"Oh; this canal was not made as large as this when it was first built. It has been enlarged since. But you know that we do not do all our digging now by hand. Steam shovels do the work for us. That gives us a great advantage over the day laborer with his pick and shovel." "What strikes me as most noticeable," said Mr. Greenleaf, "is the number of vessels waiting on both sides of the lock. What causes such a crowd to-day, particularly?" "This is no unusual number," replied Mr. Towne. "You do not realize what a traffic there is on the great lakes. It is stated that the tonnage passing through this canal is greater than that through any other strait on the face of the globe. This growth is very recent and very rapid." "But what causes the traffic and where are all the vessels going?" asked the missionary. "The great bulk of the freight," answered the younger man, "is grain from the Northwest, and iron, copper, coal, and lumber, now being obtained in vast quantities south of Lake Superior. So long as the steamboats can carry freight more cheaply than the steam cars, grain and ores will take this route. Sometime we shall have canals large enough for ocean steamers, which will connect the great lakes with the Atlantic Ocean. Then we can load our freight at Chicago or Duluth and not change it until it is unloaded at some English or European port." The next day, as the steamboat was lying at the wharf at Detroit, conversation was turned to the great ferryboats plying across the river. "I notice great changes in the steam ferries, since last I crossed the North River at New York," remarked Mr. Greenleaf. "Yes," was the reply, "but you see only improvements. The ferryboats are larger and you might almost say clumsier; that is all." "I do not think so," returned the missionary. "There must be some new invention to enable entire trains, with cars filled with passengers, to be carried across such a river as this." "Of course," said his nephew, "the boat must be strong and large. However, the ferry docks have been improved. Now, when the boat is fastened, the wharf can be raised and lowered, until it is exactly on the level of the boat. Then not only passengers, but wagons and steam cars can pass from one to the other almost without knowledge of the change." "How far have these cars come that I see on the ferry?" "That," said the drummer, "is one of the through trains from Montreal to Chicago. The ferryboat next beyond, going the other way, bears a train containing cars bound for New York and Boston." "Well, well! This is convenient," said the missionary. "The passengers are saved much trouble by not being required to gather up all their traveling bundles, leave the cars for the boat, and the boat for a new set of cars. We should have thought this a great gain, forty years ago."