But the time has come when we can no longer continue this waste without interfering with future development. Some of the resources have been so exhausted that a few years will see the end of their use in large commercial quantities. Others, such as coal and iron, will last much longer, but when they are gone they can never be replaced; and so far as we can now foresee, the country will cease to prosper when they can no longer be had for use in manufacturing. The length of time they will last at the present rate of use can be easily calculated. It is a long time for us to look forward, for it is longer than the lifetime of any man now living, or of his children, but it is within the life of his grandchildren, and that is a very short time in the history of a nation.

It may be said that while other nations have passed into decay, none has ever exhausted its resources so early in its history, and surely this great rich nation can not so soon face actual need. But we must remember that no other nation has ever used its resources as we have used ours. We are using in years what other nations have used in centuries.

It is not possible now, it probably never will be possible, to use every particle of a resource. This would be too expensive, would mean a labor cost far beyond the value of the thing saved.

In the beginning, as we have shown, the vast wastes were not wanton, but absolutely necessary, and we have not yet reached the point where we can afford to use the low-grade ores, to use all lumber waste and to practise many other economies that may sometime become necessary. But in the case of the forests we should provide enough trees for use in coming years, and in the case of all minerals, the refuse should be left in such condition that it can easily be ready for possible future use.

If conservation meant leaving our resources untouched, and checking development in order that there might be an abundance for future generations, it would be both an unwise and unacceptable policy; but it must be thoroughly understood that this is not what is desired.

Conservation does not mean the locking up of our resources, nor a hindrance to real progress in any direction. It means only wise, careful use.

It does not mean that we shall cease to cut our timber, but it does mean that we shall not waste two-thirds of all that is cut, as we are doing at present. It means, too, that we shall take better care of articles manufactured from it, and most of all, it means that, when a tree is cut down another shall, whenever possible, be planted in its stead to provide for the needs of the future.

It means that we shall not allow the farms of our country to lose five hundred million dollars in value every year by letting the rich top-soil drain off into our rivers, because we have cut away the trees whose roots held the soil in place. It also means that we shall not steadily rob the land of the elements that would produce good crops, and put nothing back into the soil.

It means that we shall not kill the birds that destroy harmful insects and thus invite the insects to destroy the crops that we have cultivated with such care.

It does not mean that we shall let our mines of coal and iron lie unused, as the miser does his gold, but that we shall, while taking what we need, leave as little waste in the mine as possible, and shall use what we take in the most economical way. This means a saving of money to the user, as well as a conservation of resources. It means, too, that we shall not allow our water-power to remain unused, while we burn millions of tons of coal in doing the work that water-power would do better.