« VorigeDoorgaan »
like manner the recording style covers over with blue lines all the surface of the paper excepting what forms the letters, thus
which may represent the letter O, as if written with white paint on a shaded ground. These electro-chemical telegraphs may, upon the principles we have described, transmit to a distance copies of profiles, or portraits, or outline drawings of any kind.
The art of photography has for a long time been employed in France for the detection and identification of thieves and other criminals. When the culprit is brought into the police office, his picture is instantaneously taken, and though he has learned to put his features on these occasions into contortions, yet the artist never fails to catch them in their natural state. Mr. Gardiner, the governor of Bristol goal, has recently introduced the same practice. His apparatus cost only £10, and the expense of working it is not above £5 per annum. The following case, which he has published, shows the great value of his plan, which he is anxious to have introduced throughout the kingdom. "J. H. came into the Bristol goal upon commitment for trial, a perfect stranger to me and my officers. He was well attired, but very illiterate. The state of his hands convinced me that he had not done any hard work, while the superiority of his appearance over his attainments led me to suspect that he was a practiced thief. I forwarded his likeness to several places, and soon received information that he had been convicted in London and Dublin. The London officer who recognized him by his portrait was subpœnaed as a witness, picked him out from among thirty or forty other prisoners, and gave evidence on his trial in October 1854, which led the Recorder to sentence him to six years' penal servitude." This admirable process may now be extended by means of the copying telegraph. We can not convey a photograph along a wire with its lights and shades, but an outline either of the whole person, or of the head, or profile, may be easily transmitted, and there can be no doubt that an outline of the culprit, even if the face is not seen at all, may often be sufficient for his identification.
The next telegraph that attracts our particular notice is the printing telegraph of Mr. J. Brett, who received a Council Medal at the Great Exhibition for this and other in
ventions connected with telegraphic communications which he exhibited. By this telegraph communications are sent in any lan
guage, and printed upon paper with considerable rapidity and precision. The paper and for a considerable time. Plumbago or verink are self-supplied from a store which lasts milion are considered preferable to printing ink, as they do not require to be so frequently replenished. Mr. Brett arranges his letters on the type wheel in the order of the frequency of their occurrence, which is as follows -e, t, a, i, o, n, s, h, r, w, d, l, c, f, m, u, b, g, p, j, y, k, v, x, q, z. He assures us, that messages may be printed more rapidly than a well-practiced person could write them; and that after a little experience, "a clerk might manipulate upon the finger keyboard upwards of 150 letters in a minute."
The American printing telegraph of Mr. House is a very complex but ingenious and useful instrument. It has at the transmitting station a key-board with each letter of the alphabet upon a key. When the operator presses down the key with the letter A, for example, the same letter A, which is a type upon a dial or wheel at the recording station, is brought by the electric current into a certain position, and having in its passage to this position received ink from the inking apparatus, a band or ribbon of paper is pressed against it and receives an impression of the letter. The next letter of the message is brought into its position in the same way, and as the ribbon of paper is drawn forward, its impression is made next to the letter A which preceded it. The advance of the ribbon, the inking of the type, and the pressure of the paper against it, are produced by an apparatus moved by the operator, at the recording station, by the action of a treadle. Grove's battery is used as the electric power, and about thirty cyclindrical pairs are required to produce the effect for a distance of 100 miles. This apparatus was first employed in 1849 upon the line between Philadelphia and New York. It is now in use on upwards of 1,358 miles of the American lines, and messages printed at the rate of from thirty to thirty-five words, or from 165 to 200 letters per minute, have been printed in common Roman character at a distance of 500 miles. The celerity of transmission must no doubt depend on the skill of the operator, for we are informed by Mr. Turnbull, that on one occasion 365 letters per minute, or upwards of six per second, were transmitted from New York to Utica, a distance of 240 miles. The average number, however, as we have stated already, is from thirty to thirty-five words per minute, or 500 letters, when, as a newspaper, abbreviations are allowed. In the
