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Knight's Mechanical Encyclopedia (ed. Knight) 42 0 Browse Search
Historic leaves, volume 1, April, 1902 - January, 1903 2 0 Browse Search
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Browsing named entities in Knight's Mechanical Encyclopedia (ed. Knight). You can also browse the collection for Ramsden or search for Ramsden in all documents.

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Knight's Mechanical Encyclopedia (ed. Knight), C. (search)
2. An unburned brick. Cob′le. （Nautical.) A small fishing-boat, of great antiquity in the British Islands. Coggle. Cob′ler. A bent rasp for straightening the shaft of a ramrod. Co′bourg-cloth. （Fabric.) A lady's dress goods, cotton-chain, woolen-filling, twilled on one side. It may be considered an imitation of merino. Cob-wall. A will built up solid of a compost of puddled clay and straw, or of straw, lime, and earth. Cob′web-mi-crom′e-ter. Invented by Ramsden (1735 – 1800). A micrometer in which cobwebs are substituted for wires. By turning the screw which approximates or separates the frames across which the cobweb-threads are stretched, the slightest alterations of the lines can be estimated, and a difference, even of 1/100000 of an inch be rendered appreciable. Coch′le-a. 1. An ancient term for an engine of spiral form. The screw whereby Archimedes launched the great galley of Hiero is also called cochlea by Athenaeus. A s
Knight's Mechanical Encyclopedia (ed. Knight), D. (search)
rom′e-ter. A form of the double image micrometer, introduced by Ramsden (1735-1800), in which the divided lens is in the eye-tube. In thene for dividing circles, which also served to cut clock-wheels. Ramsden, in 1766, contrived his dividing-engine, and in 1777 received a reward of pound 615 from the Board of Longitude. Following Ramsden were the Troughtons, father and son, the latter of whom received the CopleyRoyal Society of England for his improved method of graduation. Ramsden's circular dividing-engine consisted of a large wheel moved by a tto 240 parts, each of which was designed to contain nine teeth. Ramsden's screw-cutting apparatus. The first application of the tangens Traite d'horlogerie, etc., Paris, 1741. Fig. 1677 illustrates Ramsden's application of the principle of the engine just described in oriither projected on motherof-pearl or measured by optical means. Ramsden proposed for this purpose the doubleimage micrometer, an instrumen
Knight's Mechanical Encyclopedia (ed. Knight), G. (search)
, the are of 60° was divided into 64 parts, making 96° instead of 90° to the quadrant. It was deemed preferable to make the proportionate correction on each angle, rather than to trust to the uncertainty of a division to thirds or fifths. Bird, 1750, subsequently improved the system by constructing scales of equal parts, enabling him to preserve the division of 90° by successive bisections. His manual skill and care procured him merited reputation as a maker of accurate instruments. Ramsden followed with his dividing-engine, 1766, the general principles of which, variously modified and improved by Troughton and others, are still employed in the construction of like instruments. In this, a horizontal wheel, turning on a vertical axis, has a toothed edge, which is advanced a certain amount, say 10′ of are by each revolution of an endless screw with which it gears. The screw is turned by a treadle, the connecting mechanism being such that it may be adjusted to turn a whole re<
Knight's Mechanical Encyclopedia (ed. Knight), M. (search)
e cause, whether arising from a change in its own weight or its temperature, or both. Boyle's statical manometer. Ramsden's manometer, used in the Arctic researches, had a tube of small bore with a ball at the end; the barometer being sp. grad the instrument will show the differences in the density of the air arising from the changes in its weight and heat. Ramsden found that a heat equal to that of boiling water increased the bulk of the air from what it was at the freezing-point by invented the circular micrometer, which was used by Lecaille in 1742, and Olbers, 1798, and improved by Frauenhofer. Ramsden, about 1780, suggested the use of cobwebs as a fine filament substitute for wire. It has been credited to Troughton. ong celebrated instruments may be mentioned the mural circle made by Graham, for Halley, at Greenwich, and those made by Ramsden in 1788, for Piazzi, at Palermo, and one for Dublin. See graduating-instruments. The mural circle is so called beca
Knight's Mechanical Encyclopedia (ed. Knight), O. (search)
