is to be developed. In a single tractthe Lolo Reserve in Montana-of 1,211,000 acres, there are some 300,000 acres which have been carelessly lumbered and burned over, with the result that there is not a seed tree left for natural reproduction. At the cost of a few cents an acre this great area would have naturally reforested itself. As it stands it is hopeless and must at some future time be planted to trees. That the destruction. of our mountain forests is a most serious matter and an evil that must be remedied is seen in a parallel case in the French forests. The destruction of forests in the Alps ruined one of the most fertile areas of Southern France and this has cost the French government over $35,000,000 for correction and replanting, with much more yet to be done.

"We know," said Forester Pinchot, in speaking of the relation of western forests to water supply, "that forests do conserve moisture and equalize and regulate stream flow. We know from the records of the past in other countries that where watersheds have been denuded of their trees, rivers have dried up. We know that reforestation of some of these areas has restored the rivers. We have here great treeless areas which can be successfully aforested and we do not know but that by this process we can create rivers."

The Forest Service is preparing to clothe the barren sandhill country of Nebraska with jack-pine and other trees, and for this purpose a big nursery has been established there. For a long time these sand hills were thought to be useless and it was assumed that trees would grow only in the valleys. Recent experiments have shown that pine will grow on the sand hills proper. A million acres

would be a low estimate of the otherwise nearly waste land in Nebraska that can be profitably planted to trees. The service has six nurseries with an annual productive capacity of about 8,000,000 trees, and is preparing to establish additional ones. The gathering of seed for this planting is quite an item, but in this work the squirrels are valuable assistants. Cones from squirrel hoards are usually of good quality, for they are gathered by the rodents from the tree tops and are usually full of plump seeds. Plans are being laid for the planting of vast treeless areas in Oklahoma, Indian Territory, Kansas, Colorado, Texas and New Mexico. In some of this section it will be government planting, in other parts co-operative planting. Until recently it was generally believed, and is yet by many settlers, that on the high table lands of the southwest no kind of forest tree could be grown without irrigation. It is now known that good tillage for the first three years can be substituted for artificial watering and that with such treatment forest plantations will thrive.

All in all, the question of American forestry is a mighty one and the branch of forest planting is a big part of it. At the present moment the preservation of existing forests and the fostering of reproduction by natural seeding methods is the most important feature; but as the country settles up, tree planting will become more and more necessary and with the utmost activity from this time forward, through both co-operative and government forest planting it will be next to impossible to keep pace with the actual demand of the country for forest creation.

When it is considered that the cool crust of the planet on which we dwell is thinner, relatively to size, than the shell of an egg, and that at a depth of only twenty-five miles-a distance less than from Philadelphia to Trenton-all substances are molten, the temperature being something like 10,000 degrees, it seems absurd that we should indulge anxiety about an available heat supply for the future. As will presently be shown, there are places where the shell of the globe is very much thinner, and where the hot core is so near the surface

that, merely for experimental purposes, it would be worth while to spend $50,000 in sinking two pipes to a depth of twelve thousand feet. A connection having been established, in a manner presently to be described, between the lower ends of the pipe, an inexhaustible supply of heat could be fetched to the surface.

To make this clear, it should be explained that, going down into the depths' of the earth, the temperature rises usually about one degree for every sixty feet. Thus, if two such pipes, fifty feet apart, were sunk twelve thousand feet, the temperature at their lower ends would be considerably above the boiling point of water. The next thing would be to establish a connection between the conduits by simultaneously exploding heavy charges of dynamite at their bottoms. By this means the rocks would be extensively shattered, and it is likely-especially if the process were repeated again and again-that fissures affording the requi.. site communication would be opened up.

Having accomplished so much, suppose that a small stream of water, diverted from a river, perhaps, were to be turned into one of the pipes. Its flow, filling the crevices of the shattered rocks more than two miles below, would be converted into steam, as is a gigantic water-heater, which would be forced