Production and application of light

W. E. Beaty (Cincinnati): The application of individual motor drive to varied machines, and particularly to the machines requiring 5 h. p. and below, has introduced the need for indicating lamps in connection particularly with automatic control of such machines. The gaseous lamp shown may meet that problem, and I should like to ask Mr. Millar what the voltage limitations are on a lamp of that character? I am wondering if the lamp can be used on all circuits up to, say, including 550 volts?