PRACTICAL MECHANICS FOR BOYS TEXT

Defective. Not perfect; wrong in some particular. Diaphragm. A plate, such as used in a telephone system, to receive and transmit vibrations. Dissolving. To change from a solid to a liquid condition. Division plate. A perforated plate in a gear-cutting machine, to aid in dividing the teeth of a wheel. Dispelled. To drive away or scatter. Disinfectant. A material which will destroy harmful germs. Diametral pitch. The number of teeth in a gear as calculated on the pitch line. Dimension. Measurement; size. Ductility. That property of metal which permits it to be drawn out, or worked. Dividers. An instrument, like a compass, for stepping off measurements, or making circles. Diverge. Spreading out from a common point. Drift. A cutting tool for smoothing a hole in a piece of metal. Duplex. Two; double. Dynamite. An explosive composed of an absorbent, like earth, combined with nitro-glycerine. Dynamometer. An instrument for measuring power developed. Eccentric. Out of center. Echoes. The reflection of sound. Effervesce. The action due to the unity of two opposite chemicals. Efficiency. The term applied to the quality of effectiveness. Ellipse. A form which is oblong, or having a shape, more or less, like the longitudinal section of an egg. Electrolytic. The action of a current of water passing through a liquid, and decomposing it, and carrying elements from one electrode to the other. Elasticity. The quality in certain substances to be drawn out of their normal shape, and by virtue of which they will resume their original form when released. Embedded. To be placed within a body or substance. Emerge. To come out of. Emphasize. To lay particular stress upon. Emery. A hard substance, usually some of the finely divided precious stones, and used for polishing and grinding purposes. Enormous. A large amount; great in size. Enunciated. Proclaimed; given out. Equalization. To put on an even basis; to make the same comparatively. Eradicator. To take out; to cause to disappear. Escapement. A piece of mechanism devised for the purpose of giving a uniform rate of speed to the movement of wheels. Essential. The important feature; the principal thing. Expansion. To enlarge; growing greater. Equidistant. The same distance from a certain point. Evolved. Brought out of; the result of certain considerations. Facet. A face. Facilitated. Made easy. Flux. Any substance which will aid in uniting material under heat. The act of uniting. Fluid. Any substance in which the particles freely interchange positions. Flour emery. Emery which is finely ground. Flexible. The quality of any material which will permit bending. Float cut. The term when applied to a tool where the cut is an easy one. Flexure. The springing yield in a substance. Foot pound. A unit, usually determined by the number of pounds raised one foot in one second of time. 550 pounds raised one foot in one second of time, means so many foot pounds. Formulate. To arrange; to put in order from a certain consideration of things. Focus. The center of a circle. Foci. One of the points of an ellipse. Formation. The structure of a machine or of a compound. Fractured. Broken. Fundamental. Basis; the first form; the original structure. Fulcrum. The resting place for a lever. Fusion. Melting. The change of a metal from a solid to a liquid state by heat. Fusible. That which is capable of being melted. Fulminate. A substance that will ignite or explode by heat or friction. Gamut. The scale of sound or light, or vibrations of any kind. Gear. A toothed wheel of any kind. Gelatine. A tasteless transparent substance obtained from animal tissues. Globular. Having the form of a globe or ball. Glazed. Having a glossary appearance. Graphite. A metallic, iron-black variety of carbon. Graduated. To arrange in steps; a regular order or series. Grinder. Any mechanism which abrades or wears down a substance. Gullet. The curved notches or grooves between projecting parts of mechanism. Harmonizing. To make the various parts act together in unison. H. P. The symbol for horse power. Helico. A form resembling that of the threads of a screw. Hexagon. Six-sided. Heliograph. The system of signaling by using flashlights. Horizontal. Things level with the surface of the earth; like the surface of water. Hydrogen. The lightest of all the elements. A tasteless, colorless substance. Import. To bear, or convey as a meaning. Impulse. The application of an impelling force. Impact. A collision; striking against. Invariably. Constant; without failing. Inertia. The quality of all materials to remain at rest, or to continue in motion, unless acted on by some external force. Intersect. To divide at a certain point. The crossing point of one line over another. Interval. A space; a distance between. Intensity. Strained or exerted to a high degree. Interstices. The spaces between the molecules or atoms in a substance. Intermediate. Between. Intermeshing. The locking together of gear wheels. Internal. That which is within. Inability. Unable to perform or do. Initial. The first; at the start. Increment. One of the parts which go to make up the whole. Inference. Drawing a conclusion from a certain state of things. Insoluble. A substance which cannot be liquefied by a liquid. Indentations. Recesses, or cut-out parts or places. Induction. The movement of electricity through the air from one conductor to another. Inflammable. That which