Page:Popular Science Monthly Volume 5.djvu/413

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PRIESTLEY'S DISCOVERY OF OXYGEN GAS.
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place, not through present and incessant interventions, but in obedience to ancient law? I recall what we all witness as respects the social condition of man, that, according as he advances in intellect, he lives under self-imposed rules, and that his reverence for law is the measure of his civilization; that it is the pride of that civilization to put in the place of an autocrat, dispensing instant rewards and punishments with his own hands, the ideal majesty of the law, which deals out inflexible justice to the good and evil, and makes no distinction of persons; and, reasoning in this manner, from insignificant beings and small things to those which are great, I conclude that a Pure Intelligence will rarely act by intervention, but always through law.

Through that astronomical agency to which I have referred—the action of light exerted during the period of the deposit of the coal—a purification of the atmosphere was effected to such an extent as gradually to enable warm-blooded animals to exist, the temperature to which they attain being directly dependent on the amount of oxygen they take from the air. All animals, from the first period of their coming into existence to the moment of death, are continually, by their respiratory effort, obtaining this gas, so essential to their very existence, and as continually expelling the effete and dead matters of their systems, under the forms of other airs—carbonic acid, ammonia, and the vapor of water. And thus the atmosphere is the source from which our bodies come, and to which they return, continually during life, and, with the exception of their earthy ingredients, totally after death, and the gases that are found in it are at once the agents and objects of the change. Had Priestley realized these things, could he have induced Chemistry by her witchcraft to compel the gas he had discovered to tell its own story, and how it determined his destiny, his imaginative but theological mind would perhaps have recalled the similarity of its own adventurous inquiry with that of the old Jewish king who visited the sorceress at Endor. Awakened by the power of her spell, there arose, from the enchanted circle over which she waved her wand, the form of an old man whose face was shrouded in his mantle. And he said, "Why hast thou disquieted me, to bring me up? To-morrow shalt thou and thy sons be with me."

Some seek for pleasure in the mere gratification of animal appetites, let us rather find it in the exercise of the intellect; and, when spring approaches, let us rejoice in the change, not so much because there is a promise of food, though we should never forget that all these vegetable products, of which so many are destined to delight our tastes, were mortal poisons while they were yet in the air, but chiefly because they are indications that all that is necessary for us as thinking beings is accomplishing. I have told you that the continuance of the life of man is indissolubly linked with the putting forth of the buds of trees. Let the one fail, and the other will speedily stop. Nay, more; as all our intellectual acts can only go on as a consequence of respiration, and