It's a fact. Roots do split rocks. Hundreds of times I've been in the cracks of rocks that were split in that way. I mean right when the splitting was going on. This happened oftenest where trees grew on the stony flanks of mountains. Seeds of the pines, say, dropped in crevices by the wind, sprout in the soil they find there, and then, as these shoots grow up into trees, the enlarged roots, in their search for more soil, thrust themselves deeper and deeper into the original lodging-place, and so split even big rocks. The tap-roots do the heaviest part of this pioneer work. After the older and larger roots have broken up the rock, the smaller roots and fibres, feeling their way about among the stones, enter the smaller openings and by their growth divide the rock again and again. But it's a lot of hard work for little return, so far as these early settlers are concerned; just a bare living. All these rock fragments, in the course of the years, become soil, but the amount of decay is small in the lifetime of the tree that does the breaking. A root, as you doubtless know, tapers. This enables it to enter a rock crevice like a wedge. As it pushes its way in farther and farther it is growing bigger and bigger, and it is this steady pressure that breaks the rock. Even the tiny root of a bean grows with a force of several pounds, and the power exerted by the growth of big roots is something tremendous. At Amherst Agricultural College, one time, they harnessed up a squash to see how hard it could push by growing. From a force of sixty pounds, when it was a mere baby, what do you suppose its push amounted to when it had reached full squashhood in October? Nearly 5,000 pounds; over two tons! [Illustration: HOW A LITTLE ROOT SPLIT A GRANITE BLOCK The little winged seed from which this pine-tree grew was carried by the wind one day into a tiny crack in that big granite block. As the treelet grew the tap root split the rock, penetrated to the earth below and fed the trunk until it became, as you see, a tree 40 feet high and 18 inches in diameter!] But don't think because roots can and do split rocks, if need be, that they go about looking for such hard work. On the contrary. In travelling through the soil they always choose the easiest route, the softest spots. They use their brains as well as their muscles, and what they do with these brains is almost unbelievable. Yet the roots are such modest, retiring folks, always hiding, that it was a long time before the wise men--the science people--found out what all they do. It took a lot of science people and the wisest--including the great Darwin--to get the story, and they haven't got it all yet, as you will see. It was Darwin who first thought of having Mr. Root write out his autobiography--or part of it--the story of his travels; for he does travel, not only forward--as everybody knows--but around and around. A regular globe-trotter! [Illustration: WHY BABY PLANTS BACK INTO THE WORLD