The requisite most difficult to obtain, in sufficient amount, was unskilled labor. An attempt was made to get five hundred peons from central Mexico; but it did not succeed, and Mr. Cory was finally compelled to mobilize all the Indian tribes in that part of the Southwest--Pimas, Papagoes, Maricopas and Yumas from Arizona and Cocopahs and Diegueños from Mexico. These Indians fraternized and got along together amicably, and constituted with their families a separate camp of about two thousand people. The rest of the laborers were Mexicans from the vicinity, and drifting adventurers from all parts of the United States who were attracted to the place by the novelty of the work and the publicity given to it in the newspapers. Arrangements were made with the Mexican authorities to put the whole region under martial law and to send a force of rurales with a military commandant to police the camps. [Illustration: Situation in June, 1906 (whole river going into Salton Sink)] Active work began on the 6th of August, 1906, when the summer flood had fallen enough to reduce the flow through the crevasse to about 24,000 cubic feet per second. By that time the receding water had left exposed extensive sand-bars on both sides of the river, which narrowed the channel to 600 or 700 feet, and President Randolph’s plan was to dam this channel sufficiently to throw all or most of the water through the by-pass and the Rockwood head-gate, and then permanently to close the break. As it was deemed essential to blanket the bed of the river with a woven brush-mattress, to prevent bottom erosion and to make a foundation for the rock, two shifts of men were set at this work. In twenty days and nights, they constructed, with baling-wire, steel cable and two thousand cords of brush, about 13,000 square feet of mattress, which was enough to cover the bed of the river from shore to shore with a double thickness of blanketing about one hundred feet in width. When this covering had been completed and sunk, a railway trestle ten feet wide was built across the crevasse, and on the 14th of September work-trains of “battleships” began running across it and dumping rock on to the mattress at the bottom of the stream. Meanwhile, the by-pass to the Rockwood head-gate was completed and enlarged, and in less than two weeks the dam was high enough to close the crevasse in part and thus divert water through the by-pass and gate. On the 10th of October, nearly 13,000 cubic feet of water per second was passing through the gate, while only one-tenth of that amount was flowing over the dam. The gate, however, under the pressure to which it was subjected, both by the water and by great masses of accumulated driftwood, began to show signs of weakness, and at two o’clock on the following day two-thirds of it gave way, went out, and floated down stream. The by-pass then became the main river, while the top of the diversion dam was left practically dry.