the atmospheric pressure acting above the piston, not being resisted by any corresponding pressure below it, will force the piston down with a force of 15 lb., and will raiso the weight w, loaded with the additional 15 lb. through the same height. Thus, it appears that when steam is condensed, or reconverted into water, by producing a vacuum, it developes a mechanical force equal to that which was developed in the conversion of water into vapour. The mechanical power developed by the evaporation of water has been sometimes called the direct power, and that produced by the conversion of vapour into water the indirect power of * See Tract on Water, 203 STEAM. steam, because the immediate agent in the former case is the elastic force of the steam itself, while the agent in the latter case is the atmospheric pressure, to which effect is given by the vacuum produced by the condensation of steam. 16. The three sources of mechanical power which have been explained, have been used sometimes separately and sometimes together in different forms of steam engine. In the class of engines commonly called high-pressure engines, the direct power alone is used. In a class of engines, now out of use, called atmospheric engines, the indirect power alone was used. In the engines most generally used in the arts and manu- factures, known as low pressure or condensing engines, both powers are used. To obtain the mechanical effect of the vacuum produced by the condensation of steam, it is not necessary that the atmospheric pressure should be used. If we suppose that while the vacuum is produced below the piston P, steam having a pressure equal to that of the atmosphere be admitted to the upper side of it, the piston will be urged downwards into the vacuum with the same force exactly as if the atmosphere acted upon it. And, in effect, this is the method by which the indirect force of steam is rendered effective in all engines as at present constructed, the piston being in no case exposed to the atmosphere. 17. In the preceding illustration of the power of steam, we have supposed the piston P to have the area of a square inch, and to be raised continuously to the height of 140 feet. But it is evident that such conditions are neither necessary nor prac- ticable. If the piston had an area of ten square inches the same amount of evaporation would raise it to the tenth part of the height ; but the force with which it would be raised, being at the same time increased in a tenfold proportion, the me- chanical effect would be the same, for it is evident that whether 15 Ib. be raised 140 feet, or 10 times 15 Ib. be raised the 10th part of 140 feet, the same mechanical effect would be produced. The piston acted upon by the steam, instead of being continu- ously driven in one direction, may be alternately elevated and depressed, and still tho same amount of power will be developed. Thus the evaporation may be continued until the piston has been raised 10 foot. The steam which raised it may then be con- densed, and the piston having descended to the bottom of the tube, it may again be raised 10 feet by evaporation as before, and this may be continued indefinitely. In this way, by means of a short tube or cylinder, the mechanical effect attending the evapo- ration of any quantity of water may be obtained, and this, in 201 ACTION OF A PISTON. fact, is what is accomplished in steam engines as they arc practi- cally worked. Tho direct and indirect powers of steam may also be easily combined as well in the ascent as in the descent of the piston, If we suppose the upper part of the tube, instead of being open to the atmosphere, to communicate with a reservoir of water, to which, like the bottom of the tube, a lamp or other source of heat is applied, steam may be admitted above the piston p as well as below it. Now, if such be the case, it is easy to imagine how the piston can be at the same time affected by the direct and indi- rect power of the steam. Thus, if we suppose that a vacuum has been formed above it, by the condensation of steam, admitted from the upper reservoir, while steam produced from the lower reser- voir acts below it, the piston will be forced upwards by the com- bined effect of the direct action of the steam below and the indirect action of the condensed steam above, and when the pistoa has been thus raised, we can imagine that while steam is admitted above it from the upper reservoir, that which is below it may be condensed, in which case it will be forced down by the combined effect of the direct action of the steam above it and the indirect action of the condensed steam below it, and it is evident that such alternate action may be indefinitely continued. Such is the effect of the broad principle upon which all engines of the class called condensing, or low-pressure engines, are constructed. In their details there are numerous points of great practical importance and of much interest in a mechanical point of view. These arrangements, however, not affecting the principle of steam, regarded in its most general sense, need not here be further noticed. On a future occasion we shall explain such of them as have the greatest popular interest. 18. The apparatus by which the combustion of the fuel is effected, and by which the heat evolved is transmitted to the water to be evaporated, are furnaces and boilers of very various forms and construction, according to the circumstances in which they are applied, the one being adapted to the other, so that as much of the heat shall arrive at the water as the circumstances of their application permit. 19. The quantity of water which would be evaporated, if all the heat evolved in the combustion of a given weight of fuel could be transmitted to the water, is the THEORETICAL EVAPORATING POWER of the fuel, and the quantity of water actually evaporated by it is the PRACTICAL EVAPORATING POWER. The theoretical evaporating power varies with the quality of the fuel. A given weight of certain species of coal will evolve in combustion a greater or less quantity of heat than other species. 