The industries are equal in importance to the transit trade, and embrace metalworking, ironfounding and machine building, the manufacture of electric plant, celluloid, automobiles, furniture, cables and chemicals, sugar refining, cigar and tobacco making, and brewing.
In 1859 he began, in concert with Sir William Thomson (afterwards Lord Kelvin), to work on problems respecting the making and use of cables, and the importance of his researches on the resistance of gutta-percha was at once recognized.
Telegraphic communication with Europe is effected by cables laid along the Uruguayan and Brazilian coasts, and by the Brazilian land lines to connect with transatlantic cables from Pernambuco.
Fully three-fourths of the state contributions is expenditure on military necessities; in addition there are subventions to various colonies and to colonial railways and cables, and the expenditure on the penitentiary establishments; an item not properly chargeable to the colonies.
While Cook was speculating on the cause of this phenomenon, and was in the act of ordering out the boats to take soundings, the " Endeavour " struck heavily, and fell over so much that the guns, spare cables, and other heavy gear had at once to be thrown overboard to lighten the ship. As day broke, attempts were made to float the vessel off with the morning tide; but these were unsuccessful.
The paper cables consist of a number of wires, each enveloped in a loose covering of well-dried paper, and loosely laid up together with a slight spiral " lay " in a bundle, the whole being enclosed in a stout lead pipe.
The underground system of paper cables has been very largely extended, Cables between London, Glasgow, Edinburgh, Liverpool.
The one disadvantage of paper cables is the fact that any injury to the lead covering which allows moisture to penetrate causes telegraphic interruption to the whole of the enclosed wires, whereas if the wires are each individually coated with gutta-percha, the presence of moisture can only affect those wires whose covering is defective There is no reason for doubting, however, that, provided the lead covering remains intact, the paper insulation is imperishable; this is not the case with gutta-percha-covered wires.
5-7), as usually manufactured, consists of a core a in the centre of which is a strand of copper wires varying in weight for different cables between 70 and 650 lb to the nautical mile.
Of two transatlantic cables laid in 1894, the core of one consisted of Soo lb copper and 320 lb gutta-percha per mile, and that of the other of 650 lb copper and 400 lb gutta-percha; whereas for the similarly situated cable laid in 1866 the figures were 300 lb copper and 400 lb gutta-percha.
- Sections of three types of Submarine Cables, full size.
Cables have frequently been picked up showing after many years of submergence no appreciable deterioration in this respect, while in other cases ends have been picked up which in the course of twelve years had been corroded to needle points, the result probably of metalliferous deposits in the locality.
Of the deep-sea cables within the first twelve years, placed the probable life of a cable as low as fifteen years, but the weeding out of unserviceable types of construction, and the general improvement in materials, have by degrees extended that first estimate, until now the limit may be safely placed at not less than forty years.
Since by international agreement the wilful damage of a cable has been constituted a criminal offence, and the cable companies have avoided crossing the fishing banks, or have adopted the wise policy of refunding the value of anchors lost on their cables, the number of such fractures has greatly diminished.
In the ordinary methods, a differentially wound receiving instrument was used, one coil being connected with the cable Company and the various Atlantic cables, are worked duplex on method of duplexing a cable was described by Lord Muirhead's plan.
In this, as Most important cables, such as those of the Eastern Telegraph and the other with the earth; but it differed from other methods in requiring no " artificial " or balancing cable.
It was not, however, a sufficiently perfect representation of a laid cable to serve for duplexing cables of more than a few hundred miles in length.
This system of duplexing cables has proved remarkably successful.
For working long submarine cables the apparatus ordinarily employed on land lines cannot be used, as the retarding effect of the electrostatic capacity of the cable is so marked that signals fail to be recorded except at a very slow speed of working.
The arrangement of the apparatus for working some of the most recent cables is shown in Fig.
When the key is released the condensers and cables at once begin to return to zero potential, and if the key is depressed and released several times in rapid succession the cable is divided into sections of varying potential, which travel rapidly towards the receiving end, and indicate their arrival there by producing corresponding fluctuations in the charge of the condenser C3.
All cables of any great length are worked by reverse currents.
The general principle on which the instruments for working long submarine cables are based is that of making the moving parts very light and perfectly free to follow the comparatively slow rise and fall of the electric impulses or waves.
