Nikola Tesla - Free-Energy Devices

HIGH FREQUENCE: AND HIGH POTENTIAL CURRENTS. 307When the current through the gap is comparatively large, it isof advantage to slip on the points of the discharge rods pieces ofvery hard carbon and let the arc play between the carbon pieces.This preserves the rods, and besides has the advantage of keepingthe air space hotter, as the heat is not conducted away asquickly through the carbons, and the result is that a smallerE. M. F. in the arc gap is requiredto maintain a succession ofdischarges.Another form of discharger, which may be employed with advantagein some cases, is illustrated in Fig. 167. In this formthe discharge rods d d^ pass through perforations in a woodenFIG. 107.box B, which is thickly coated with mica on the inside, as indicatedby the heavy lines. The perforations are provided withmica tubes m m^ of some thickness, which are preferably not incontact with the rods d d . {The box has a cover c which is alittle larger and descends on the outside of the box. The sparkgap is warmed by a small lamp I contained in the box. A platep above the lamp allows the draught to pass only through thechimney of the