Before war conditions put a wall around everything, seeing the Canal was one of the pleasantest and easiest of touring tasks. All was in plain view, or could readily be found by asking, and most of the men on duty thought it a pleasure to answer questions. Of camera fiends and sketchers and notebook makers there were aplenty. But the war stopped all that for a time. Anybody could look at the Canal from almost any point along its survey, but the locks and docks were strictly private affairs. There are statistics in abundance to be had for the asking concerning the Big Ditch. Experts take pleasure in supplying us with entertainment by compiling and translating figures into interesting statements. For instance, enough excavating was done on the Canal to dig a tunnel fourteen feet in diameter through the center of the earth, eight thousand miles of boring. It takes a little time to comprehend the meaning of a tunnel from Valparaiso, Chile, to Peking, China, or straight through from the north pole to the southern tip of the world. Enough concrete was used to build a wall four feet thick and twenty-five feet high clear around the State of Delaware. Probably by walking the two hundred and sixty-six miles represented by this wall, one might understand the amount of concrete involved in the Canal construction. The enormous size of the locks can only be understood by walking their length through the underground tunnels and passageways in which is located the marvelous machinery of their operation. To stand on the floor of a dry lock and look up at a lock gate eighty feet high, seven feet thick and sixty-five feet wide is an impressive experience, but to see a pair of such gates swing open and shut at the touch of the finger is something to be remembered. The emergency dams look like a steel girder bridge, which, indeed, they are, and provide against accidents by as ingenious a piece of mechanism as the entire system affords. Enormous iron chains with hydraulic springs are stretched across the entrance to the locks to stop any reckless ship which might otherwise strike the gates. The Gatun Dam alone may be classed as one of the world's greatest achievements. The builders of the Canal may be pardoned for taking pride in the fact that the entire construction cost, down to the present day--three years after the opening of the Canal--is still within the original estimate of $375,000,000, which figure included the $40,000,000 paid to the French for the work of the earlier construction. This means that the cost of the Canal was a little less than four dollars apiece for every inhabitant of the United States. The national prestige alone gained by the successful completion of the work has repaid this four-dollar investment many times over. Before the European war $400,000,000 seemed like a good deal of money. To-day we think of it as a very small sum.