"All right; you know what you are about every time, and it is best to keep your mouth shut, in ease you should not succeed as well as you expect. I have a dozen rather small jack-screws, and I will have all of them put on the deck of the gundalow," added Mr. Miker, as he ordered his men to bring them from a shanty where they were kept under lock and key. "I will see that everything is brought back again before morning," said Dory, as he stepped into his boat, and gave the order to return to the Sylph. It was now nearly ten o'clock on as beautiful an evening as ever gladdened the heart of any night wanderers. The full moon gave an abundance of light, and the operations of the students could be as readily conducted as in the day-time. Everything that would be needed, with the exception of a few coils of rope, was on board of the gundalow. A party was sent to the shops for them; and when these necessary articles were obtained, the fasts were cast off, and the steamer stood up to the quarries. The gundalow had been so often towed by the Sylph, that the business was perfectly understood. In a few moments more she was made fast to the steamer by the double tow-lines, so that the awkward craft could be steered even around a corner without any difficulty. Will Orwell, the second officer, was detailed to take charge of a party of six on board of the tow. But before the steamer got under way again, Captain Dornwood called all hands together on the forward deck. "Now we shall know what sort of a racket this is going to be," said Dick Halifax, as they hastened to the place of meeting. "No, you won't," replied Dick Short, to whom the remark was addressed. "You won't know anything at all about it until we come to the work to be done." "Why don't he tell us what we are to do?" asked Dick. "I should like to know something about it." "It was a trick of Captain Gildrock to keep his business to himself, and Dory takes after him. The principal thinks the fellows can obey orders better when they don't know what is coming than they can when they understand all about it. Every fellow thinks he knows best how to do almost anything." "I don't know but he is right. I never saw a horse tumble down in the street, but every one of the crowd around him wanted to boss the job of getting him on his feet again," added Dick. "I have called you together, fellows, to say that it will be necessary to keep as still as possible on the expedition of to-night;" said Captain Dornwood, when the ship's company had all gathered on the forward deck. "I don't know that a noise would defeat our plans, but I am very much afraid it would cause us some trouble. I don't believe in any yelling when we are on duty, but I fear it would make mischief to-night. Please to observe this request in the strictest possible manner." "Where are we going, Captain Dornwood?" asked Bark Duxbury, one of the new students.