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choose the connection indicated diagrammatically in Fig. 5, as in this case the currents forming the arc are much more powerful, and the magnetic field exercises a greater influence. The use of the magnet permits, however, of the arc being replaced by a vacuum tube, but I have encountered great difficulties in working with an exhausted tube.
Fig. 5.—Arrangement with Low-Frequency Alternator and Improved Discharger.
The other form of discharger used in these and similar experiments is indicated in Figs. 6 and 7. It consists of a number of brass pieces c c (Fig. 6), each of which comprises
Fig. 6.—Discharger With Multiple Gaps.
a spherical middle portion m with an extension e below—which is merely used to fasten the piece in a lathe when polishing up the discharging surface and a column above, which consists of a knurled flange f surmounted by a threaded stem l carrying a nut n, by means of which a
