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.