Agriculture, enlightened by modern chemistry, has brought to light the special importance of the sun in promoting the activity of vegetation, and producing combinations of substances not to be attained by any action except that of the sun. M. Georges Ville, a professor at the Museum of Natural History in Paris, states, as the result of numerous experiments, that the activity imparted to vegetable production by the sun is truly miraculous. No chemical fact, no theory, according to the learned professor, can explain the mystery of solar influence, and its prodigious power over the development and produce of vegetables. Let us remark, before we leave this subject, that by a providential circumstance the present generations of mankind are profiting by the chemical force of the sun which nature has stored in her great vegetable _depôts_ for thousands of centuries. For instance, what is coal, which feeds all our industries, supplies our steam machines, ships, engines, and locomotives? It is the residue of those gigantic forests which covered the earth during the geological periods. The substance of the trees of the forests of the ancient world was at first changed into peat, which, becoming more and more compact by the action of ages, was finally pressed into the hard and heavy body which we call coal. But what was the cause, what was the first agent, which produced the trees of those forests, in the antediluvian times? It was the chemical force of the sun. This force, or, if the term be preferred, the products of the chemical force of the sun, have been accumulated and preserved in the wood, and then in the coal which that wood has become. We find it thus, and we use it, to our present profit. Thus, the glowing sunshine which lighted and warmed the ancient world, is not lost to us. Contemporary generations inherit those very rays, and that same chemical force. The power of the sun, which has slumbered in the coal for millions of years, arouses itself for us, comes forth into the day, and transforms itself in our hands into a mechanical agent. The light and heat of the sun, which play so great a part in the vegetable kingdom, exercise influence of a similar kind over the animal kingdom. If we reflect that plants are indispensable to the food of the majority of animals, that the creation of vegetables necessarily preceded that of terrestrial animals (since vegetables constitute their food), and that animals must inevitably disappear from the earth if plants ceased to exist; we shall be led to acknowledge that animals originate as certainly, though indirectly, from the force of the sun as the plants themselves.