be wrought by the right and left hand of the operator, each telegraph working upon a separate wire. The object of the double instrument is to make the signals more rapidly, in consequence of a much greater number of signals being obtained by combining the deflections to the right and left of both needles. The dial telegraphs which are used in this country, as well as in France and Germany, all indicate letters and numbers upon a dialplate like that of a clock, the operator at the transmitting station turning the hand or index to a particular letter, and the operator at the transmitting station observing the index on his dial-plate pointing to the same letter. These effects, though of the same kind, are produced by different pieces of mechanism, differing more or less in their simplicity and ingenuity. The German telegraphs, however, constructed by Siemens, differ in one respect from all the rest. The dial is placed no-horizontally, and is surrounded by a circular key-board, the letter engraven on each key corresponding in position to that upon the dial. When the current is sent through the wires, the hand or the index of the dial-plate at all the stations on the line moves with greater or less rapidity like the seconds hand of a clock, with uninterrupted but regular motion, and on all the dial-plates upon the line the hand reaches the same letter at the same instant. When the operator at the transmitting station places his finger upon the key of the letter A, the revolving index is stopped on that letter at all the stations, in consequence of the current being stopped. After the proper pause, he transmits the next letter, and so on till the despatch is completed. In this very ingenious telegraph, the index describes the semi-circumference of the dial in a second, that is, it gives fifteen signals in a second. In order to obtain this velocity, a pile of five couples of Daniell's battery is sufficient at each station for each apparatus; but the number of couples required does not increase in proportion to the length of the telegraphic circuit which separates the instruments. With subterranean wires, M. Siemens found that for a distance of 50 German miles, a pile of 25 couples of Daniell's battery was sufficient; but this power is used only on lines where there are no intermediate stations. When there are such stations, instead of employing a more powerful battery, we have only to introduce into the circuit the electricity of the intermediate piles when despatches are to be sent between the extreme stations. M. Siemens, however, has invented an additional apparatus for working
autumn of 1850, a newspaper despatch of 7,000 words was transmitted from Syracuse to Buffalo in two hours and ten minutes, which is at the rate of fifty-four words in a minute.
The telegraphs most commonly used in this country are what have been called the Needle and the Dial Telegraphs. The first transmits messages by signals or the different positions of a magnetic needle, and the second by pointing in succession to the different letters of the messages upon a dial-plate containing the letters of the alphabet and numerals. Although the telegraphs of both these constructions perform their work well, yet it seems to be the general opinion that the dial telegraphs are more easily wrought and less subject to error. In the needle telegraphs each signal is independent of those which precede it, so that in making up the despatch the operator does not discover the error, whereas in the dial telegraph he tices any incoherence in the despatch while he is reading it, as it were, upon the instru
The single needle telegraph consists of a galvanometer or coil of wires for strengthen ing electric current, and a commutator apparatus, by turning the handle of which in different directions, the current may be either stopped or inverted in its direction. A magnetic needle is placed within the galvanometer, but on the same axis is placed another needle which may be either magnetic or not, but which, while following all the motions of the magnetic needle, indicates upon a dial plate the letters or signals which are to be transmitted, or which are received. The alphabet is placed into two halves, the first half from A to L on the left hand of the needle standing vertically, and the other half from L to Y on the right hand of it. Beneath each letter is placed the number of motions of the needle by which the letter is expressed, the needle moving to the left for the first half, and to the right for the second half of the alphabet. In like manner a row of numerals is placed beneath the lower end of the needle, those from 1 to 6 on the left hand, and from 6 to 9 and 0 on the right hand, and the number of motions of the lower half of the needle which correspond to them is placed above them. The letter M, for example, is indicated by one click and motion of the upper half of the needle to the right, and the letter A by two clicks and motions of the needle to the left.
The double needle telegraph is merely a combination of two single ones, which can
the telegraph at great distances without | greatly increasing the strength of the battery. He has constructed also a very ingenious apparatus for printing the despatch by the ordinary type upon a ribbon of paper; but though it was generally used in Prussia for a considerable time, it has been replaced by the more rapid printing process of Morse.
Having thus given a brief history of the different proposals that were made during the last hundred years to construct electric telegraphs by persons who did not realize their schemes, and perhaps were not fitted to realize them, and described, in a very general manner, the more interesting as well as the more common forms of this noble instrument, we shall now endeavor to give a popular and general account of the labors of those individuals who have the high merit of having introduced the electric telegraph into actual use, either for private or public purposes.
MM, Gauss and Weber of Göttingen, were decidedly the first persons who applied an electric telegraph to purposes of actual utility. So early as 1833, they had erected a telegraphic wire between the astronomical and magnetical Observatory of Göttingen, and the Physical Cabinet of the University, for the purpose of carrying intelligence from the one locality to the other; but the wire was destroyed on the 16th December, 1833, by a flash of lightning which struck it at the place where it passed the top of the Tower of St. John. They employed the phenomena of magnetic induction discovered by Mr. Faraday; and their signals were made by the different movements and oscillations of a magnetic needle observed through a telescope."
