In many cases additional condensers or inductance coils are inserted in various places so that the arrangement is somewhat disguised, but by far the larger part of the electric wave wireless telegraphy in 1907 was effected by transmitters having antennae either inductively or directly coupled to a closed condenser circuit containing a spark gap.
In the case of transmitters constructed as above described, in which the effective agent in producing the electric waves radiated is the sudden discharge of a condenser, it should be noticed that what is really sent out is a train of damped or decadent electric waves.
With wireless telegraph transmitters, in which the oscillatory discharge of a condenser is used to create oscillations in an antenna, labours under the disadvantage that the time occupied by the oscillations is a very small fraction of the total time of actuation.
Such multiple-electrode transmitters give a loud although somewhat harsh sound, and will bear being spoken to very strongly without breaking the circuit.
50) embodies the idea of supplying current to the transmitters over the line wires in parallel instead of round the loop circuit, as in the other systems referred to.
The impedance coils shown connected between the battery and the lines and between the latter and the transmitters are joined up non-inductively as regards the transmitter circuits, but inductively as regards the secondary circuits.
On the other hand, those substances which either are good reflectors or good transmitters, are not so luminous at the same temperature; for instance, melted silver, which reflects well, is not so luminous as carbon at the same temperature, and common salt, which is very transparent for most kinds of radiation, when poured in a fused condition out of a bright red-hot crucible, looks almost like water, showing only a faint red glow for a moment or two.
The great schoolmen were transmitters - putting in order, stating clearly and consecutively, conclusions reached by wiser and holier men in earlier times.