Telegraphy: A Detailed Exposition of the Telegraph System of the British Post Office |
Contents
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Common terms and phrases
acid adjustment ampere apparatus armature arrangement battery cable capacity centre charge compensation circuit condenser conductor connected current flowing current key Daniell cell deflection diameter difference of potential direction discharge disconnected double current duplex earth earthed battery effect electrical electromagnet employed equal fault fuse galvanometer gutta-percha holes inches indicated instrument insulation internal resistance iron joined key is depressed lead length lever mark method molecules negative number of cells obtained parallel passes path pipe placed plate pole position produced quadruplex R₁ received relay resistance coil result reversed rheostat screw secondary cell self-inductance short circuit shown in Fig shunt side signals single current sounder space speed standard cell station stay stress sulphate sulphuric acid switch spring tangent tangent galvanometer tape telegraph telephone terminal terminal station test box tongue transmitter tube type wheel U-circle volts Wheatstone Wheatstone bridge whilst wire zinc zinc sulphate
Popular passages
Page 36 - To secure purity it should be first treated with acid in the usual manner and subsequently distilled in vacua. 2. The Zinc. — Take a portion of a rod of pure redistilled zinc, solder to one end a piece of copper wire, clean the whole with glass paper, carefully removing any loose pieces of the zinc. Just before making up the cell dip the zinc into dilute sulphuric acid, wash with distilled water, and dry with a clean cloth or filter paper. 3. The Zinc Sulphate Solution. — Prepare a saturated...
Page 216 - The total resistance of a parallel circuit is equal to the reciprocal of the sum of the reciprocals of the individual resistances of the circuit.
Page 36 - Mix the washed mercurous sulphate with the zinc sulphate solution, adding sufficient crystals of zinc sulphate from the stock bottle to ensure saturation, and a small quantity of pure mercury. Shake these up well together to form a paste of the consistence of cream. Heat the paste, but not above a temperature of 30° 0.
Page 37 - Then insert the cork and zinc rod, passing the glass tube through the hole prepared for it. Push the cork gently down until its lower surface is nearly in contact with the liquid. The air will thus be nearly all expelled, and the cell should be left in this condition for at least...
Page 64 - Experiment proves that the resistance of a conductor of uniform gauge is directly proportional to its length and inversely proportional to its sectional area.
Page 36 - ... any free acid. The crystals should be dissolved with the aid of gentle heat, but the temperature to which the solution is raised should not exceed 30° C.
Page 37 - ... taking care that the whole of the exposed platinum is covered. Shake up the paste and introduce it without contact with the upper part of the walls of the test-tube, filling the tube above the mercury to a depth of rather more than 1cm.
Page 37 - The cell thus set up may be mounted in any desirable manner. It is convenient to arrange the mounting so that the cell may be immersed in a water bath up to the level of, say, the upper surface of the cork. Its temperature can then be determined more accurately than is possible when the cell is in air. In using the cell sudden variations of temperature should as far as possible be avoided.
Page 909 - ... Plant World, 2s. 6d. Mathematical Tables, Hutton, 12s. Mathematics, Elementary, Hatton, 2s. 6d. May's Ballooning, 2s. 6d. Maycock's Electricity and Magnetism, 2s.
Page 8 - The student should learn at least one rule for remembering the relation between the direction of the current and the direction of the magnetic flux.