The authors have developed a new apparatus, based on the reading of E optotypes, in order to measure contrast sensitivity simply. Optotypes of six sizes and with seven different contrasts each are presented to the patient. The normal values measured with this apparatus show little variation and...
These relationships, which depend on the nature of the pistons, the quenched alloy and the sample thickness, agree with experiment. It is further shown that the thickness of the quenched platelets is always larger than a `critical value' attained in an `ideal' process. In such a process the...