The merit of inventing the modern telegraph and applying it on a grand scale for public use is, beyond all controversy, due to Professor Morse of the United States. So early as the year 1832, in the month of October, when on board the packet boat Sully, he described his invention to W. Pell, the captain of the packet boat, and to Mr. Rives, the Minister of the United States to the French Government. Both these gentlemen bear testimony to the fact in the most distinct manner and though an unsuccessful attempt has been made to rob the American professor of his just rights, by asserting that a Mr. Jackson had communicated the invention to him on board the same packet
See Göttingische gelehrte Anzeigen, August 9, 1834. No 128, pp. 1273, 1274, and 1834, No. 36. † Comptes Rendus, &c., tom. vii. p. 593.
boat,* yet Mr. Jackson never prosecuted his views and turned them to public use; and even if, without any other evidence in his favor but his own, we were to admit that he did make a useful communication to his fellow-passenger, this would only make the invention more clearly an American one, and would still leave to Professor Morse the high merit of having realized the idea of another, and made it of general use to his own country and to Europe. While men high in office, and even men of science on both sides of the Atlantic, entertained doubts of the applicability and practical use of the telegraph, Professor Morse was actively engaged in pressing the importance of his invention on the attention of Congress, and "though only half convinced, by his earnestness and demonstrations, the federal legislature consented to make the experiment, and with that view appropriated a sum of money for the construction of a telegraph forty miles in length between Washington and Baltimore. This may be considered as the parent telegraph of the transatlantic world, from which a system has since sprung which, from its extent and achievements, is well calculated to fill both native and foreigner with astonishment."t
Morse and his coadjutors took up the subject of the electric telegraph, not as a mere adjunct of a railway for railway purposes chiefly, but as a great national instrument for the rapid conveyance of intelligence, entirely independent of the railway system, and which might have been established if railways had never existed. The American telegraphs have therefore the peculiar character of not always following the railway lines, but of pursuing a shorter path from point to point through a wild, broken, and uncultivated country through which no railway could be carried. Many places have, therefore, been brought into telegraphic communication with each other between which no railway exists, and the inhabitants of distant and inaccessible localities, who never can expect the luxury of railway transport, are provided with all the advantages of telegraphic communication.
Owing to the independence of the telegraph system of lines of railway, it has necessarily made a more rapid progress in America than in any other part of the world. A large number of independent Companies have been established, and new ones are con
* Idem, tom. viii. p. 345.
+ Mackay's Western World, vol. ii. p. 252.
stantly forming, each surpassing its predeces- | sons who erected a real modern telegraph,
we must name M. Steinhill of Munich. The
End of 1853.
Morse's lines, 19,963 miles.
the increase in little more than a year being 17,017 miles. The capital employed upon these lines is about a million and a half sterling.
A line of enormous magnitude, uniting the Pacific and Atlantic oceans, has been projected from Natchez in the State of Mississippi to San Francisco in California, a distance of 2,400 miles, and a Company is said to be organized to carry out this scheme with a capital of upwards of a million sterling. When this line is completed, and Newfoundland joined by a submarine or transmarine telegraph with the old world, a message may be conveyed from Europe to the Pacific in less than a day.
This great extension of telegraphic com
munication in America arises from the exten
sive use which is made of it by all classes of society as a method of transmitting and receiving intelligence. The price of a message of ten words sent ten miles is about fivepence, and for greater distances it is about 0.035 pence per mile. The mes sages of the government have always the precedence, those for detecting criminals come next, then death messages, then cases of sickness. Important news by the press are next sent. Commercial men use the telegraph to a great extent, some houses paying even £200 per annum. Parties converse with one another at the distance of 500 or 700 miles. Sales are effected by itabsent friends correspond with their families -medical consultations pass along the wire, and in the towns near New York, invitations to a party, inquiries about health, and even jokes, all tremble along the copper line.
