The coil is encased with firebricks and brickwork, and the smoke from the fire is carried, off by a flue in the ordinary s " way.
Direct radiators are a development of the early coil of pipe; they are made in various types and designs and are usually of cast iron.
To each radiator should be fitted an air tap, which when opened will permit the escape of any air that has accumulated in the coil; otherwise free circulation is impossible, and the full benefit of the heat is not obtained.
Water may also be heated by placing a coil of steam or high-pressure hot-water pipes in a water tank (fig.
4); a current is sent from a battery, E, through one coil of a galvanometer, g, through a high resistance, r, through one of the wires, r, and thence back from office B (at which the wires are looped), through wire 2, through another high resistance, r', through a second coil on the galvanometer, g, and thence to earth.
The deflection observed on the galvanometer when the lines are leaky is d, while D is the deflection obtained through one coil of the galvanometer with all the other resistances in circuit; and assuming that no leakage exists on the lines, this deflection is calculated from the " constant " of the instrument, i.e., from the known deflection obtained with a definite current.
A key K to one end of the coil of the relay magnet R, II the other end of which is put to earth.
In order to avoid this sparking, every local instrument in the British Postal Telegraph Department has a " spark " coil connected across the terminals of the electromagnet.
Incoming currents pass from line through one coil of the relay, the key, and either the battery or battery resistance, according as whether the key is raised or depressed.
The indicator was connected with a Ruhmkorff coil or other equivalent apparatus, designed to cause a continual succession of sparks to pass between the indicator and a metal plate situated beneath it and having a plane surface parallel to its line of motion.
The magnet between the poles of which the rectangular signal coil moves is built up of a number of thin flat horseshoe-shaped permanent magnets of a special quality of steel, and is provided with adjustable pole pieces.
The signal coil is suspended by fibres and is mounted together with a fixed soft iron core on a brass plate affixed to a rack, with which a pinion operated by a milled head screw engages.
The recorder coil is connected mechanically to a second similar coil, which is suspended between the poles of a laminated magnet, so that the motions of the two are similar.
The use of the iron core renders it possible to produce a high inductive effect with a low resistance coil.
Sending current enters an adjustable mid-point in the g coil and passes through the two halves of the winding to the ends connected to the cable and artificial line respectively.
The average total inductive value of these bridges to received signals is about 40 henrys, and the coil is so arranged that the arms contain three sections or blocks of winding each, two of which are joined up to strap connexions, and the a p :?; .?
If a primary circuit, consisting of a large coil of wire P (fig.
Thus, in the case of one station and one moving railway carriage, there is a circuit consisting partly of the earth, partly of the ordinary telegraph wires at the side of the track, and partly of the circuits of the telephone receiver at one place and the secondary of the induction coil at the other, two air gaps existing in this circuit.
In circuit with this battery was placed the secondary circuit of an induction coil, the primary circuit of which contained a telephone transmitter or microphone interrupter.
In conjunction with the above receiver he employed a transmitter, which consisted of a large induction or spark coil S having its spark balls placed a few millimetres apart; one of these balls was connected to an earth FIG.
The antenna wire, connected to one spark ball of the induction coil, must be considered to form with the earth, connected to the other spark ball, a condenser.
These trains are produced by pressing the key in the primary circuit of the induction coil for a longer or shorter time' and generating a long or short series of oscillatory electric sparks between the spark balls with a corresponding creation of trains of electric waves.
Instead of inserting the sensitive tube between the receiving antenna and the earth, he inserted the primary coil of a peculiar form of oscillation transformer and connected the terminals of the tube to the secondary circuit of the transformer.
There are three ways in which the antenna may be charged (i) It may be separated from the earth by a pair of spark balls which are connected respectively to the terminals of an induction coil or transformer, or other high tension generator.
In the early experiments Marconi connected the sensitive tube in between the receiving antenna and the earth plate, but, as already mentioned, in subsequent forms of apparatus he introduced the primary coil of a peculiar form of oscillation transformer into the antenna circuit and connected the ends of the sensitive tube to the terminals of the secondary circuit of this " jigger " (fig.
Rutherford examined it very carefully, and produced a magnetic detector for electric waves depending upon the power of electric oscillations in a coil to demagnetize a saturated bundle of steel wires placed in it (see Phil.