Two topics seem at present to occupy the minds of everybody here; one, the successful laying of the cable, the other the burning of the quarantine buildings on Staten Island. We were quite unconscious, when passing the spot yesterday, that the whole of these buildings had been destroyed on the preceding night by an incendiary mob; for such we must style the miscreants, although they comprised a large portion, it is said, of the influential inhabitants of the place. The alleged reason was that the Quarantine establishment was a nuisance, and the residents had for months been boasting of their intention to destroy the obnoxious buildings. The miserable inmates would have perished in the flames, had not some, more charitable than the rest, dragged them from their beds. The Yellow Fever Hospital is destroyed, and the houses of the physicians and health officers are burnt to the ground. At the very same moment New York itself was the scene of the splendid festivities in honour of the successful laying of the Atlantic Telegraph Cable, to which we have alluded. We came in for the _finale_ of these yesterday, when the streets were still much decorated. In Trinity Church we saw these decorations undisturbed: the floral ornaments in front of the altar were more remarkable, however, for their profusion than for their good taste. On a temporary screen, consisting of three pointed gothic arches, stood a cross of considerable dimensions, the screen and cross being together about fifty feet high. The columns supporting the arches, the arches themselves, and all the lines of construction, were heavily covered with fir, box, holly, and other evergreens, so as to completely hide all trace of the wooden frame. The columns and arches of the church were also decorated with wreaths and garlands of flowers. On a panel on the temporary structure already mentioned was the inscription, "GLORY BE TO GOD ON HIGH, AND ON EARTH PEACE, GOOD WILL TOWARDS MEN," all done in letters of flowers of different colours; the cross itself being covered with white roses and lilies. In the streets were all sorts of devices, a very conspicuous one being the cable slung between two rocks, and Queen Victoria and the President standing, looking very much astonished at each other from either side. The absurdity of all this was, that the cable had really by this time come to grief: at least, on the morning after our landing, an unsuccessful attempt was made to transmit the news of our arrival to our friends in England. It was rather absurd to see the credit the Americans took to themselves for the success, such as it was, of the undertaking.