Atkinson, Philip. [from old catalog] · New York, The Century co. · leaf 251
he two disksbeing such that rays collected bythe cathode, acting as a concavereflector, are focused on the anode.The tube, or bulb, is exhausted to the usual high degree of vac-Fig. 101. . & 8 uum mentioned on page 42; the best vacuum for this special purpose being carefully de-termined by…
Electricity
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