31, from one of the Eastern Telegraph Company's cables about 830 miles long.
Owing to the difficulty of maintaining perfect balance on duplexed cables, curb sending is not now used, but the signals are transmitted by means of an apparatus similar to the Wheatstone automatic transmitter used on land lines and differing from the latter only in regard to the alphabet employed; the signals from the transmitter actuate a relay having heavy armatures which in turn transmit the signals to the cable; this arrangement gives very firm signals, a point of great importance for good working.
This was followed by various other cables between England and the neighbouring countries, and their success naturally revived the idea which had been suggested in 1845 of establishing telegraphic communication between England and America, though this enterprise, on account of the distance and the greater depth of water, was of a much more formidable character.
These two cables did not have a very long life, that of 1865 breaking down in 1877 and that of 1866 in 1872, but by the later of these dates four other cables had been laid across the Atlantic, including one from Brest to Duxbury, Mass.
The submarine cables of the world now have a length exceeding 200,000 nautical miles, and most of them have been manuf actured on the Thames.
France and Great Britain jointly acquired the cables between Calais and Dover, Boulogne and Folkestone, Dieppe and Beachy Head, Havre and Beachy Head, Piron, near Coutances, and Vieux Châteaux (St Heliers, Jersey).
Belgium and Great Britain became joint-proprietors of the cables between Ramsgate and Ostend and Dover and De la Panne (near Fumes).
The two cables to Holland and one of the cables to Germany were already the property of Great Britain, and the German Union Company's cable to Germany was purchased by the German government.
In 1896 it was arranged to lay two new cables to France and one (for duplex working) to Germany.
Underground, and the total lengths of submarine cables of the world were 39,072 nautical miles under government administration and 194,751 nautical miles under the administration of private companies.
On submarine cables see also the works of Sir Charles Bright's son, Mr Charles Bright, F.R.S.E., A.M.Inst.C.E., M.I.E.E.; e.g.
The difficulty of connecting lightships and isolated lighthouses to the mainland by submarine cables, owing to the destructive action of the tides and waves on rocky coasts on the wll- shore ends, led many inventors to look for a way out of the difficulty by the adoption of some form of inductive Smith.
It is still used locally for making shoes, ships' cables, mats and a kind of spun cloth.
In large towns telephone distribution by means of open wires is practically impossible, and the employment of cables either laid in the ground or suspended from poles or other overhead supports is necessary.
These pairs are laid up symmetrically into cables, each layer being protected with an additional covering of paper and all adjacent layers revolving with an opposite twist.
Actual or projected routes for telegraph cables across the deep sea have also been sounded with extreme accuracy in many cases; but beyond these lines of sounding the vast spaces of the ocean remain unplumbed save for the rare researches of scientific expeditions, such as those of the " Challenger," the " Valdivia," the " Albatross " and the " Scotia."
In the operation of intra-urban railwa y s, steam locomotives, cables and electricity have severally been tried: the first having been used in the earlier examples of underground lines and in the various elevated systems in the United States.
Two submarine cables start from Otranto, one for Valona, the other for Corfu.
The metallurgic industries are well developed, and consist in the production of iron, steel, machinery, small-arms, lead articles, wire-cables and rails.
A coastwise cable runs from Para to Montevideo with double cables between Pernambuco and Montevideo.
Subsequently Sir Charles Bright supervised the laying of submarine cables in various regions of the world, and took a leading part as pioneer in other developments of the electrical industry.
In conjunction with Josiah Latimer Clark, with whom he entered into partnership in 1861, he invented improved methods of insulating submarine cables, and a paper on electrical standards read by them before the British Association in the same year led to the establishment of the British Association committee on that subject, whose work formed the foundations of the system still in use.
Petroleum refineries, iron-foundries, chemicals, soap-boiling, silk-spinning and the production of ships' fittings, as marine steam boilers, anchors, chains, cables, are the other principal branches of industry.
Telegraph and telephone cables join these ports, but a regular passenger route does not exist owing to the unsuitability of Portpatrick.
Brewing, saw-milling, boat-building, and the manufacture of biscuits, soap and submarine cables are also carried on.
Emden is also of importance as the station of the submarine cables connecting Germany with England, North America and Spain.
This formula is important in connexion with the capacity of electric cables, which consist of a cylindrical conductor (a wire) enclosed in a conducting sheath.