And lastly, in order to avoid all recourse to these emergency contrivances, it is ordained that no vessel shall enter any chamber of any locks under its own steam. Nearly all the accidents that happen in locks are due to the vessels being worked independently of the lock authorities when passing through. Captains may be as anxious as possible to avoid mistakes, but there is many a slip possible between an order and its fulfilment. So the lock operators are not going to be responsible for the safety of a vessel which is not entirely under their own control. None will be allowed to negotiate the locks under its own motive-power. A series of electric towing-stations will be set up on the side walls of the locks. When a vessel approaches it will be brought to a standstill outside the locks. Then four of these towing engines will be fastened to it by means of hawsers--two at the stem, in order to draw the vessel into the locks, and two at the stern, to check its speed and bring it to a standstill when necessary. And this control will of course be exercised all through its passage to the upper or lower levels. We should certainly not hear of any accidents in the lock-chambers of the Panama Canal. [Illustration: Gatun Locks, looking South-West, showing North End of the Locks.] It is expected that a vessel will be passed through the three locks at Gatun in about fifty minutes, though some delay may be caused in the approach. On the Atlantic side the water of the canal will be smooth, and the ship will be in some degree sheltered from the winds, so that there should be no difficulty in the approach from that direction. Coming from Lake Gatun to the locks the vessel may experience a little rough water, though there is seldom a great force of wind there, and the lake will be free from currents. As regards the Pacific side, the ocean there fully corresponds with its name. It is always calm, and not the slightest difficulty may be anticipated from either winds or waves or currents.