Where were the Spanish ironclads going? On Sunday morning, April 9th, Trinity Church was crowded with worshipers. The venerable Bishop of New York was present, and was to deliver the sermon. His erect, stately form, clad in the flowing robes of his office, had just appeared in the pulpit, and he had spoken the words of his text, when a commotion in the rear of the church caused him to stop and look up, wondering at the unseemly interruption. A soldier emerged from the crowd, and, making his way to the Astor pew, handed a letter to Mr. John Jacob Astor. The ruddy face of that gentleman blanched as he read its contents. Then he rose, walked to the pulpit, and handed the missive to the bishop. A dead silence prevailed--at last broken by these simple words: "Brethren, the war-vessels of the public enemy have appeared off our Harbor. Let us pray." A deep, heart-felt Amen responded to the appeal made in eloquent, though faltering, tones; and then, quiet and orderly, the congregation left the temple. It was fitting that such a prayer should be the last ever offered in a sanctuary of which, but a few days later, only a heap of smoking ruins remained. The same news had been forwarded to the other churches, and the congregations, dismissed, had gathered in front of the great bulletin-boards which had been erected in the various parts of the city. In huge letters were the words: "A large steamer, showing Spanish flag, sighted off Barnegat." Shortly afterwards came another dispatch: "The United States frigate 'Franklin' has been signaled off Fire Island." Then another dispatch: "The Spanish steamer has gone to the eastward." And then, three hours later: "Heavy firing has been heard from the south and east." II. THE BATTLE OF FIRE ISLAND. The "Franklin," on leaving Fire Island, where she had communication with the shore, stood to the westward. At 3 p.m. the mast-head look-out reported a large steamer on the port bow. As is customary on vessels at sea, the "Franklin" showed no colors; the stranger displayed a flag which could not be made out. On the poop-deck of the "Franklin" were Admiral Rowan, Captain Greer, commanding the ship, and the executive officer, Lieutenant-Commander Jewell. "Mast-head, there! can you make out her colors yet?" hailed the latter. "No, sir." "Take your glass and go aloft, Mr. Rodgers," said Admiral Rowan to his aid; "perhaps you can see better." The officer rapidly ascended the rigging to the foretopmast cross-trees. "It is the English flag, sir!" he shouted. "Hoist English colors, Captain," said the admiral, quietly; "and bend on our own, ready to go up." The red cross of St. George, the British man-of-war flag, rose slowly to the peak. The stranger was seen to alter her course, and head for the "Franklin." The admiral turned to Captain Greer and nodded. The latter gave an order to a midshipman standing near. Rat-tat--rat-tat--rat-tat-tat-tat!