scope. Camera-photograph.Doublet. Camera-solar.Draw-tube. Dynactinometer.Optigraph. Dynameter.Optometer. Engiscope.Oxy-hydrogen microscope. Erecting eye-piece.Parabolic illuminator. Erecting-prism.Parabolic reflector. Erector.Perspective-glass. Eye-glass.Polariscope. Eye-rim.Polarizer. Field-glass.Polarizing-apparatus. Finder.Polemoscope. Fishing-tube.Positive eye-piece. Florascope.Prism. Folder.Pseudoscope. Frog-plate.Quadrant. Goggles.Rice-glass. Graphic microscope.Ramsden's eye-piece. Growing-slide.Reading-glass. Hand-magnifierReflecting-circle. Heliometer.Reflector. Helioscope.Refracting-circle. Heliostat.Repeating-circle. Heliotrope.'Scope. Horizon. ArtificialScotoscope. Horizon-glass.Sector. Illuminator.Sextant. Index-glass.Side-reflector. Indicator.Slide. Iris-diaphragm.Solar camera. Jointed microscope.Solar eye-piece. Kinescope.Solar microscope. Lens.Spectroscope. Level.Specticle-gage. Lieberkuhns.Spectacles. Linen-prover.Speculum. L
Knight's Mechanical Encyclopedia (ed. Knight), Q. (search)
image of an object reflected from a mirror fixed on a pivoted arm is reflected to the other mirror on a fixed arm, where it is again reflected, and by moving the pivoted arm the image is brought into apparent coincidence with the sea horizon, which is viewed through a part of the fixed mirror left unsilvered for that purpose. The movable limb is provided with a vernier, which indicates the degrees and minutes of elevation on the graduated fixed limb. Gunner's quadrant. Graham, Bird, Ramsden, and Troughton are the great names in the history of this instrument, their celebrity being especially due to their great successive improvements in graduating Instru-ment (which see). 2. An instrument used by gunners for giving a cannon or mortar the angle of elevation necessary to attain the desired range. It has a graduated arc and a plumb-line, which indicates the angle of elevation upon the arc when one arm is placed within the bore or the other against the face of the piece in a p
Knight's Mechanical Encyclopedia (ed. Knight), R. (search)
d ends of the rubbers are pressed against the ramrods by springs, and the rubbers receive a rapid motion while the ramrods are slowly revolved. Rams′den's eye-piece. The positive eye-piece, principally used in micrometers, and invented by Ramsden, a celebrated instrument-maker in England (1735-1800). His name is associated with science as the maker of the celebrated dividing-engine, and he is known by a number of his instruments, of great accuracy, in several European observatories, — sextants, telescopes, and mural circles. The Ramsden eye-piece has two plano-convex glasses, each of which presents its concave side to the object-glass. See positive eye-piece. Ran. 1. (Rope-making.) A reel of 20 yarns. 2. (Nautical.) Yarns coiled on a spun-yarn winch. Rand. （Shoemaking.) One of the slips beneath the heel of a sole, to bring the rounding-surface to a level ready to receive the lifts of the heel. Ran-dan′. （Nautical.) A mode of rowing with
Knight's Mechanical Encyclopedia (ed. Knight), S. (search)
subsequently removing the metal between the threads. Directions are also given for setting off and forming the teeth of the corresponding worm-wheel. One of the earliest attempts to obtain extreme accuracy in originating screw-threads was by Ramsden, in his dividingen-gine, 1766. See dividing-engine. Great attention was subsequently devoted to the subject by Maudslay, who, on entering upon his distinguished career as a mechanician, found the screws, which perform so many important func, it was again measured with glass tubes 20 feet in length, furnished with a peculiar apparatus for making the contacts. In the subsequent measurement of the same line for the Ordnance Survey, two steel chains of 100 feet in length, and made by Ramsden, were employed. One of these was kept as a measuring-chain; the other was kept for the purpose of comparing the measuring-chain with it before and after the operation. In the act of measuring, the chain was laid in a trough supported on trestl
Knight's Mechanical Encyclopedia (ed. Knight), T. (search)
as also a horizontal. See under telescope for notice of the first use of telescopes in triangulation or measuring angles. The first survey made by an instrument with a perfect circle is said to be that of Zealand, by Bugge, in 1762-68. Ramsden's theodolite had a circle 3 feet in diameter, and was completed in 1787. It had two telescopes of 36 inches focal length. It was used for a triangulation to connect the observatories of Greenwich and Paris, and also in the English, Irish, and of watches and chronometers, a diamond-drill such as is shown in Fig. 6804 is used: a represents the flat surface and b the edge of such a tool. It may also be used for engraving extremely fine lines. The diamond was first used for turning by Ramsden in cutting the hardened steel screw for his dividing-engine. Diamond-turning tools. See under the following heads: — Astragal tool.Gouge. Bead-tool.Hanging-tool. Bevel-tool.Heel-tool. Bottom-tool.Hook-tool. Broad-tool.Inside tool.