The wounds opened farther under the various stimulating doses; the insulation was unable to bear the strain, and the circulation gradually ceased through a cable already in a state of dissolution.{155}
CHAPTER XI
THE INQUEST
Expert Trials—Expert Evidence
THE great historical sea-line having collapsed, some of the foremost of the electrical profession were called in—first to determine the nature of the interruption with a view to possible remedy, next to elicit the cause.
Expert Opinions on the Failure.—Mr. Cromwell Fleetwood Varley, the electrician to the Electric Telegraph Company, Mr. E. B. Bright, the chief of the “Magnetic” Company; and Mr. W. T. Henley, the well-known telegraph inventor, were severally requested by the “Atlantic” Company to report on the subject in conjunction with Sir Charles Bright and Professor Thomson.
First of all the dead line was subjected to a series of tests. For this, resistance-coils and Messrs. Bright’s apparatus for ascertaining the position of a fault were employed. There was every evidence of a serious electrical leakage about 300 miles from Valentia, but there did not appear to be any fracture in the conductor, as exceedingly weak currents still came through fitfully. According to the above location, the main leak through the gutta-percha envelope was in water of a depth of about two miles. At that time means were not devised for grappling and lifting{156} a cable from such depths. But from independent tests by Thomson and Bright, it appeared likely that the Valentia shore end was also especially faulty. Accordingly, it was underrun from the catamaran-raft (previously used in 1857) for some three miles, but, on being cut at the farthest point at which it was found possible to raise the cable, the fault still appeared on the seaward side. The idea of repairs had, therefore, to be abandoned, and the cable was spliced up again.
The conductor being again intact, efforts were made to renew signals with the curb-key recently invented by Messrs. Bright. By means of this, currents of opposite character were transmitted so that each signaling current was followed instantly by one of opposite polarity, which neutralized, by a proportionate strength and duration, all that remained of its predecessor. Though this was the right principle on which to work, the “patient” was too far gone, and all efforts proved unavailing; for signaling purposes the poor cable was defunct.
Having dealt with the nature of the interruption, we now come to the cause. It was first of all abundantly clear from the station-diaries kept by the electricians at Valentia and Newfoundland, and by other irrefragable evidence, that when the laying was completed, and the cable ends were handed over to them from the ships on August 5th, all was in good working order.
The authorities were unanimous in their opinion. Mr. C. F. Varley declared that “had a more moderate power been used, the cable would still have been capable of transmitting messages.” In giving extra force to the above opinion, Mr. Varley{157} described an experiment he had made on the cable in conjunction with Mr. E. B. Bright:
We attached to the cable a piece of gutta-percha-covered wire, having first made a slight incision, by a needle-prick, in the gutta-percha to let the water reach the conductor. The wire was then bent, so as to close up the defect. The defective wire was then placed in a jar of sea-water, and the latter connected with the earth. After a few momentary signals had been sent from the five-foot induction-coils into the cable, and, consequently into the test-wire, the intense current burst through the excessively minute perforation, rapidly burning a hole nearly one-tenth of an inch in diameter, afterward increased to half an inch in length when passing the current through the faulty branch only. The burned gutta-percha then came floating up to the surface of the water, while the jar was one complete glow of light.