As a result of the improvements made in the Faraday Effect Apparatus as described, our results indicate an attainable precision of ±0.02 percent for visual measurements. Comparing this value with those reported by other investigators, indicates that a definite increase in precision has been achieved. As soon as our method for making measurements photoelectrically is fully developed, it is expected that the precision will be still higher. This will be especially true in the shorter wave‐lengths where the eye is insensitive, and also where eye fatigue in general would be eliminated.