Disk

“ I put in the key, swung open the door—and there before me was a section of a huge disk going round overwhelmingly, and all splashed and dripping as it revolved, with great jets of weedy-smelling water.
I say “disk,” for the arms to this side had been boarded in, that none, I supposed, might gather hint of what lay beyond.
The eyes into which the shaft ends of the wheel fitted were sunk in the floor level, flush with the lintel of the cupboard door that lay furthest from the window; so that only the left upper quarter of the slowly spinning monster was visible to me. ”

“ When a fairly acute eyed observer sets himself to scan the telescopic disk of the planet in steady air, he will, after noting the dazzling contour of the white polar cap and the sharp outlines of the blue-green seas, of a sudden be made aware of a vision as of a thread stretched somewhere from the blue-green across the orange areas of the disk. ”

“ Above the disks is a bar to which are pivoted a series of scrapers, one for each disk, which are held to their work with a yielding action, being thrown out of operation when desired by the levers shown in connexion with the operating bar. Pans on the main frame are used to carry weights to hold the disks down to their work. The cut away disk harrow differs from the ordinary disk harrow in that its disks are notched and so have greater penetrating power. ”

“ Face the outer side and cut a sharp V-center in it; then grind the periphery to the required diameter. Next fasten the finished disks onto the work in their correct locations with their peripheries in contact, and then set one of the disks exactly central with the lathe spindle by applying a test indicator to the center in the disk. After removing the disk and boring the hole, the work is located for boring the other holes in the same manner. [Pg 9]
Fig. 7. Hinge Jig Templet Illustrated in Fig. 6
Small disks may be secured to the work by means of jeweler’s wax. ”

“ If a disk with a narrow radial slit, about half a millimetre (1⁄50 inch) wide, is caused to rotate at the rate of about one turn per second in front of a bright background, such as a sheet of ground glass with a lamp behind it, the moving slit assumes the appearance of a fan-shaped luminous patch, the brightness of which diminishes with the distance from the leading edge. And if the eyes are steadily fixed upon the centre of the disk, it will be noticed that this bright image is streaked with a number of dark radial bands, suggestive of the ribs or sticks of a fan. ”

“ You can make the disks on some strings all of one size; on others they may graduate down to quite small ones at the ends. When the disks are cut out, lay one down, bottom side up, H (Fig. 209) . Cover this with paste, then lay a white cotton string across the disk, directly through the middle. Allow about six inches of the string to extend beyond the disk, and let each string be one yard long. Before the paste has time to dry, press the mate of the disk, G (Fig. 209) , on top of H, over the string, taking care to have the edges even. ”

“ When the disk will enlarge so as to make a ring of diluted white light round its circumference, as the sliding tube holding the eye-piece is pushed in or drawn out, the cell may be finally fixed by the screws passing through its elongated holes. ”

“ For instance, if we are to consider a certain red object which may be represented by the standard red disk, we place a medium sized disk of that color on the spindle, and in front of it, smaller disks of white and black united. By rotation the white and black disks become a neutral gray at the center of the red disk. If this gray is made nearly white all observers will agree that the gray is lighter than the red, and if it is nearly black the opinion will be equally unanimous that it is darker than the red. ”

“ Cut out a disk, or circular piece of cardboard just large enough to fit the tube, see Fig. 149, and push a pin point or needle through the center to make a small, clean hole. Next, glue this cardboard disk in the tube 1⁄2 an inch from one end. The disk must be glued in the tube so that no light can leak around the edge.
If, now, you look at the Sun through the pinhole telescope, as shown in Fig. 150, you will get a better view of it than if you look at it [Pg 139] through a pinhole in the cardboard alone, for the tube shuts out all the other rays of light from the eye. ”

“ They’re the gizmos into which you insert the floppy disks through slots in the computer.
From the outside a disk looks square. It’s inside a container that helps protect it from fingerprints and other threats to the plastic disk’s magnetic coating.
You can’t cover the delicate disk completely, though. Some of it must touch the head of a disk drive. A head “writes” magnetic patterns on the oxide coating of a disk; in other words, it stores information that you’ve typed into your computer or the results of your calculations. ”

