97. To-day we are to speak of optics, the science of seeing;—of that power, whatever it may be, which (by Plato’s definition), “through the eyes, manifests colour to us.”
Hold that definition always, and remember that ‘light’ means accurately the power that affects the eyes of animals with the sensation proper to them. The study of the effect of light on nitrate of silver is chemistry, not optics; and what is light to us may indeed shine on a stone; but is not light to the stone. The “fiat lux” of creation is, therefore, in the deep sense of it, “fiat anima.”
We cannot say that it is merely “fiat oculus,” for the effect of light on living organism, even when sightless, cannot be separated from its influence on sight. A plant consists essentially of two parts, root and leaf: the leaf by nature seeks light, the root by nature seeks darkness: it is not warmth or cold, but essentially light and shade, which are to them, as to us, the appointed conditions of existence.
98. And you are to remember still more distinctly that the words “fiat lux” mean indeed “fiat anima,” because even the power of the eye itself, as such, is in its animation. You do not see with the lens of the eye. You see through that, and by means of that, but you see with the soul of the eye.
99. A great physiologist said to me the other day—it was in the rashness of controversy, and ought not to be remembered, as a deliberate assertion, therefore I do not give his name, still he did say—that sight was “altogether mechanical.” The words simply meant, if they meant anything, that all his physiology had never taught him the difference between eyes and telescopes. Sight is an absolutely spiritual phenomenon; accurately, and only, to be so defined; and the “Let there be light,” is as much, when you understand it, the ordering of intelligence, as the ordering of vision. It is the appointment of change of what had been else only a mechanical effluence from things unseen to things unseeing,—from stars that did not shine to earth that could not perceive;—the change, I say, of that blind vibration into the glory of the sun and moon for human eyes; so rendering possible also the communication out of the unfathomable truth, of that portion of truth which is good for us, and animating to us, and is set to rule over the day and night of our joy and sorrow.
100. The sun was set thus ‘to rule the day.’ And of late you have learned that he was set to rule everything that we know of. You have been taught that, by the Sirens, as a piece of entirely new knowledge, much to be exulted over. We painters, indeed, have been for some time acquainted with the general look of the sun, and long before there were painters there were wise men,—Zoroastrian and other,—who had suspected that there was power in the sun; but the Sirens of yesterday have somewhat new, it seems, to tell you of his authority, ἐπι χθονὶ πουλυβοτείρῃ. I take a passage, almost at random, from a recent scientific work.
“Just as the phenomena of water-formed rocks all owe their existence directly or indirectly chiefly to the sun’s energy, so also do the phenomena interwoven with life. This has long been recognised by various eminent British and foreign physicists; and in 1854 Professor——, in his memoir on the method of palæontology, asserted that organisms were but manifestations of applied physics and applied chemistry. Professor ---- puts the generalisations of physicists in a few words: When speaking of the sun, it is remarked—‘He rears the whole vegetable world, and through it the animal; the lilies of the field are his workmanship, the verdure of the meadows, and the cattle upon a thousand hills. He forms the muscle, he urges the blood, he builds the brain. His fleetness is in the lion’s foot; he springs in the panther, he soars in the eagle, he slides in the snake. He builds the forest and hews it down, the power which raised the tree and that which wields the axe being one and the same.’”
All this is exceedingly true; and it is new in one respect, namely, in the ascertainment that the quantity of solar force necessary to produce motive power is measurable, and, in its sum, unalterable. For the rest, it was perfectly well known in Homer’s time, as now, that animals could not move till they were warm; and the fact that the warmth which enables them to do so is finally traceable to the sun, would have appeared to a Greek physiologist, no more interesting than, to a Greek poet, would have been the no less certain fact, that “Tout ce qui se peut dire de beau est dans les dictionnaires; il n’y a que les mots qui sont transposés”—Everything fine, that can be said, is in the dictionaries; it is only that the words are transposed.
Yes, indeed; but to the ποιητής the gist of the matter is in the transposition. The sun does, as the delighted physicist tells you, unquestionably “slide in the snake;” but how comes he to adopt that manner, we artists ask, of (literally) transposition?
101. The summer before last, as I was walking in the woods near the Giesbach, on the Lake of Brientz, and moving very quietly, I came suddenly on a small steel-gray serpent, lying in the middle of the path; and it was greatly surprised to see me. Serpents, however, always have complete command of their feelings, and it looked at me for a quarter of a minute without the slightest change of posture: then, with an almost imperceptible motion, it began to withdraw itself beneath a cluster of leaves. Without in the least hastening its action, it gradually concealed the whole of its body. I was about to raise one of the leaves, when I saw what I thought was the glance of another serpent, in the thicket at the path side; but it was the same one, which having once withdrawn itself from observation beneath the leaves, used its utmost agility to spring into the wood; and with so instantaneous a flash of motion, that I never saw it leave the covert, and only caught the gleam of light as it glided away into the copse.