"But if trees grow so rapidly there," asked Tom, "how is it that there are no woodlands there?"
"Because it is a rainless region. It is a desert simply for a lack of water, and when men build reservoirs up in the mountains and bring water down in irrigating ditches that desert literally blossoms like a rose. The soil is as rich as any down in our valleys and creek low grounds here, and as there is no winter every living thing grows all the year round. At Riverside, for example, you find a luxuriance of growth unmatched anywhere in these mountains. Eucalyptus trees border all the roads, towering to great heights. Back of them are orange and lemon groves and still further back vast vineyards in which the stumps of the vines—for they are cut back to a stump every year, to make them bear—are from four to six inches in diameter, so that they need no stakes to support them as vines do here. Often also there are rows of luxuriant pepper trees flourishing in the middle of the road. In short, you can nowhere on earth except in swamps, find a more luxuriant riot of vegetation than at Riverside. Yet until men made reservoirs and ditches and brought water down there from the mountains the ground that now supports all this splendid growth was as bare as the palm of your hand, and when you drive out of Riverside in any direction, you come instantly to an absolute desert, without even a weed growing on it, the moment you pass beyond the line of irrigating ditches."
"Is there much land of that sort?" asked Jack, "land that is fertile I mean in itself, but is desert because of a lack of water?"
"Millions of acres of it, though much of it has already been redeemed by irrigation. General Sherman once said that when he first crossed the San Joaquin and Sacramento valleys he could have bought the whole of them for twenty-five cents, and in fact would not have given a penny for both. Yet to-day those valleys are the most productive wheat fields in the world, not even excepting Minnesota and the Dakotas. In a single year they have been known to furnish fifty million bushels of wheat for export, after feeding the Pacific coast fat."
"But is there always water to be had for irrigating purposes?" asked Jack, who was becoming intensely interested.
"Practically, yes," the Doctor answered. "That is a country of vast mountain ranges, all the way from the Rockies to the sea, with great valleys and plains lying between. It is almost always raining or snowing in the mountains, and indeed the tops of the higher ranges are nearly always snow clad, even in summer. I remember once crossing the Utah desert, which lies between the Rocky mountains proper and the Wassach range. There is no sand or gravel there, but only a singularly rich soil, barren for lack of rain alone. During the entire trip across we were never for one minute out of sight of either a snow storm or a rain storm some where in the mountains that surround the desert. Obviously enough water falls in the mountains to make of that desert the very garden spot of America when ever men take measures to store the water and bring it down to the desert lands below. The Mormons, who have made a rich farming region in this way out of the desert west of the Wassach range, have already begun doing this on the eastern side in a limited way. At Pleasant Valley they have brought water down from the mountains and made gardens that are a delight to the eye and mind. They grow there the finest black Hamburg grapes in the world. But neither that nor any other of the great deserts can be redeemed entirely until either the government or some great company able to spend money by scores of millions shall undertake the work in a systematic way, selling water rights with every farm. Of course no farmer can provide a water supply for himself from mountains twenty miles away, but if a great company or the government would catch and store the water and sell the right to use it to each farmer, as is done in parts of Southern California, the major part of what used to be called 'the great American desert' would soon become the great American garden. Of course the alkali deserts of Nevada and worse still, the arid, sandy, gravelly, soilless plains of Arizona and New Mexico can never be reclaimed in that way. But the regions that are barren only because they get no rain, can be redeemed and very certainly will be when this country becomes so crowded with population that every acre of arable land will be needed."
"But isn't this country pretty badly crowded already?" asked Tom.
"Crowded? No," answered the Doctor. "It is very sparsely settled instead. This country has a population of only twenty people to the square mile, while Belgium has 529 and England 540 to the square mile. Long before we fill up to any such extent as that all our arid lands that are fit for cultivation will be watered from the mountains, and regions where now even a cactus cannot grow will produce wheat, corn, cattle and fruits in lavish abundance. But I say, boys, we've talked till after eleven o'clock. This will never do; let's get to bed."