Page:Popular Science Monthly Volume 27.djvu/76

64 that it is combustible and evolves a large amount of beat in burning, and that this heat can be set free at any time and be readily converted into mechanical, chemical, electrical, and other forms of power. As an illustration of the great amount of energy contained in coal, it is well known to scientific men that each piece of it contains sufficient stored-up power to lift its own weight twenty-three hundred miles in height, or twenty-three hundred times its own weight a mile high. The only other common natural substances to be compared with it in this respect are wood and petroleum, and our stores of these are very small. It is by the expenditure of the energy contained in coal that comparatively valueless iron-ore is converted into valuable iron.

It has not been by the mere existence of large quantities of coal in this country, nor entirely by the sale of coal to foreign nations, that so much of our wealth has been obtained, but largely by the circumstance that we were the first nation to apply coal to industrial purposes on a large scale and in a great variety of ways. Other nations also possessing coal, perceiving the great success of this method, followed our example, have overtaken us, and have now rendered it increasingly difficult year by year for us to maintain our position as manufacturers.

As also large quantities of coal, petroleum, and inflammable gas are continually being discovered and utilized in other countries, and it is known that the United States of America alone contain nearly forty times as much coal as our entire stock, the time can not be very far distant when our chances of maintaining even our present position among nations by means of our coal will be considerably less than at present. It would be wise, therefore, boldly to face this serious prospect, and consider by what means our national prosperity can be maintained as our coal diminishes in quantity and increases in price, especially as our population is continually increasing and has to purchase greater supplies of foreign food.

There does exist another and inexhaustible source of wealth and progress, viz., new knowledge obtainable by means of scientific research. It is upon such knowledge, gained by experiments made to examine natural forces and substances, that we must sooner or later depend as a fundamental source of national prosperity. As fast as this knowledge is evolved by discoverers, it is applied in more immediately practical forms by numerous inventors, and then manufacturers and men of business use those practical realities in the production of wealth. This has been the order of events in the past and will be in the future; this was the way in which we got wealth out of coal. Persons of narrow views on the subject will consider the above proposition vague and unpractical; but this order of things is a great fact and unavoidable. We are the servants of Nature, and have no choice in the matter; we might as well hope to live without food as expect to advance in civilization without the aid of new knowledge.