Canvas coated or impregnated with such soluble cellulose gives us new flexible and durable fabrics that have other advantages over leather besides being cheaper and more abundant. Without such material for curtains and cushions the automobile business would have been sorely hampered. It promises to provide us with a book binding that will not crumble to powder in the course of twenty years. Linen collars may be water-proofed and possibly Dame Fashion--being a fickle lady--may some day relent and let us wear such sanitary and economical neckwear. For shoes, purses, belts and the like the cellulose varnish or veneer is usually colored and stamped to resemble the grain of any kind of leather desired, even snake or alligator. If instead of dissolving the cellulose nitrate and spreading it on fabric we combine it with camphor we get celluloid, a plastic solid capable of innumerable applications. But that is another story and must be reserved for the next chapter. But before leaving the subject of cellulose proper I must refer back again to its chief source, wood. We inherited from the Indians a well-wooded continent. But the pioneer carried an ax on his shoulder and began using it immediately. For three hundred years the trees have been cut down faster than they could grow, first to clear the land, next for fuel, then for lumber and lastly for paper. Consequently we are within sight of a shortage of wood as we are of coal and oil. But the coal and oil are irrecoverable while the wood may be regrown, though it would require another three hundred years and more to grow some of the trees we have cut down. For fuel a pound of coal is about equal to two pounds of wood, and a pound of gasoline to three pounds of wood in heating value, so there would be a great loss in efficiency and economy if the world had to go back to a wood basis. But when that time shall come, as, of course, it must come some time, the wood will doubtless not be burned in its natural state but will be converted into hydrogen and carbon monoxide in a gas producer or will be distilled in closed ovens giving charcoal and gas and saving the by-products, the tar and acid liquors. As it is now the lumberman wastes two-thirds of every tree he cuts down. The rest is left in the forest as stump and tops or thrown out at the mill as sawdust and slabs. The slabs and other scraps may be used as fuel or worked up into small wood articles like laths and clothes-pins. The sawdust is burned or left to rot. But it is possible, although it may not be profitable, to save all this waste.