Light ray

“ And the reason is that a ray of sunlight is really a bundle of lesser rays, each of which has its own colour. If a ray of light is made to pass through a prism, these lesser sub-rays are spread out upon wall or floor, always in the same order, from violet at one end to red at the other end. Light is believed to be due to enormous numbers of most minute wavelets; and for each colour the wavelets have a definite but different size. ”

“ It is hardly necessary to occupy time with experiments in showing that a ray of light can be reflected and refracted by mirrors and prisms, and converged or diverged by transparent lenses. These are simple optical facts, and if you are not familiar with them it will be easy for you to make their acquaintance by studying any simple book upon optics; but I should like to draw your attention to the fact that, in addition to rays of light and electric radiation, we are acquainted with another kind of radiation, which is also susceptible of being refracted, and that is commonly called dark heat. ”

“ In moving about to get different points of view, he suddenly found that he had come between it and the ray, and that the crystal none the less remained luminous. Greatly astonished, he lifted it out of the light ray and carried it to the darkest part of the shop. ”

“ Thus if the ray of sunlight entered through the window of one room and passed out through another on the other side, traversing the room, and if it met nothing on the way, or if there were no specks in the air for it to strike, the room would have no more light than before, neither would the ray of light be visible. ”

“ We may, however, sketch out a brief chapter in modern sidereal astronomy, which seems to throw a ray of light into the constituents of the vast abyss of space which lies beyond the range of our telescopes. The ray of light is no doubt but a feeble one, but we must take whatever information we can obtain, even though it may fall far short of that which an intellectual curiosity will desire. ”

“ When a ray of light enters obliquely into the atmosphere, instead of passing directly through, it bends a little downwards, so that the greater portion of the rays which thus enter the atmospheric mass, descend by inflection to the earth. We then enjoy the benefit of that light which would otherwise have been totally lost. We perceive the light of day an hour before the solar orb makes its appearance, and a portion of its light is still retained 59 when it has descended nearly eighteen degrees below our horizon. ”

“ A ray of light passing through an aperture into a dark room, proceeds in a straight line; a fact of which any one may be convinced by going into a darkened room and admitting light only through a small aperture.
Light also moves with great velocity, but becomes fainter as it recedes from the source from which it eminates; in other words, diverging rays of light diminish in intensity as the square of the distance increases. For instance let a fig. ”

“ Ordinary light—according to the undulatory theory—is due to vibrations transverse to the direction of the ray, but varying so rapidly as to show no particular direction of their own, the fronts of the light-waves crisscrossing at all angles. ”

“ Emily. But do not the rays which are projected in different directions, and cross each other, interfere, and impede each other's course?
Mrs. B. Not at all. The particles of light, are so extremely minute, that they are never known to interfere with each other. A ray of light, is a single line of light, projected from a luminous body; and a pencil of rays, is a collection of rays, proceeding from any one point of a luminous body, as fig. 2.
Caroline. Is light then a substance composed of particles, like other bodies? ”

“ Accepting the theory of vibrations, and applying it to the elucidation of the phenomena of light—it is unnecessary, we think, to believe that a ray of white light contains rays in a state of colour. It is said that if we divide a circular surface into parts, and paint the various colours in the order and proportions in which they occur in the refracted ray, and then spin the circle with great velocity, the colours will blend and appear white. ”

“ And if the ray were completely pure and free from all these atoms and particles, even from the minutest specks of dust, it would appear completely dark and invisible to the eye, since everything that could be seen would be absent from it — namely, the objects of sight. For the eye would find no objects whereon to rest, since light is no proper object of vision, but the means whereby that which is visible is seen ”

“ Where the transverse impulse, which is due to the varying degree of TrÃ1⁄4bung in the light-realm, is directed towards the latter's edge, the intermingling of the Dark-ingredient and the Light-ingredient, contained in that realm, is such that Dark follows Light along its already existing gradient, thereby diminishing steadily. Hence our visual ray, meeting conditions quite similar to those occurring when we look across the light-filled atmosphere into universal space, notifies us of the presence of the blue-violet colour-pole. ”