As one of the earliest inventors of telegraphic apparatus, and one of the first per
ABDEF G H CH SCHIK L M N O P
The ten numerals are distinguished in a similar manner. This telegraph was established in July, 1837, and consequently it must have been invented, and its invention known, some time before. It commenced at the observatory of M. Steinhill in the Lerchenstrass of Munich, where the conducting wire was united to a plate of copper six inches square, buried in the ground. From
this the wire passed over the houses to the Academy of Sciences, where the second station was established. From this it went to the Royal Observatory at Bogenhausen, where there was a third station, and where the wire terminated in a plate of copper six inches square buried in the ground.
These steps, however, though very important, were not be to compared with the bold and successful attempt to carry a submarine cable from Dover to Calais. In 1850, M. Steinhill, to use his own words, "thinks the Submarine Telegraph Company made the that he has invented the first telegraph in necessary arrangements with the French and the true sense of the word, that is to say, an Belgian Governments, and Messrs. Newall apparatus which speaks a language easily and Co., the celebrated wire-rope makers of comprehended, and which writes what it Gateshead, were intrusted with the manuspeaks, or rather what we wish it to speak."* facture of 24 miles of a wire-cable, to stretch We concur with the inventor that this is the over a distance of 21 miles.* For this purcharacter of his telegraph, and we do not hesi- pose, four copper wires, the sixteenth of an tate to express our admiration of the sagacity inch in diameter, were covered with successand ingenuity which it displays in all its ive coatings of gutta percha. The wires parts. The fact that the earth may be used were then twisted together, and surrounded as one half of the conductor, is a discovery with a mass of spun yarn soaked in grease of vast importance, made, independently we and tar, so as to form a compact rope imperdoubt not, by him, but we owe it to Sirvious to water. In order to give strength to William Watson, who, in 1747, completed this combination, and protect it from external the circuit at great distances by water, and injury, ten galvanized wires are twisted round even by two miles of dry ground. But the rope, so as to form a submarine cable. while we give this well-merited praise to M. This cable was completed in three weeks, but Steinhill, we are not prepared to admit that owing to an accident in laying it down, it his was the first real telegraph of the mod- suffered a twist or bend, which took it out of ern type." The claims of Professor Morse the direct line and prevented it from reaching can not be overlooked, either as an inventor to Saugat, south of Calais. It was necessary, of telegraphic apparatus, or an active intro- therefore, to add to it another mile of cable, ducer of his invention as a national improve- which being immediately done, though the ment. With all its ingenuity, the Bavarian task was not an easy one, the communication telegraph had undoubted disadvantages, and between Calais and Dover was completed on we are told "that M. Steinhill himself has the 17th October 1851, and since that time, abandoned it in favor of a modification of the Great Britain and the Continent of Europe instrument of Morse." have, by this iron larynx, conversed with each other on every subject which can interest humanity. The expense of the cable was £9,000, and the station at Dover and Calais, £6,000. This line of telegraph belongs to the Chartered Submarine Telegraph Company.
The first promoters of the Electric Telegraph, sanguine as they were of its ultimate triumph over the prejudices of the railway companies, who at first rejected it, and of supine governments, who were blind to its advantages, and never contributed to its extension, they yet never anticipated that its lines would span wide arms of the sea, and, by crossing even oceans themselves, would girdle the terraqueous globe. The submarine telegraph was not a corollary of the terrestrial. It was a new idea, which it required genius to suggest, and science to realize. Dr. O'Shaughnessy, so early as 1839, succeeded in laying down an insulated conducting wire, attached to a chain-cable in the River Hoogly, which carried the electric current from one bank to another. Another step was made in 1847, by M. Siemens, who first applied gutta
percha to the insulation of the wires, and laid down a telegraphic line to cross the Rhine at Cologne.
See Comptes Rendus, &c. tom. vii. p. 590-93. where he has described his invention.
+ Phil. Trans. 1747, or Priestley's Electricity, pp.102-109.
By the private enterprise of Messrs Newall and Company, a still longer submarine cable was stretched across the Irish Channel from Holyhead to Dublin, or rather to Howth. In the deep sea portion of it, the gutta percha rope containing one copper wire, was surrounded by ten twisted iron wires, and the shore ends of the same rope surrounded by six iron wires. Transported from the works at Gateshead on twenty wagons, it was sent by railway to Maryport, where the Britannia carried it to Holyhead. On the 4th of June 1852, it was deposited in the Irish Channel, where the depth of water is 70 fathoms,
* An unsuccessful attempt had been made in 1850, when the cable broke by the action of the waves rubbing it against a ridge of rocks near Calais, at Cape Gris-nez.