Abstract :
In the past the photoelectric cell has been adapted to photometry with varying degrees of success, but in almost every instance the apparatus required in such an adaptation has been too sensitive in its operation to make it readily usable in the commercial laboratory where speed and ease of operation are as important as accuracy, but this new method of photoelectric photometry bids fair to become widely used in the photometric laboratory. In the adaptation of the photoelectric cell to the commercial laboratory there are several difficulties to be overcome. The first of these concerns the fact that no form of photoelectric cell yet produced has the same color-sensitivity curve as the eye. Therefore, of two lights of different color which the eye might evaluate as being of equal intensity, the cell would show the whiter light to be of the higher intensity. This difficulty is almost entirely eliminated through a comparison between two lamps of the same color.
