Through these thousand miles of cañon, more than one fifth of which is the Grand Cañon, the river has a fall of about five thousand feet, unevenly divided. There are long stretches of quiet water, but in the Lodore, Cataract, Marble, and Grand Cañons are numerous and turbulent currents flowing amid masses of wild, rocky débris. There are about five hundred bad rapids and many others of lesser power. Most of these rapids are caused by rock-jams--dams formed by masses of rocky débris that have fallen from the walls above or have been swept into the main cañon by tributary streams. A few rapids are caused by ribs of hard, resistant rock that have not been worn down to the level of the softer rock. The cañon was discovered by Spaniards in 1540. A government expedition visited it in 1859. The report of this expedition, printed in 1861, is accompanied with a picture of an ideal cañon. It is shown as narrow, with appallingly high vertical walls. Lieutenant Ives, who was in charge, thus closes his account:-- Ours has been the first and will doubtless be the last party of Whites to visit this profitless location. It seems intended by Nature that the Colorado River, along the greater portion of its lonely and majestic way, shall be forever unvisited and undisturbed. Ten years later Major John W. Powell explored the series of cañons from end to end. Hundreds of expeditions that have attempted to go through them have failed. Of the half-dozen that succeeded, one was organized and conducted by Julius F. Stone, a manufacturer of Columbus, Ohio. "Why," I asked Mr. Stone, "did you take the hazard and endure the acute hardship of this expedition?" His reply was:-- To photograph consecutively the entire cañon system of the Green and Colorado Rivers, which, so far as the upper cañons are concerned, had not yet been done. We also wished to determine the accuracy of some statements heretofore made which seemed reasonably open to question. Mr. Stone went all the way through the cañon, took hundreds of photographs, and made numerous measurements. He made a thorough study of this cañon, added greatly to our knowledge of it, and corrected a number of misconceptions concerning it.