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 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. Professor Hughes, the inventor of the type-printing telegraph, and, subsequently, of the microphone, considered that "the cable was injured by the induction-coils, and that the intense currents developed by them were strong enough to burst through gutta-percha." Professor Wheatstone gave a similar opinion. Some one inquired of the electrician whether, if any one touched the cable at the time when the current was discharged from the induction-coil, he would receive a shock sufficiently strong to cause him to faint. It was admitted in reply that "those who touched the bare wire would suffer for their carelessness, though not if discretion be exercised by grasping the gutta-percha only."