Heroes of the Telegraph/Chapter 4 > 공지사항

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The advantages are that each automobile is a complete and impartial unit and that the trolley-lines and feeder-system are abolished; however every line constructed has failed, and the trolley-system has been substituted. For underground railroads the electric system has not solely some great benefits of economy and effectivity however that of producing no smoke. The applying of electric traction to trains of greater than a number of automobiles requires a big electric locomotive or a special system of management, so that the motors on every could be managed by one motorman. One skilled gentleman in his evidence said these cables were "corresponding to nobody ought to have laid in deep water." It is ample at present to know that they have failed from neglect or inexperience, and that they, among other failures, have established the rules which have since insured success. Eleven years ago there was a joint committee appointed by the "Lords of the Committee of Privy Council for Trade and Atlantic Telegraphy, to inquire into the construction of submarine cables, together with different evidence." Attention is named in the report back to the "outstanding indisputable fact that in almost all circumstances small cables had been found liable to mishaps, whereas the heavier the cable had been the better had been its sturdiness." The report is full and complete, and establishes rules which up to the present time have uniformly assured success, while the neglect of them has as uniformly resulted in partial loss or failure.

That is certainly not a new subject for investigation, but in the present day I'm sure that it is going to be instructive to many among the hundreds who are actually fascinated on this class of property to have their attention briefly referred to as to all that has been done to make submarine cables a sound property. The design of the cable was a subject of experiment by Professor Morse and others. There is still nice room for enchancment upon the present technique of defending the exterior covering; of cables, and that i commend it to the additional careful research of telegraph-engineers as a topic of very important importance. Many accidents happened from inexperience in the method of paying out cables; at the current day the wonder is, that they should have succeeded so well with the rude strategies and inexperience which then existed, and never that there ought to have been many failures and far recrimination. This self-performing cable key was introduced out in 1876, and tried on the strains of the Eastern Telegraph Company. Gutta-percha, the adhesive juice of the Isonandra gutta tree, was introduced to Europe in 1842 by Dr. Montgomerie, a Scotch surveyor in the service of the East India Company.

Into this tent were introduced wires from India, America, Egypt, and different locations, and Lady Mayo despatched off a message to India about half-previous eleven, and had received a reply earlier than twelve, telling her that her husband and sons were fairly properly at five o'clock the subsequent morning. The underground cable consists essentially of a cylinder of insulating materials, resembling guttapercha, in that are imbedded a number of copper wires. One can go from Portland, Me., by means of Boston to New York metropolis by using the trolley-traces connecting the intervening towns. The line is divided into brief sections; every of those has an uncovered conductor, which could also be one of many rails, and that is positioned in short-term contact with the insulated conductor because the practice passes, by the stress of the wheels on a versatile rail or stud, or via computerized electromagnetic switches. The submarine hill, with its dangerous slope, was handed in security, and the 'telegraph plateau,' nearly two miles deep, was reached, when suddenly the indicators from Ireland, which informed that the conductor was intact, stopped altogether.

Day by day of my experience in watching over the permanence of the 10,000 miles of cable below my care, confirms me within the opinion that too great warning and vigilance can't be exercised in the making and laying a thread which is to be removed from all human imaginative and prescient forever, and designed to earn dividends by continuing a perfect conductor of electricity. It's to the mouse-mill that me should look both for the electricity which is used to electrify the ink and for the motive energy which drives the paper. When the environment is moderately humid, a correct provide of electricity is generated by the mouse-mill, the paper is sufficiently moist, electric cable and the ink flows freely. We now know that there are exceptional localities the place there's motion in the water at a depth of 500 fathoms. Cables have been recovered from depths of 1,200 fathoms with all of the hemp eaten away, and the core pitted with these marine animals. A terrific trigger of damage to cables is the corrosion of the external wires, attributable to moving water or marine vegetation, and so on., and this has established the general follow of overlaying the exterior wires with tarred yarn saturated with a mixture of pitch and silica.