A Simple Tester for a Conductor An ordinmy fluorescent lamp can be used to test whether a substance is a conductor or not. The arrangement is shown in the figure. The filament of the lamp is usually located about 4 em from the end of a 3-cm diameter lamp. The position of the filament should be marked by a copper wire or a metal strip, A , placed ootside of the glass tube (this is only to enable the observer to locate the filament in the dark). Then the lamp is set in a circuit with the switch off and the room is darkened. After the tester becomes accustomed to the darkness, he then simply presses the substance, B, being tested against the surface of A or the tube near A . If it is a conductor a faint glow will appear in the tube under A .
SHUKICHI YAMANA H l ~ l n uYAMANI HAJIMU YAMWA K v o m U N I V ~ S I OF TY EDUCATION
FUSHIMI-KU, KYOTO, JAPAN