“ C is an insulated disk over which is suspended another disk attached to the arm of a balance. A weight is put in the opposite scale pan and a measured charge of electricity is given to the disk C just sufficient to tip over the balance. Snow-Harris found that this charge varied as the square root of the weight in the opposite pan, thus showing that the attraction between the disks at given distance apart varies as the square of their difference of potential. ”

“ Now since the outside rim from 6,5 to 8,8, which reflected less than half the light of the mirror, produced a spurious disk less than ,18 in diameter, and the whole light as we have seen gave a disk of ,31, it is evidently not the quantity of the light, but the part of the mirror from which it is reflected, that we are to look upon as the cause of the magnitude of the spurious disks of objects. ”

“ I recognized it; and as I watched, its disk grew larger, looking like the Moon a few days before the full. After a while I could distinguish the principal geographical aspects in the growing disk,—the snowy patch at the North Pole, the outlines of Europe and Asia, the North Sea, the Atlantic, the Mediterranean. The more steadily I fixed my gaze, the better I could see. Details became more and more perceptible, as [59] if I were gradually changing the lenses of a microscope. ”

“ In Fig. 2 we have a disk of half-inch wood, twelve inches in diameter, with an opening in the center four inches across, to hold the condensing lens, a; b is a mirror five inches wide and ten inches long, turning on an axis which passes through the supports, c c, the latter being attached to the disk. ”

“ Close around the bright whiteness of the disk, and shining far more beautiful by contrast with that whiteness than as seen against the black disk of the moon in total eclipses, stood the colored region called the chromatosphere, not red, as it appears during eclipses, but gleaming with a mixed lustre of pink and green, through which, from time to time, passed the most startlingly brilliant coruscations of orange and golden yellow light. ”

“ A target or sighting disk was mounted on the stick. This disk was 6 inches in diameter, and was sawed out of a 6-inch square board by making
Fig. 81. The Sighting Disk straight cuts across the corners and then smoothing off the edge to a perfect circle with a draw-knife. The thickness of the disk was only 1/2 inch. At the back of the disk we fastened a block of wood with a slot cut in it to receive the rod, as shown in Fig. 81. To hold the disk at different heights 79 on the rod a small bolt was used. ”

“ In the disk plough, which is built both as a riding and a walking plough, the essential feature is the substitution of a concavoconvex disk, pivoted on the plough beam, for the mould-board and share of the ordinary plough. This disk is carried on an axle inclined to the line of draught, and also to a vertical plane. As the machine is drawn forward the disk revolves and cuts deeply into the ground, and by reason of its inclination crowds the earth outwards and thus turns a furrow. ”

“ A crown disk may, however, be melted a number of times without serious injury. In many cases—perhaps the majority—the artisan finds that after all his months of labor he cannot perfectly clear his glass of the noxious veins, and he has to break it up into smaller pieces. When he finally succeeds, the disk has the form of a thin grindstone two feet or upward in diameter, according to the size of the telescope to be made, and from two to three inches in thickness. The glass is then ready for the optician. ”

“ A small Family of Fishes of little value or importance either in a commercial or scientific point of view, is distinguished under the above name by a curious sort of sucking disk, by means of which they are enabled to adhere to the rocks of the bottom, or any other substance. This disk is situated on the inferior surface of the body, and is formed by the union of the large pectorals, which are connected by a membrane. In some of the genera the ventrals unite with the pectorals to make the disk; in others, they form a second circular disk in immediate contact with the other. ”

“ Motion is communicated to the disk by a train of wheels which is wound up with a winch and which is actuated by a weight of one hundred and fifty kilograms placed behind the chamber. The motion of the disk is arrested by a brake, and a bell maneuvered from the interior serves to give orders to an aid either to set the disk in operation or to stop it.
Fig. 7 shows the inner arrangement of the chamber, a portion of one of the sides being removed to show the photographic apparatus, A, placed upon a bracket before the screen. ”

