The 1teamship North Star, from Southampton, arriving at this port July 20, brought news of the failure of the enterprise. The Niagary, and Gorgon arrived at Queenstown, Ireland, on the 5th, and the Agamemnon and Valorous had not arrived on the 7th. The two larger ships met on the 28th of June, and for the third time connected the cable ; they then started afresh, and the Niagara having paid out over one hundred and fifty miles of cable, all on board entertained the most sanguine hopes of success, when the announcement was made on the 29th at 9 P. M., that the electric current had ceased to flow. As the necessity of abandoning the project for the present was now only too manifest, it was considered that the opportunity might as well be availed of to test the strength of the cable. Accordingly, this immense vessel, with all her stores, &c., was allowed to swing to the cable, and in addition, a strain of four tuns was placed upon the breaks, yet, although it was blowing fresh at the time, the cable held her as if she had been at anchor, for over an hour, when a heavy pitch of the sea snapped the rope, and the Niagara bore away for Queenstown. She must have passed the Agamemnon, but owing to the heavy fogs missed seeing or gaining any tidings of her. It was conjectured that the latter may have returned to the place of meeting. Should nothing be heard of her, the Niagara would, after coaling, proceed to the ocean station. Having still on board 1800 miles of the cable, which, supposing the other vessel has retained a similar amount, would still permit the junction being completed, and allow 30 per cent for casualties. These repeated failures have taught us something. Professor Morse, thinking from the results that the cable is too thick, and many others that it is too thin ; the Professor's view is, however of the greatest value, and shonld be tested by a practical experiment. The Evening Post, of this city, in an able article on this subject, concludes with the following axioms, which every one having common sense must indorse : "A cable coiled cannot be uncoiled without kinks: " Therefore the cable must be reeled to be laid. " The necessity of two vessels to lay the cable, quadruples (and more) the risk of acci. dents : " Therefore the cable must be laid from one ship. " The voyage to England is easier, shorter and safer than the voyage from England : " Therefore the vessel with the cable should start from this side. " There is one vessel, and one only, of tun-nage and room sufficient to carry the whole cable, to witthe Great Eastern : " Therefore, the cable, if ever laid at all, must be stowed on a succession of reels in the Great Eastern, and that ship must sail from ' our own shores." If these views should be deemed to possess any Talue, it would be easy for the Great Eastern to bring the cable with her to this country and lay it on her first trip home. While acknowledging the numerous difficulties in the way, we cannot be persuaded to despair, because we know that ultimately the cable must and will be laid. Since the above was written, the following intelligence was received in this city : Washington, July 24, 1858. Captain Hudson, in a lettet: to the Navy Department, dated Queenstown, July 8th, says that the Niagara was then awaiting the arrival of the Agamemnon and Valorous, when he hoped to start again for the rendezvous in seven or eight days, under more favorable auspicee of weather than experienced in June.