In order to determine the amount of over shooting, the writer has made photographs as shown below. Number one was made with the lamp under voltage, number two by using normal voltage and suddenly turning the lamp on by means of a snap switch, thereby obtaining the overshooting, and finally number three was made by impressing voltage above normal. The pictures were obtained by using the photographic arrangement as before described. All three prints were made from the same film, that is the three pictures were made upon one film thus insuring the same development and printing for all. The print has been cut merely to allow a closer comparison of the intensities.

It is seen that number three compares favorably with the overshooting as shown by number two and the candle power corresponding was found to be approximately 50% greater than normal. It is not claimed that every lamp will overshoot this amount as the degree of vacuum or other factors of individual lamps may play an important part in this phenomenon. There is no doubt, however, that this strange fact really occurs and is not due to physiological reasons.