Skylining. Showing How the Aerial Tramway Works, and, Inset, a Huge Log Crossing a Ravine
More recently, "high-wheelers" have been applied, in which the log is picked up between the wheels of a two-wheeled skeleton trailer and towed by the tractor. This is particularly effective where there are many stumps or bowlders, since the logs are carried high enough to clear such ground obstacles. In the swamps, where there is mud all the way out, floats or skids, made on the ground from smaller logs, are towed out by tractor. Even the donkey engine, which in some lumber camps superseded the team, in turn has been virtually put out of business by the portable power plant, with its winches filled with steel cable, and its ability to move itself anywhere. Fire danger from the old-time "donk" also is removed. Other mills, in Montana and California, similarly situated on the downhill sides of their forests, use chutes or flumes. Running sixty miles from mountain mill to railroad, in California is the longest lumber flume in the world. It handles cut timbers by a stream of water, the lumber being halted at any loading station by ropes and snubbing posts.
One large lumber company has now in process of construction, at a cost of $250,000, an incline railroad down one side of a deep gorge and up the other, to be operated by electricity. This installation will make available approximately half a billion feet of lumber, sufficient to occupy this mill for the next eighteen years. The distance is about ten miles. One 200,000-pound electric hoist will drop the lumber-laden cars into the canyon, where another similar hoist will lift them out. The cars will slide down and climb out at a virtually uniform speed of 600 feet a minute.
Lumbermen agree that profit in their in-