will burn. Inclining. At an angle; sloping. Inconsequential. Not of much importance. Isometric. That view of a figure which will give the relation of all the parts in their proper proportions. Jaw. The grasping part of a vise, or other tool. Joule. The practical unit of electrical energy. Key-way. A groove in a shaft and in the hub of a wheel, to receive therein a locking key. Kilowatt. A unit of electrical power; one thousand watts. Kinetic. Consisting of motion. Lacing. The attaching of the ends of a belt to each other. Lap. A tool, usually of copper or lead, on which flour emery is spread, with oil, and used to grind out the interior of cylinders. Lapping. The act of using a lap to grind out cylinders. Lacquer. A varnish for either wood or metal. Lazy-tongs. A form of tool, by means of which a long range of movement is attainable, and great grasp of power. Levigated. Reduced to a fine powder. Litharge. A form of lead used in paints for drying purposes. Longitudinal. Lengthwise. Luminous. That which has the capacity to light up. Magnet. A bar of iron or steel that has electricity in it capable of attracting certain metals. Manipulation. Capable of being handled. Mandrel. The revolving part of a lathe; a rod or bar which turns and carries mechanical elements thereon. Manually. Operated by hand. Margin. An edge. Malleability. Softness. The state of being formed by hammering. Magnetism. A quality of certain metals to receive and hold a charge of electricity. Major axis. The measurement across the longest part of an ellipse. Minor axis. The distance across the narrowest part of an ellipse. Meridian. The time when the sun crosses the middle of the heavens; midday. Metric. Measure; a system which takes the unit of its measurement from the circumference of the earth. Micrometer. A tool for measuring small spaces or intervals. Milling machine. A large tool for the purpose of cutting gears and grooves or surfaces. Miter. A meeting surface between two right-angled pieces. Momentum. That quality of matter which is the combined energy of mass and speed. Molecular. Any substance that is made up of any particles; the component elements in any substance. Modifications. Changes; improved arrangements. Multiplicity. Many; numerous; a large quantity. Mutilated. As applied to a gear, one in which certain teeth are removed. Nautical. Marine; applied to shipping, and the like. Neutralizes. Any substance, like a chemical, which, when added to another chemical, will change them both. Nitro-glycerine. An explosive made from glycerine and nitrogen. Oblique. At an angle; inclined. Obliterate. To wipe out. Obvious. That which can be seen; easily observed. Obtuse. A blunt angle; not noticeable. Odophone. An instrument for determining and testing odors. Olfactory. The nerves of the sense of smell. Orifice. An opening; a hole. Oscillation. A movement to and fro, like a pendulum. Oxygen. The most universal gas, colorless and tasteless; is called the acid-maker of the universe and unites with all known substances, producing an acid, an alkali, or a neutral compound. Oxidizing. To impart to any substance the elements of oxygen. Oxide. Any substance which has oxygen added to it. Pallet. A part of a tooth or finger which acts on the teeth of a wheel. Parallel. Lines or sides at equal distance from each other from end to end. Paraffine. A light-colored substance, produced from refined petroleum. Perimeter. The outer margin of a wheel; the bounding line of any figure of two dimensions. Periphery. The outer side of a wheel. Peen. The nailing end of a hammer. Persistence. That quality of all matter to continue on in its present condition. Perpendicular. A line drawn at right angles to another. Perpetual. Without end. Perspective. A view of an object which takes in all parts at one side. Physically. Pertaining to the body. Phonautograph. An apparatus for recording sound. Phonograph. An apparatus for taking and sending forth sound vibration. Phenomena. Any occurrence in nature out of the ordinary. Pitman. The rod or bar which connects the piston and crank. Pivot. A point or bar on which anything turns. Pinion. A small toothed wheel. Pitch. The number of vibrations. The term used to give the number of teeth in a wheel. Pitch diameter. The point from which the measurements are made in determining the pitch. Pivoted. A bar, lever, or other mechanical element, arranged to turn on or about a point. Plastic. A substance in such a state that it may be kneaded or worked. Planer. A large tool designed to cut or face off wood or metal. Porosity. The quality in all substances to have interstices, or points of separation, between the molecules. Potential. The power. Properties. The qualities possessed by all elements. Projecting. The throwing forward. The sending out. Promulgated. Put forth; enunciated. Protractor. A mechanic's and draughtsman's tool by means of which angles may be formed. Promote. To carry forward in a systematic way. Precision. Work done with care; observing correct measurements. Prony brake. A machine for determining horse power. Punch. A small tool to be struck by a hammer in order to make an impression or indentation. Quadrant. One-fourth of a circle. Quadrant plate. A plate on which are placed lines and numbers indicating degrees. Quadruplex. A term to designate that system of telegraphy in which four messages are sent over a single wire at the same time. Ratchet. A wheel