Signalling through space without wires : being a description of the work of Hertz & his successors / by Oliver J. Lodge.

  • Oliver Lodge
Date:
[1900]
Catalogue details

Licence: Public Domain Mark

Credit: Signalling through space without wires : being a description of the work of Hertz & his successors / by Oliver J. Lodge. Source: Wellcome Collection.

Provider: This material has been provided by the Francis A. Countway Library of Medicine, through the Medical Heritage Library. The original may be consulted at the Francis A. Countway Library of Medicine, Harvard Medical School.

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    lined with tinfoil, to the outside of which the sending hat (Fig. 20) is fixed, and to pull the key of the primary exciting circuit by a string from outside, so that not even key connec- tions shall protrude, else exact optical experiments are impossible. Even then, with the lid of the hat well clamped on, some- thing gets out, but it is not enough to cause serious dis- turbance of qualitative results. The sender must evidently be thought of as emitting a momentary blaze of light which escapes through every chink. Or, indeed, since the waves are some inches long, the difficulty of keeping them out of an Fiq. 21.—General arrangement of experiments with the Copper Hat, showing Metal Box on a Stool, standing outside the Theatre. The Box is not exactly represented, but inside it the Radiators were fixed with a graduated series of apertures ; the Copper Hat containing the Coherer is seen on the Table with the Metal Box on the left of the Table containing Battery and Galvanometer Coil connected to it by a compo pipe conveying the wires, as in Fig. 19c ; the Lamp and Scale barely indicated at one side of the Table ; a Paraffin Prism ; and a Polarising Grid of copper wires stretched on a frame. [This figure is from a thumbnail sketch by Mr. A. P. Trotter, taken at the Lecture in 1894.] enclosure may be likened to the difficulty of excluding sound; though the difficulty is not quite so great as that, since a reasonable thickness of metal is really opaque. I fancied