“ Sometimes one, and sometimes a quick succession of luminous currents run from one end of the arc or bow to the other, so that the rays rapidly increase in brightness; but it is impossible to say whether the coruscations themselves are actually affected by a horizontal motion of translation, or whether the more vivid light is conveyed from ray to ray. The rays occasionally dart far past the zenith, vanish, suddenly reappear, and, being joined by others from the arc, form a magnificent corona or immense dome of light. ”

“ A ray of light, when transmitted obliquely from one transparent body to another of different density, undergoes, at the point where it strikes the common surface of the two planes, a sudden change of direction. ”

“ This general law being interfered with by the expansion of the lower layers, refraction of the light rays,—or the deviation which they suffer in passing from one medium into another of differing density—takes place in a manner contrary to that when the atmospheric layers are normally superposed, and the mirage [1] is produced, an optical illusion, which causes us to see objects, below the horizon or in the air, inverted. ”

“ A quivering beam of yellow light; then Elza saw that upon occasion, as Tarrano's finger slid a lever, the beam narrowed, intensified to a bright lavender. And now where it struck, the vegetation withered. Blackened, sometimes burst into tiny flame, and parted thus before them as they advanced.
The jungle was silent; yet, as Elza listened, beneath the crackle of the burning twigs she could hear the tiny myriad voices of insect life. Startled voices as the heat of Tarrano's beam struck them. Rustling leaves; breaking twigs; things scurrying and sliding away, unseen in the darkness. ”

“ Accordingly, the experiment of producing interference between two sets of light rays so that they destroy each other is a strong argument in favour of the view that light must consist in some kind of wave-motion existing in a medium susceptible of supporting it, filling all space, and existing in all transparent bodies. ”

“ The audience was hushed and expectant. The white patch of light overhead spread until it encompassed all the top of the globe. The whole area was glowing. The people were white, spectral shapes, transparent! And the top of the globe was transparent; I saw the night sky, with the gleaming reddish stars.
It was, in a moment, as though we were staring up at a huge square window orifice cut in the top of the room. A broad vista of cloudless sky and stars was visible. Across it, like a shining sword, was a narrow, opalescent beam.
"The Earth-beam which I planted," Molo whispered triumphantly. ”

“ Light always travels in straight lines when in a medium of uniform density, such as water, air, glass, etc., but on passing from one medium to another, such as from air to water, or air to glass, the direction of the light rays is changed, or, to use the correct term, refracted. This refraction of the rays of light only takes place when the incident rays are passed obliquely ”

“ The Very Young Man, as he lay prone, looked upward, and saw the sunlike light above fall swiftly down across the sky and disappear below the horizon, plunging the world about them into the gloom of a semi-twilight. ”

“ I remember now that my first thought was surprise that I should be able to visualize things of strangeness. But now I know that once over the Borderland my mind itself had changed, yet retaining of its old self just enough, so that I might be conscious of the strangeness. In a grey half-light of luminosity seemingly inherent to everything, I found myself standing upon a hillside, gazing down an empty slope of greyness. Was it land? I can only say that it seemed solid beneath me; solid, quivering with a tiny tremble; vibrating, and within itself vaguely luminous. ”

“ And the light burst with an exploding puff. The black metal cubby walls seemed to melt like phantoms in a dream. A titan's blowtorch, the opalescent light shot upward, a circular ten-foot beam, eating its way through all the city levels as though they were paper, up through the city roof.
Molo's cubby was gone. His mechanism was eaten by the light and destroyed. There was only this motionless, upstanding beam, contacted here with the Earth, streaming like an opalescent sword into the starry sky. ”