205 STEAM. In general, it may be stated that the strongest coals, meaning by that term those which have the greatest evaporating power, are those which are richest in carbon. The practical evaporating power of a given species of coal varies with the form, construction, and magnitude of the furnace and boiler. That portion of the heat which does not reach the water is dissipated in various ways. A part of it is lost by radiation from the grate ; a part by radiation from the boiler ; a part is carried by the heated gases of combustion into the chimney. The first two sources of waste of heat are reduced to a very small amount by a variety of ingenious contrivances. But the last is indispensable to the maintenance of the combustion, and ought to be considered as the power by which the furnace is worked, rather than a waste of heat. 20. The grate upon which the fuel is placed is surrounded on every side by parts of the boiler within which water is contained. In some boilers, even the ash-pit is a part of the surface of the boiler under which there is water. In this case, all the heat radiated from the grate, and the fuel upon it, is transmitted to the boiler ; and in all cases the furnace is surrounded on every side, except the bottom of the grate or ash-pit, with surfaces having water within them. 21. The waste of heat by radiation from the surfaces of the boiler, steam-pipes, cylinder, and other parts of the machinery in which steam is contained, or through which it passes, is dimi- nished by various expedients, which in general consist in surrounding such surfaces with packing, casing, or coating, composed of materials which are non-conductors, or at least very imperfect conductors of heat. In some cases the boiler is built round in brick work. In Cornwall, where economy is carried perhaps to a greater extent than elsewhere, the boiler and steam-pipes are surrounded with a packing of sawdust, which being almost a non-conductor of heat, is impervious to the heat proceeding from the surfaces with which it is in contact, and consequently confines all the heat within the boiler. In marine boilers it has been the practice recently to clothe the boiler and steam-pipes with a coating of felt, which is attended with a similar effect. When these remedies are properly applied, the loss of heat proceeding from the radiation of the boiler is reduced to an extremely small amount. The engine houses of some of the Cornish engines, where the boiler generates steam at a very high temperature, are frequently maintained at a lower temperature than the external air, and on entering them they have in a great degree the effect of a cave. 206 ECONOMY OF HEAT. The cylinders are often cased in wood. The boilers of loco- motive engines are always covered with a coating of boards. By these and many other expedients for the economy of heat, and more especially by the extensive application of the expan- sive force of steam, the mechanical power evolved from the combustion of coals k has been increased to an almost incredible extent. 22. A system of public inspection, of the performance of the engines worked in the mining districts of Cornwall, was established about forty years ago, which has been continued to the present time with the greatest advantage to the mining interests in particular, and to the engineering and commercial world in general. An exact account is kept, and periodical reports published of the quantity of fuel consumed by each engine, and the quantity of work done, the latter being expressed always by an equivalent weight, raised one foot high. The ratio of the fuel consumed to the weight thus raised is called the DUTY of the engine. 23. The improved efficiency of steam machinery is illustrated in a striking manner by these reports. It appears by them, that, in 1813, the average mechanical effect of a bushel of coals, applied in the best of the Cornish engines, was 11785 tons raised one foot. In 1837, this duty was 38935 tons raised one foot. The duty was therefore augmented in the ratio of 1 to 3. The increase of the mechanical efficiency of fuel has still gone on from year to year, and it may now be considered that a bushel of coals, of average quality, applied under good conditions of economy to the most efficient engines, is capable of producing a mechanical effect equivalent to 50000 tons raised one foot. 24. It follows, therefore, that a pound of coal has a mecha- nical virtue expressed by six hundred tons weight raised one foot high. 25. It is only by comparison with other physical agents that we can duly appreciate this prodigious mechanical power of coals. It is calculated that the materials composing the great pyramid of Egypt might have been elevated from the level of its base to their actual places by the combustion of 700 tons of coal. 26. Those of the Menai Bridge might have been raised from the level of the water by 400 Ib. of coal. 27. A train of coaches weighing 80 tons, and conveying 240 passengers, is drawn from Liverpool to Birmingham, and back from Birmingham to Liverpool by the combustion of 4 tons of coke, the cost of which is 51. To carry the same number of passengers daily on a common road would require an establish- ment of 20 stage coaches and 3800 horses. 207 STEAM. The circumference of the earth measures twenty-five thousand miles ; if it were begirt with an iron railway, such a train as above-described, carrying two hundred and forty passengers, would be drawn round it by the combustion of about three hundred tons of coke, and the circuit would be accomplished in five weeks. 28. The enormous consumption of coals produced by the appli- cation of the steam-engine in the arts and manufactures, as well as to railways and navigation, has of late years excited the fears of many as to the possibility of the exhaustion of our coal-mines. Such apprehensions are, however, altogether groundless. If the present consumption of coal be estimated at sixteen millions of tons annually, it is demonstrable that the coal-fields of this country would not be exhausted for many centuries. But in speculations like these, the probable, if not certain progress of improvement and discovery ought not to be overlooked ; and we may safely pronounce that, long before such a period of time shall have rolled away, other and more powerful mechanical agents will supersede the use of coal. Philosophy already directs her finger at sources of inexhaustible power in the phenomena of electricity and magnetism. The alternate decomposition and recomposition of water, by electric action, has too close an analogy to the alter- nate processes of vaporisation and condensation, not to occur at once to every mind : the development of the gases from solid matter by the operation of the chemical affinities, and their sub- sequent condensation into the liquid form, has already been essayed as a source of power. In a word, the general state of physical science at the present moment, the vigour, activity, and sagacity with which researches in it are prosecuted in every civilised country, the increasing consideration in which scientific men are held, and the personal honours and rewards which begin to be conferred upon them, all justify the expectation that we are on the eve of mechanical discoveries still greater than any which have yet appeared ; that the steam-engine itself, with its gigantic powers, will dwindle into insignificance in comparison with the energies of nature which are still to be revealed ; and that the day will come when that machine, which is now extending the blessings of civilisation to the most remote skirts of the globe, will cease to have existence except in the page cf history. 208 LONDON, December, 1854. WORKS PUBLISHED BY WALTON AND MABERLY, UPPER QOWER STREET, AND IVY LANE, PATERNOSTER ROW. 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