runaway ship would crash, not into the gates that hold back the water, but a pair of massive "Guard gates," placed below the others for this very purpose.
"The lock gates will be steel structures seven feet thick, sixty-five feet long, and from forty-seven to eighty-two high. They will weigh from three hundred
A BIRD'S-EYE VIEW OF ONE OF THE NINETY-TWO PANAMA
"BULL-WHEELS."
This wheel was invented by Mr. Edward Schildhauer of the Isthmian Canal Commission. The wheel revolves horizontally and thrusts out from the side of each lock-wall a long steel arm that opens and closes one of the huge lock-gates. These gates are of the "miter" pattern, so called because, when closed, they make a blunt wedge pointing up-stream, like the slope of a bishop's miter. Observe the curved and hollowed recesses in the lock-walls into which the open gates fold back, like the blades of a knife into the handle. There are, of course, two "bull-wheels"; one for each of the gates.
to six hundred tons each. Ninety-two leaves will be required for the entire Canal, the total weighing fifty-seven thousand tons. Intermediate gates will be used in the locks, in order to save water and time, if desired, in locking small vessels through, the gates being so placed as to divide the locks into chambers six hundred and four hundred feet long, respectively. Ninety-five per
