308 THE EVIL OF DOGMA. planets traversing the circumferences of circles: they were mistaken. It is true this equality exists; only, not where they supposed. If they had sought it in the surfaces described by the vector radii, they would have anticipated Kepler's discovery of the laws which govern our world. But their astronomical dogmas prevented them from seeing the path which led to this great discovery. Hence we may conclude that Dogma is an evil thing. "I care not, Fortune, what you me deny ; Through which Aurora shows her bright'ning face; The woods and lawns by living streams at eve." F all the strata composing our planetary mass, the most important, so far as man is concerned, is, at the same time, the most superficial; for it is here that all the phenomena of life transpire. Our vegetable earth is the great laboratory in which are prepared all the solid, liquid, and gaseous aliments necessary for the nourishment of animal life. It is on the surface of the globe that men play their various parts. And why? Can it be for no other purpose than to modify, in some degree, its aspect, that they occupy the terrestrial surface? One would be tempted to think so on consulting what these majestic bimanes pompously designate their "Universal History." Regions for 310 THE LESSON OF MUTABILITY. - merly blooming with fertility,-gay with gardens, and orchards, and meadows, musical with brooks, and glorious with harvest, are now uncultivated and barren. Monuments which seemed adapted to defy the winds and the rains, and the corroding touch of the years, lie shattered in ruins; and with them the once populous cities and the once mighty empires of which they were the pride. The jackal howls among the broken columns of Tadmor; the sand-drifts have accumulated above the splendour of Memphis and Thebes. With their stones other monuments are raised, other cities are embellished, and other empires, which, in their turn, undergo the same unalterable fate: a perpetual relation of human forms, in every respect comparable with that which transpires in the bosom of the prolific earth, our common mother and nurse. But why do men wander so far from the straight way? Why do they their best to ensure each other's unhappiness? They seem, alas! ignorant of the tendency of their actions, while attaching themselves to things transitory, and despising things imperishable. These, indeed, they would utterly ignore; they would live, like the brutes, unconscious of their destiny, if, at the bottom of their indestructible conscience, there did not prevail a glimmer of light, though more or less eclipsed, if they did not all feel themselves attracted, if they did not all irresistibly gravitate, some more quickly, others more slowly, towards the sun of eternal truth and justice. Instead of moving with sidelong sinuous pace, instead of taking ninetynine steps backward for every one hundred taken in advance, they would all march onward in the way of progress; were it ON THE FREEDOM OF THOUGHT. 311 not that they pass their time in clipping their own wings; were it not that, to bend their heads the better- Veluti pecora ventri obedientia-they check the aspiring flight of that thought which would soar beyond the present; in a word, were it not that they lay a sacrilegious hand-unfortunate wretches!-on that which God Himself has respected in His creature-Liberty ! The doubt which perplexes us as to the great problem of our destiny, the doubt which allows so much latitude to the workings of our conscience,-does it not indicate the path we ought to follow? Should not men regard their freedom with peculiar reverence, when the Divinity they invoke has mercifully refrained from fettering it? Creatures of a day, who live as if you would never die! the contradictions and the miseries of which you so incessantly complain, are your own work. Help, help yourselves, by the development of your faculties, by the cultivation of your heart and mind, for herein you shall see the law and the prophets. Barren lip-service is nothing better than blasphemy! But let us return to the ground which we tread, and where our life-companions are the animals and the plants. The uppermost stratum of our globe undergoes the direct action of the light and heat of the all-vivifying "orb of day." This action, very unequal in its effects, and most important to understand, has scarcely been touched as yet by scientific research. Our geologists, having been more busily engaged with the inside than the outside of the earth, have broached 312 CHEMICAL ACTION OF LIGHT. certain plausible theories—for the most part of a very dubious character-respecting the central fire, Plutonism and Neptunism, the stratification of the planets, the formation of mountains, valleys, and basins. Our mineralogists, thinking far less of the chemical molecular constitution of the different formations than of their crystalline constitution, have minutely studied the physical qualities and geometrical forms of the integral parts of the rocks; but neither have condescended to direct their inquiries to the layer of soil trodden underneath their feet. Yet this very layer of arable earth, to which all bodies must return after death what they have taken from it during life, this much despised humus, furnishes all our agricultural products, the very foundation and support of our material existence. - To touch industrial occupations-to meddle with trade, commerce, or agriculture-is unworthy of Science! Such is the silly cry of the many distinguished savants who pride themselves on what they call their "freedom from selfish considerations." Be it so; but then you ought surely to be consistent, and never regard science as a profession or a bread-winner. ON THE CHEMICAL ACTION OF LIGHT. It is no easy study to investigate the modifications and chemical effects which the terrestrial surface is capable of receiving or undergoing, either from the direct rays of the sun, or from diffused light. It requires new methods of inquiry, -methods frequently of extreme delicacy, as the labours of |