As soon as the vessel starts on its transit of the canal, the Captain of the Port at the point of entrance telephones its starting to the other stations along the course. As the vessel arrives and departs from each of these points, the fact is telephoned along the line, so that there is exact knowledge at each station all the time of the status of traffic, and complete co-operation from the several points of control. The transit of the canal requires about ten hours, of which approximately three hours are spent in the locks. In the sea-level channels and Gaillard (formerly “Culebra”) Cut the speed of vessels is limited to six knots; through Gatun Lake they may make ten, twelve and fifteen knots, according to the width of the channel. A vessel may clear from the canal port at which it enters and, after passing through the last of the locks, put direct to sea without further stop. The handling of a vessel all through the canal, except in the locks, is essentially the same as its handling through any charted channel where observance of signals, ranges and turns is necessary. The canal channel throughout is very accurately charted, fully equipped with aids to navigation, and governed by explicit rules with which the pilots, of course, are thoroughly familiar. In the locks, the vessel is under the control of the lock-operating force. As the vessel approaches the locks, the operator in charge at the control house indicates by an electrically operated signal at the outer end of the approach wall if the vessel shall enter the locks and, if so, on which side; or if it shall keep back or moor alongside the approach wall. If everything is ready for the transit of the locks, the vessel approaches the center approach wall, which is a pier extending about a thousand feet from the locks proper, lines are thrown out, and connections are made with the electric towing locomotives on the approach wall. The vessel then moves forward slowly until it is in the entrance chamber, when lines are thrown out on the other side and connections are made with towing locomotives on the side wall. Six locomotives are used for the larger vessels, three on each wall of the lock chamber. Two keep forward of the vessel, pulling and holding her head to the center of the chamber; two aft, holding the vessel in check; and two slightly forward of amidships, which do most of the towing of the vessel through the chamber. The locomotives are powerful affairs, secured against slipping by the engagement of cogs with a rack running along the center of the track, and equipped with a slip drum and towing windlass, which allow the prompt paying out and taking in of hawser as required. No trouble has been experienced in maintaining absolute control over the vessels.