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position desired, the drum operating the hoisting rope was brought into motion and the load was lowered to the dam.

The granite blocks and the larger limestone rubble stones were handled by immense tong-like grips. The cement and sand were loaded into cages, transported to the place of construction, and there dumped on the dam. The cement mortar was made at the place where it was to be used, and the blocks of masonry were placed where needed by crane derricks shown in Pl. IV, B.

*A wire rope one-half inch in diameter was used in connection with the cable and saddle to prevent excessive vibration of the operating ropes. On this rope there were buttons which increased in size from the tower to the west. The hoisting rope was supported at different points by carriers which rested, when the saddle was stationary, on the main cable. This carrier consisted essentially of two parallel bars, between which and near the lower end a small pulley was supported to carry the hoisting rope. A series of slots were arranged in the upper part of the carriers through which some of the buttons could pass. When near the east tower the saddle supported all of the carriers on a horn. In moving from the tower to the west, the smaller button passed through all of the carriers except the last, which it took off the horn; the second button passed through all of the remaining slots except that in the second carrier, which it pulled off the horn; etc. The carriers wore thus stripped off the horn by the buttons and rested on the main cable, affording a groove or support for the hoisting rope and reducing its vibration.

LEAK UNDER HEAD GATE.

On May 30, 1893, the water from the lake cut under the east bulkhead and undermined the proposed foundation of the power house. It entered a seam in the limestone slightly above the point indicated at B in fig. 5, about 90 feet from the dam. From this point the course of the water was at an angle of about 30 degrees to the axis of the river to the left, and it also took a downward- course and passed about 25 feet under the foundation of the head-gate masonry. A view of the power-house foundation a few days before the break is given in Pl. VI, A. The water issued from the west wall of the proposed power-house foundation and soon wrecked it. The general course of the water was from a point near the east end of the head-gate masonry diagonally across the foundation to the point of exit.

A cofferdam about 125 feet long was constructed of framework, with dirt and hay as fillers, from a point on the shore above the entrance to the crevice to a point near the end of the dam. This effectually cut off the water from the proposed forebay, and the work of repair commenced. As originally designed, the head-gate masonry contemplated 9 large pipes, but only 7 were put in.

The head-gate masonry cracked about 40 feet from the end of the