I WITH A CABLE EXPEDITION. By Herbert Laws Webb. N these days of rapid development in new fields of electrical science and their commercial application, it is easy to overlook the magnitude of the work accomplished in the laying of deep-sea cables. According to the latest report of the International Bureau of Telegraph Administrations, the submarine telegraph system of the world consists of 120,070 nautical miles of cable. Government administrations own 12,524 miles, while 107,546 are the property of private companies. The total cost of these cables is in the neighborhood of two hundred million dollars. The largest owner of submarine cables is the Eastern Telegraph Company, whose system covers the ground from England to India, and comprises 21,860 miles of cable. The Eastern Extension, which exploits the far East, has 12,958 miles more. Early in last year the system of West African cables, which started from Cadiz only six years ago, was completed to Cape Town, so that the dark continent is now completely encircled by submarine telegraph, touching at numerous points along the coast. More than 17,000 miles of cable have been required to do this, and several companies, with more or less aid from the British, French, Spanish, and Portuguese governments, have participated in carrying out the work. The North Atlantic is spanned by no less than eleven cables, all laid since 1870, though I think not all are working at the present time; five companies are engaged in forwarding telegrams be tween North America and Europe, and the total length of the cables owned by them, including coast connections, is over 30,000 nautical miles. The cable fleet of the world numbers thirty-seven vessels, of an aggregate gross tonnage of about 54,600 tons. Ten ships belong to the construction companies, their aggregate gross tonnage being about half that of the entire fleet; the other twenty-seven are repairing steamers belonging to the different government and telegraph companies; they are stationed in ports all over the world, keeping a watchful eye on the condition of its submarine nerves, and doctoring them up whenever they need attention. The Silvertown and the Faraday head the list of cable ships in point of Copyright, 1890, by Charles Scribner's Sons. All rights reserved. both coasts of South America and on the west coast of Africa. This ship has exceptional capacity for carrying cable, her main tank being fifty-three feet in diameter and thirty feet deep, large enough to stow a good-sized house in. On one expedition she carried 2,370 knots of cable, weighing 4,881 tons, the whole length being coiled on board in 22 days, or at the rate of over 100 knots a day. Better still, she laid the whole length without a single hitch, much of it being paid out at the high speed of nine knots an hour. Among the repairing ships the best known is the Minia, the Anglo-American Telegraph Company's steamer, which patrols the North Atlantic, keeping the From Chart House. ing the adventures of voyaging with operations demanding the highest scientific skill and knowledge, and with the most ingenious mechanical work. The men brought together are, of course, of widely varied experience and accomplishments, each in his way an expert in some branch of electrical or mechanical engineering. It was the writer's good fortune, in 1883, to be connected with the technical staff of such a vessel the cable-ship Dalmatia - and he hopes that this narrative of his experiences will give a pleasant insight into the work of constructing the costliest and most wonderful half of Puck's girdle round the world. In the summer of that year the Span ish Government decided to establish telegraphic communication between the group of Atlantic islands known as the Canary Islands, and the Spanish Peninsula, by means of a submarine cable, and also to connect various of the principal islands of the group with each other by the same method. This important work was intrusted to a leading English cable manufacturing company with a very long name, commonly called for short, "The Argentville Company," from the name of the place where the company's works are situated. It was for the purpose of laying these cables that the Dalmatia and Cosmo mous factory on the banks of the Thames, a few miles below London. Here the birth of the cable may be traced through shop after shop, machine after machine. The foundation of all is the conductor, a strand of seven fine copper wires. This slender copper cord is first hauled through a mass of sticky, black compound, which causes the thin coating of gutta-percha applied by the next machine to adhere to it perfectly, and prevents the retention of any bubbles of air in the interstices between the strands, or between the conductor and the guttapercha envelope. One envelope is not sufficient, however, but the full thick politan made the voyage which I shall ness of insulating material has to be at describe. Let us first see what a submarine cable is, and how it is made. To do this a visit must be made to the enor tained by four more alternate coatings of sticky compound and plastic guttapercha. The conductor is now insulated, and has developed into "core." Before going any further the core is coiled into These tests are made from the testingroom, replete with beautiful and elaborate apparatus,* by which measurements finer and more accurate than those even of the most delicate chemical balance may be made. Every foot of core is tested with these instruments, both before and after being made up into cable, and careful records are preserved of the results. After the core has been all tested and passed, the manufacture of the cable goes on. The core travels through another set of machines, which first wrap it with a thick serving of tarred jute, and then with a compact armoring of iron or steel wires, of varying thickness according to the depth of water in which the cable is intended to be laid. Above the armoring, in order to preserve the iron from rust as long as A set of testing instruments for submarine-cable work, somewhat less elaborate than used in a cable factory, was illustrated on page 17 of SCRIBNER'S MAGAZINE for July, 1889. sian hemp as an additional preservative against corrosion. The completed cable is coiled into large circular store-tanks, where it is kept for some time submerged in water and again subjected to an exhaustive series of electrical tests. These tests form, so to speak, the baptismal record of the cable; by them it is ascertained whether the specifications have been complied with in respect to the maximum conductor resistance and the minimum insulation resistance which the cable is to have; in other words, whether the limits set by the purchasers of the cable on the amount of resistance in the conductor to the flow of the current, and the amount of leakage through the insulating envelope, have been exceeded or not. The shipment of the cable next claims. attention. The cable-steamer is lying at her moorings some distance out in |