Since the introduction of the tungsten lamp some five years ago, the manufacturers have attempted continually to produce smaller and smaller units in the standard voltages. The latest lamp offered today is the 115 volt, 15 watt, tungsten, and it is the purpose of this paper to show the characteristics of this lamp, how it compares with the larger units as to life under different conditions and its behavior in general.

First of all, it must be borne in mind that these tests have been made upon a comparatively small number of lamps, and for that reason the results should not be taken as absolutely conclusive. For the life tests, at least 100 lamps should have been used under each condition, but this was impossible because of the expense.

Special attention has been given to the phenomenon of “overshooting”. An entire year could have easily been spent investigating this subject, and the writer regrets that lack of time has prevented more elaborate and comprehensive tests of this strange phenomenon.