having teeth at certain intervals to catch the end of a pawl or finger. Ratchet brace. A tool to hold a drill, having a reversible ratchet wheel. Rasp cut. A cut of a file which is rough, not smooth. Rake. The angle or inclination of the upper surface of the cutting tool of a lathe. Reverse. To turn about; in the opposite direction. Reciprocating. To go back and forth. Revolve. To move in an orbit or circle, as a merry-go-round. Reciprocity. To give back in like measure. Reflection. The throwing back from a surface. Resonance. The quality of vibration which adds to the original movement, and aids in perpetuating the sound. Refraction. The quality of light which causes it to bend in passing through different substances. Reducing. Bringing it down to a smaller compass. Rectilinear. A straight line. Retort. A furnace of refractory material to take high heat. Reamer. A tool designed to enlarge or to smooth out holes. Regulation. To do things in an orderly way; a system which sets forth certain requirements. Refractory. Difficult to work, and not easily fused. Recess. A hole, or a depression. Rocking. A lever which rotates only part way and then moves in the opposite direction. Rotate. A spindle which turns round. Compare revolve. Rosin. Certain gums; particularly the sap of pine trees. Roughing. The taking off of the first coating with a tool. Saturated. A soluble substance which cannot be further dissolved by a liquid. Scribe. To mark with a tool. Screw plate. A tool which has within it means for adjusting different cutting tools. Section lining. The marks made diagonally across drawings to indicate that the part is cut away. Shaper. A large tool for surfacing off material, cutting grooves, and the like. Shrinkage. The term applied to metals when cast, as all will be smaller when cold than when cast in the mold. Slide rest. The part of the lathe which holds the tool post. Sonorous. Having the quality of vibration. Slotted. Grooved, or channeled. Solvent. That which can be changed from a solid by liquids. Spelter. A combination of zinc and copper. A hard solder. Soldering. Uniting of two substances by a third, with heat. Spindle. A small shaft. Spur. The larger of two intermeshing gears. Socket. A depression or hole. Sprocket. Teeth in a wheel to receive a chain. Spiral. A form wound like the threads of a screw. Surface plate. A true surface made of metal, used as a means of determining evenness of the article made. Sulphate. Any substance which is modified by sulphuric acid. Substitute. An element or substance used for another. Superposed. One placed above the other. Swage. Tool for the purpose of changing the form in a material. Swivel. A point on which another turns. Surfacing. Taking off the outer coating or covering. Tap. A small drill. Tapering. An object with the sides out of parallel. Tangential. A line from the periphery of a circle which projects out at an angle. Tension. The exertion of a force. Tenacity. The property of a material to hang together. Tempering. Putting metal in such condition that it will be not only hard but tough as well. Technical. Pertaining to the strict forms and terms of an art. Texture. That of which the element or substance is composed. Threads. The ridges, spiral in form, which run around a bolt. Theoretically. The speculative form or belief in a subject. Tinned. The term applied to the coating on a soldering iron with a fluxed metal. Tines. Small blades. Torsion. The force exerted around an object, like the action of a crank on a shaft. Tommy. A lever to be inserted in a hole in a screw head for turning a screw. Transmitting. Sending forth; to forward. Trammel. A tool for the purpose of drawing ellipses. Traction. Drawing; pulling power. Tripping. A motion applied to a finger, which holds a pivoted arm, whereby the latter may be swung from its locked position. Triangular. Having three sides and three angles. Transverse. Across; at right angles to the long direction. Undercut. A wall of a groove or recess which is sloping. Undulatory. A wave-like motion, applied generally to light and electricity. Unit. A base for calculating from. Unison. Acting together; as one. Unsized. Generally applied to the natural condition of paper or fabric which has no glue or other fixing substance on it. Vaporising. To change from a liquid or solid to a gas. Variation. Changing into different conditions; unlike forms. Verge. The edge; usually applied to the shoulder of a watch spindle, particularly to the escapement. Vertical. Up and down. The direction of a plumb line. Velocity. The speed of an article through space. Vitascope. An instrument for determining the rate of vibration of different substances. Vibration. The movement to and fro of all elements, and by means of which we are made sensitive of the different forces. Vocation. The business or the calling of a person. Warding. The act of cutting a projection or guard, such as is usually found on the insides of locks, and the correspondent detent in the key. Watt. In electricity the unit of the rate of working in a circuit. It is the electro-motive force of one volt and the current intensity of one ampere. INDEX (Figures indicate the pages) A Acetone, 165. Acid, 119, 120, 156, 168. Acid, Acetic, 165. Acid, Carbolic, 166. Acid, Hydrofluoric, 170. Acid, Muriatic, 119. Acid, Nitric, 168, 169, 171, 173. Acid, Oxalic, 172. Acid, Pyrogallic, 172. Acid, Sulphuric, 169. Acoustics, 87, 157.