“‘It is a system of storing water throughout the interior of the country so as to save the precious fluid when the rainfall is excessive. There are many places, great numbers of them, where nature has so formed the ground that the storage of water would be comparatively easy. I have already begun it on my sheep run, and other sheep owners have done the same thing. It is an expensive work, but I believe it will pay in the end.’
“‘There are three places on my land where broad valleys terminate at their lower ends between hills forty or fifty feet high. Now, by building a dam from one of these hills to the other, I can flood any one of these valleys to any depth I choose up to the height of the hills. It was only recently that I finished work at one of these places, and I have gangs of men busy with the other two. For the present I shall make my dams thirty feet high, and this will give me at each of the three places a lake of fresh water with about forty acres of surface area. If I can fill these lakes every winter with water, I think I will have enough to keep my sheep through the dry season, after making liberal allowance for loss by evaporation and in other ways. Of course, such a system of storing water is only practicable where the owner of a place has sufficient capital for the purpose. The poor man, with his small flock of sheep, can hardly undertake it.’
“‘Preliminary surveys have been made in places where it is proposed that the colonial governments should build extensive works for saving water on a grand scale. The government would be repaid, in part at least, by selling the water to private landholders in the same way that water is sold in California, New Mexico, and other parts of the United States. I am confident that you will see a grand system of water storage in full operation in Australia before many years.’”
While on the subject of rainfall, Harry asked Ned if he knew where the heaviest annual rainfall in the world was.
Ned said he did not know, but he thought that Dr. Whitney might be able to inform them.
The question was appealed to the doctor, who paused a moment, and then said that “what might be considered a heavy rain in one place would be a light one in another. In Great Britain, if an inch of rain fell in a day it was considered a heavy rain; but in many parts of the Highlands of Scotland three inches not infrequently fall in one day. Once in the isle of Skye twelve inches of rain fell in thirteen hours, and rainfalls of five and seven inches are not uncommon. Thirty inches of rain fell in twenty-four hours at Geneva, in Switzerland, thirty-three inches at Gibraltar in twenty-six hours, and twenty-four inches in a single night on the hills near Bombay.
“The heaviest annual rainfall on the globe,” continued the doctor, “was on the Khasia Hills, in India, where six hundred inches, or fifty feet, fell in a twelvemonth. Just think of it; a depth of fifty feet of water yearly, and of this amount five hundred inches fell in seven months, during the southwest monsoons.”
“How do they account for such heavy rains?” Ned asked.
“It is accounted for,” the doctor replied, “by the abruptness of the mountains which face the Bay of Bengal, from which they are separated by low swamps and marshes. The winds arrive among the hills heavily charged with the vapor they have absorbed from the wide expanse of the Indian Ocean. When they strike the hills and are forced up to a higher elevation, they give out their moisture with great rapidity, and the rain falls in torrents. As soon as the clouds have crossed the mountains the rain diminishes very much. Twenty miles further inland it drops from six hundred to two hundred inches annually, and thirty miles further inland it is only one hundred inches. The same conditions prevail to a certain extent in Australia. The mountain chains are near the coast. On the side next the ocean there is a liberal rainfall, but on the other side, towards the interior, the rainfall is light. As the clouds charged with vapor come from the sea to the mountains they yield their moisture freely, but, after passing the mountains, they have little left to yield.”
The burster died away along in the evening, and, though the streets were wet in many places, our friends went out for a stroll. During their walk their attention was naturally drawn to the sky, which was now bright with stars. Naturally, their conversation turned to the difference between the night skies of the Northern and Southern Hemispheres, which had not escaped their observation during their voyage from the east coast of Africa down to the Equator, and thence in the Southern Ocean. On this subject Harry wrote at one time in his journal as follows:—