"Vacuum tube" Quotes from Famous Books
 ... still it by no means can be said that by means of the flaming arc lamp the color factor is under perfect control. However, it is possible now to have the color value under perfect control, and this is obtained by utilizing a vacuum tube, and by changing the various gases used in the tube to change the color. This has many advantages, and from a scientific standpoint it cannot be criticised, as can the other methods which have been used. ...
— Color Value • C. R. Clifford |