“ The gray area was shrinking to a blob, a blob of gray shining in a brilliant light. Directly beneath us, stretching to the horizon on both sides, lay an undulating white level surface. The single blob of gray was down there on it. And off in the distance, where the surface seemed abruptly to end, gigantic blurs loomed into the blue sky.
Dr. Weatherby was calling me to the tower. I found him trembling with eagerness. “Leonard, I have the electro-telescope working. Look through it.”
I gazed first through the front and overhead tower windows. The white disk filled a perceptible area of the sky. ”

“ The stars paled around it. A flood of yellow light lay upon the sea in a broad path of rippling gold.
The island was bathed in the golden flood. We were much closer to it now, swooping a few hundred feet above its beach which along here was broad and hard. The jungle was beside us, a fairyland of tropical verdure.
Warmed by the waters of the sea, and perhaps by hidden fires of the cone-shaped hill, the vegetation grew to giant size.
A giant forest edged with gold, mysteriously dark, romantic, amorous, scented with spices and the heavy perfume of flowers. ”

“ Beneath me was a limitless tract of grey slime which rose and fell torpidly as with the breathing of a somnolent subterranean thing. The moonlight burned brightly on it, and crawling across it from some remote place came—trees?—snaky-rooted things whose prehensile branches bore, instead of leaves, flexible lenses.... They left behind them red trails on the slime, and excrementory ribbons of thin blue vapor streamed from their topmost appendages. Occasionally they paused to feed, focussing their lenses upon the gelatinous ground, which became luminously white under the concentrated light. ”

“ All light carries an image of something—that’s why we can see things.
“Now when light leaves the earth and goes out into space it takes with it an image of the earth and everything that is happening on the earth.”
“Right,” said Tubby. “Go on.”
“Now some of this light may have to travel a hundred years before it reaches a star. When it does it mixes with other light and is reflected back in another hundred years to us. But—mark you this—but it still carries the image of the earth and what happened on the earth when it was here.” ”

“ Way back in the days when he was mule-boy Jimmy could remember sitting alone in the great dark silences of the mine, listening to its vague, distant, muffled sounds, and thinking of the great world outside—the world of light and air and color, the world he knew so little about, was in so seldom, and dreamed of so constantly.
Jimmy Rand was by nature a dreamer. He had imagination, which, to one who mines coal, is neither necessary nor desirable. ”

“ The Earth hung over us, flattened beyond the full. The stars blazed to mingle with the Earthlight and illumine these massive crags of the Archimedes walls. But no speck appeared to tell as that the ship was up there.
We were on the curving side of the Archimedes wall which fronted the Mare Imbrium to the North. The plains lay like a great frozen sea, congealed ripples shining in the light of the Earth, with dark patches to mark the hollows. Somewhere down there—six or eight thousand feet below us now, or even more than that, for all I could tell—Miko's encampment lay concealed. ”

“ So it now seemed to be from Elza to me. Georg, out of bed now beside me, urged me to greater efforts of concentration, that I might understand what message Elza was sending.
"Elza! Elza dear! Where are you? What is it?"
I murmured the words to myself as with all my power, I thought them over and over, flinging out the thoughts like radio waves into the night. Mysterious vibrations! In an instant, from here—everywhere in the universe. Who knows their character? Their speed? The speed of light a laggard perhaps beside the flash of a thought! ”

“ Tonight, all of us, Poe and Bierce and Hamlet's father, we burn together. They will make a big heap of us and burn us like a bonfire, like things of Guy Fawkes' day, gasoline, torch-light, cries and all! ”

“ Argo was leering. "Death? Yes! If you touch that violet light! Death, of course. But you won't touch it! You will stand and watch—stand silently for you know that if you shout, the vibrations will bring the beam upon you. You won't move—you'll stand and watch me kill your Princess Maida—not quickly—she is too beautiful for that. You, Georg Brende—you, Wolfgar, traitor from Mars. You shall see your Princess Maida die—this would-be traitoress to my Master Tarrano!" ”