“ As soon as the disk obtains a speed of ten turns a second, the regulator maintains this speed with perfect uniformity. The disk moves in front of the sensitized plate a few millimeters only; then, knowing [469] the angular value of each of the openings, the period of exposure is easily deduced therefrom.
FIG. 8.—WALKING MAN, CLOTHED IN WHITE,
PASSING ACROSS THE FIELD.
The condition most difficult of fulfillment is the absolute darkness of the screen before which the photographs are taken. ”

“ Stylodictya solmaris, n. sp.
All rings of the disk concentric, polygonal, with eight to sixteen rounded corners; their breadth increases from the centre; eighth ring twice as broad as the second. Pores subregular circular, large, only one pore on the breadth of each ring. Twenty to thirty marginal spines, bristle-shaped, undulating, about as long as (or longer than) the diameter of the disk.
Dimensions.—Diameter of the disk (with eight rings) 0.2; breadth of the inner rings 0.005, of the outer 0.012; pores 0.004 to 0.008.
Habitat.—South Atlantic, Station 332, depth 2200 fathoms. ”

“ As will be seen, an ordinary combination square is used in connection with a disk, the head of the square being set at different points on the blade according to the angle that is desired. Theoretically, a one-inch disk could be used for all angles from about 6 degrees up to a right angle, but in practice it is more convenient and accurate to employ larger disks for the larger angles. ”

“ On Plate 75 the chief figure is that of Kingsborough's supposed crucified Quetzalcoatl; on the body is a large sun or circular disk with seven points, but in the lower margin, where there is the proper space for another, the circle is pierced by the obsidian knife of the priest who holds the withdrawn heart in his hand. Around the figure are similar but smaller disks; counting these we find there are eight, the exact number of points required to complete the central disk, and the number of periods (Indications) in an age. ”

“ Another experiment will further illustrate this method of study. An apparatus is so contrived that a colored disk can be made darker or brighter by the operator, and a measure of the change be recorded. (See illustration on opposite page, rear group.) The persons operated on do not know what change is made, or whether any will be made or not. They first look at the disk for ten seconds, taking good note of its color. Next, the operator changes the shade (or not) as he sees fit. ”

“ In Plate 14, fig. 1, I have shewn the apparatus presented at the Exchange, as mentioned in page 110 preceding. A B is the stand; C D is a disk turning on the centre E; b a is the transparent line cut through the stand, and representing the place of contact of two wheels geering together. It is there seen, (supposing the disk to turn in the direction of the arrow) that the action of the teeth, is always progressive along the transparent line a b ”

“ Fig. 15 shows the very convenient arrangement of the eye-end of the instrument. The disk, 30 with its small projecting handle enables the 2 segments of the divided object to be moved rapidly or with any required delicacy relative to each other. The disk 32 operates the wire gauze screens for equalizing the brightness of the two stars under observation. The dial between 30 and 32 indicates the screen in use. 18 clamps and 19 gives slow motion in declination; 20 clamps and 21 gives slow motion in right ascension. ”

“ Since a slide is possible, it follows that a disk is also possible. This particular cipher disk, on which one alphabet runs forward and the other backward, was used long ago in our own army, and is widely known in this country as “The United States Army Cipher Disk.” Most persons, apparently, prefer the slides, on which the letters are always right-side up, and the preparation of which does not involve the division of a circle into 26 equal arcs. ”

“ Light has given us one or two other scientific prophecies. Poisson, from theory, pronounced that, in the case of an opaque circular disk, the illumination of the centre of the shadow caused by diffraction at the edge of the disk would be precisely the same if the disk were altogether absent. ”

“ Practically all calculating machines contain a “counting work,” a series of “figure disks” consisting in the original form of horizontal circular disks (fig. 1) , on which the figures 0, 1, 2, to 9 are marked. Each disk can turn about its vertical axis, and is covered by a fixed plate with a hole or “window” in it through which one figure can be seen. On turning the disk through one-tenth of a revolution this figure will be changed into the next higher or lower. Such turning may be called a “step,” positive Addition machines. if the next higher and negative if the next lower figure appears. ”