The cathode ray tube had just been fitted with a hot cathode,which permitted operation at 300 volts instead of the previously required 10,000,the lower voltage obtainable from a stack of dry cells of less than ceiling height.

• （那时）刚刚有用一种热阴极作成的阴极射线管，这种热阴极不需要以前要求的10，000伏，可以在300伏电源下工作，这种低电压可以由不再堆得天棚高那末多的干电池来获得。