. Annual report of the Board of Regents of the Smithsonian Institution. Smithsonian Institution; Smithsonian Institution. Archives; Discoveries in science. Fig. Ic -Oscillation valve (Fleming) That the action is not altogether due to the removal of polarization films is shown by the fact that the fine platinum wire in the Schloe- milch form of detector wears away or is dissolved in the nitric acid when oscillations are passed for some time through the cell, and there is some evidence that gold and platinum can be made to dissolve even in dilute acids by the action of electric oscillations. In
. Annual report of the Board of Regents of the Smithsonian Institution. Smithsonian Institution; Smithsonian Institution. Archives; Discoveries in science. Fig. Ic -Oscillation valve (Fleming) That the action is not altogether due to the removal of polarization films is shown by the fact that the fine platinum wire in the Schloe- milch form of detector wears away or is dissolved in the nitric acid when oscillations are passed for some time through the cell, and there is some evidence that gold and platinum can be made to dissolve even in dilute acids by the action of electric oscillations. In 1904 I was so fortunate as to dis- cover another and quite different prin- ciple on which a sensitive electric wave detector can be based. If a carbon filament glow lamp has a metal plate carried on a third terminal sealed into the bulb, it is well known that a cur- rent of negative electricity flows from the plate to the positive terminal of the lamp, when the filament is ren- dered incandescent by a continuous current. This is the so-called Edison effect. It is also now known that in- candescent bodies discharge negative corpuscles or electrons from their surface, and incandescent carbon, when in a vacuum, exhibits this power in a marked degree. Negative electricity escapes freely from it, but not positive. In 1904 I was endeavoring to find some way of recti- fying electric oscillations, that is, of separating out the two sets of alternate currents and making them separately detectable by an ordinary galvanome- ter. It occurred to me to make use of a carbon fila- ment lamp, having a metal cylinder insulated in the bulb surrounding the fila- ment, the cylinder being connected to a platinum wire sealed through the bulb. (See fig. 13.) This lamp was then used as follows: A circuit was connected between the terminal of the metal plate and the negative terminal of the filament, the latter being made. Fig. 14.—Oscillation valve or glow lamp detector, used as a receiver in electri
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