Italian, as he told us he was--we went up the ladder of the church spire. Once on the wooden platform, we could hear more distinctly the boom of the guns, which sounded like the broadsides of a big vessel. Were they the guns of Persano's long inactive fleet attacking some of Brondolo's or Chioggia's advanced forts? Were the guns those of some Austrian man-of- war which had engaged an Italian ironclad; or were they the 'Affondatore,' which left the Thames only a month ago, pitching into Trieste? To tell the truth, although we patiently waited two long hours on Dolo church spire, when both I and my companion descended we were not in a position to solve either of these problems. We, however, thought then, and still think, they were the guns of the Italian fleet which had attacked an Austrian fort. CIVITA VECCHIA, July 22, 1866. Since the departure from this port of the old hospital ship 'Gregeois' about a year ago, no French ship of war had been stationed at Civita Vecchia; but on Wednesday morning the steam-sloop 'Catinat,' 180 men, cast anchor in the harbour, and the commandant immediately on disembarking took the train for Rome and placed himself in communication with the French ambassador. I am not aware whether the Pontifical government had applied for this vessel, or whether the sending it was a spontaneous attention on the part of the French emperor, but, at any rate, its arrival has proved a source of pleasure to His Holiness, as there is no knowing what may happen In troublous times like the present, and it is always good to have a retreat insured. Yesterday it was notified in this port, as well as at Naples, that arrivals from Marseilles would be, until further notice, subjected to a quarantine of fifteen days in consequence of cholera having made its appearance at the latter place. A sailing vessel which arrived from Marseilles in the course of the day had to disembark the merchandise it brought for Civita Vecchia into barges off the lazaretto, where the yellow flag was hoisted over them. This vessel left Marseilles five days before the announcement of the quarantine, while the 'Prince Napoleon' of Valery's Company, passenger and merchandise steamer, which left Marseilles only one day before its announcement, was admitted this morning to free pratique. Few travellers will come here by sea now. MARSEILLES, July 24.