What Forests Give

WHAT IS WOOD?

When some man, picking up the branch of a tree, began to wonder what it was made of, he had got a long, long way from the savage state. He must have realized the great difference between what happened to wood when he chopped it up, or sawed it up, after which it was still wood; and what happened when he set fire to it and it became flame, smoke, and ashes—none of which was at all like what it had been before. He was a modern-minded man, and he opened a door to high adventure which scientists are still pursuing. For years now they have been conducting an exploring expedition as exciting as the one Roy Chapman Andrews led into the Gobi Desert, only it is made with retorts and electric current, instead of camels and motortrucks, and is headed toward a far more remote land than Tibet, a land which is beyond any to be reached through the microscope—that far realm of the atom and the molecule which is hidden in the very structure of wood. To reach this land they are taking wood apart, not with ax or saw or grinding machine or explosive gun, but with chemicals which divide it as no machine on earth can.

These chemist-explorers by a process called hydrolysis—which, reduced to its simplest terms in the case of wood, is treating the wood with a weak solution of sulphuric acid—have extracted a great variety of substances, among which are several sugars which may be converted into ethyl alcohol, aniline used in dyes, furfural, molding powder, and, most important of all, cellulose.

When cellulose is captured by the exploring chemists it is seen to be soft and white like cotton but with particles so much smaller that they feel like grains between the finger and thumb. The discovery of cellulose was part of the answer to the man who first held a stick of wood in his hand and asked himself what it was made of.

The question naturally followed, in what form could this cellulose be put together again and for what could it be used?

There are already more answers to this question than there are leaves to this book—and we have not got them all.

Cellulose, if it had a sign to represent it as the eagle represents our country, might be shown as a horn of plenty—so many things of so many sorts can come out of it. There are guncotton, which is a powerful explosive; smokeless powder; food for cattle. Shoe soles are made from it; poker chips, lemonade straws, long-wearing rugs and carpets, and upholstery goods; materials to cover roofs and walls; substitutes for cotton batting; bags and purses of a leather substitute which no animal ever wore under his fur; lacquers that come from no oriental insect; a waterproof, fireproof, acidproof substance with a high gloss which may be used for anything from telephone receivers to salad bowls.

Besides these, there is a group of things which are produced because it is possible to reduce cellulose to a jelly. The processes by which these things are made, the chemicals that are used, the machines which handle them, all these are as different as can be, but at some stage in their manufacture each one of this group of things is a jelly.

Take for instance Cellophane—as clear as glass, waterproof and dustproof, as pliable as paper and far stronger and more durable. Nothing so perfect has yet been discovered to wrap food in, to protect delicate merchandise, and quite recently as a cheap, unbreakable substitute for window glass.

What can't you make of a jelly which will grow hard and still have a luster like pearl or glass or silk! Just as the wasp showed us how to make paper out of wood, so the silkworm has taught us how to make out of cellulose that soft, glossy, beautiful thread, rayon.

A Frenchman named Chardonnait, who watched the silk worm at work, learned from her how to make rayon. He found how, inside that chemical laboratory which is her body, the worm transforms digested mulberry leaves into a sticky jelly and forces it out through tiny holes called spinnerettes, and how this hardens into slender shining threads.

In making rayon, wood pulp instead of mulberry leaves is converted into an orange-colored jelly, like heavy molasses. It is forced through a platinum nozzle with 40 holes, each 0.002 inch in diameter, into a shining thread. This thread is washed in a spray of warm water, dried in a wind of warm air, wound on bobbins, bleached, and sent to the textile mills to be woven into beautiful cloth. It gives us a fabric that is quite as lovely as silk for as little as we pay for cotton. Just as to make houses out of plywood makes it possible for more of us to have homes of our own, and making paper out of wood makes it possible for all of us to have books, so making rayon out of wood makes shining garments possible for us all.

There can be only as much silk as there are worms to spin it, but there can be as much rayon as we will grow trees from which to make it.

Out of that cellulose jelly is made those long narrow ribbons, those semitransparent bands on which are recorded history as it is being made day by day, the great romances of the past, the quite different dramas of the present, the discoveries of inventors and the great adventures of scientists—the films on which motion pictures are taken. We cannot all go into the Antarctic, but we can see Byrd's airplanes landing there; we can see Picard's gondola go up into the stratosphere and watch Beebe's bathysphere dip down into the sea. We can watch the human heart send the blood pulsing through the arteries. We can watch a malaria germ catch and destroy a red blood corpuscle; we can travel with our eyes to more parts of our world than we could take our bodies to in 80 years of constant traveling, and it seems probable that we will soon be able to look at what happened 50,000,000 years ago to the suns that circle round the shores of the Milky Way—and all because of these films made from that jelly made from cellulose, made from wood grown by the forests.

To have plenty of forests is to have plenty of books and unbreakable windows, and plenty of glistening cloth, and the delight of the moving pictures.

Those scientist-adventurers who have blasted their way into the very composition of wood by a chemical barrage far more destructive than any machine gun could lay down, have found many things beside cellulose. Among them is a strange dull-colored substance which makes up almost one-third the weight of wood. They can look at it and touch it, but until recently they could not tell what it was or what it could do. They call it "lignin."

For 25 years men have been trying to find a use for lignin, as they once tried to find a use for anthracite which they didn't know would burn. Lignin comes, they know, from the cell walls and the spaces between them. It forms in the living cells when they are about to die and become heartwood. Apparently it gives them strength and hardness.

Somewhere in that unexplored jungle, which scientists enter when they take wood apart by chemical means, the scientists knew was the knowledge they needed to make lignin useful. In their search for this knowledge they got down to the actual structure of the lignin molecule and found, quite recently, that the elements of carbon, hydrogen, and oxygen which compose it, are hooked together in a five-sided molecular structure called the "furane ring", and not in the six-sided hydrocarbon ring as they had supposed. This gives the chemists a new place to start from. Already they have found that there are ways to compress lignin into wallboards and floor tiles, ways to get dyestuff from it, and acid for bleaching clothes, and a substance which will act as a binder for roads, and another that can be fed to cattle. The door to the uses of lignin has been opened just a crack. Sometime the chemists will swing it wide.