Master Lewis had allowed the boys to have a day to themselves in each of the principal places where they had stopped. If one of them wished to make an excursion on that day to some neighboring place, the good teacher made some careful arrangement for that one to do so. He was very careful about all matters of this kind, without really seeming to distrust the boys' judgment in their efforts to look out for themselves. A coach-driver, a traveller, a valet-de-place, or some person was usually employed to have an eye on the member of the Class who was allowed to make a tour to a strange place alone. The boys, with the exception of Tommy Toby, were given a day to go where they liked in Paris. Master Lewis did not dare to allow Tommy this privilege, after his misadventure in England. The Wynns visited the Palace of the Institute; Frank Gray, the Grand Opera House. "I would like to go to the river this morning," said Tommy, "and sail on the ---- queer boats there." "The flies, or water-omnibuses?" said Master Lewis. "I will go with you." Tommy looked surprised and hardly seemed pleased, not that he did not generally like Master Lewis's company, but because it looked to him like a restraint upon his freedom. But the good teacher took his hat and cane, and Tommy did not express any displeasure in words. The two went to a splendid stone bridge called the Pont d'Jena, over the Seine. Compared with the Mississippi, the Ohio, or the St. Lawrence, the Seine is but a small stream. The river is lined with solid stone-work on each side, and its banks are shaded with trees. It is filled with queer crafts, and a multitude of families live on the barges that convey wood, coal, and certain kinds of merchandise from place to place. As Master Lewis and Tommy were standing on the bridge, watching the sloops as they lowered their masts to pass under, an astonishing sight met Tommy's eyes. It was a great boat, like a steamer, but without screw or paddles, swiftly passing up the river by means of a chain which rose out of the water at the bows, ran along the deck, turned around wheels which seemed to be worked by an engine, and then slipped overboard at the stern. "How far can that boat go on in that way?" asked Tommy. "The chain by which the boat is carried forward," said Master Lewis, "is _one hundred miles long_." Master Lewis and Tommy passed some hours among the queer crafts on the river, taking passages here and there on the flies or water-omnibuses. "Were you afraid to trust me alone this morning?" asked Tommy, on their return. "Well, yes." "Did you think I could not speak French well enough to go out alone?" "Your French might not be very well understood here." "I think I can talk simple French, such as servants could understand very well."