Key points are not available for this paper at this time.
illuminations before solidity was clearly perceived.Thus the reliability of the statement that the perception of solidity occurs in the instant of illumination by an electric spark appears doubtful.The positive after- image would also be a factor here.No one so far as I can find has hitherto suggested that retinal rivalry plays an important part in the perception of solidity, but from the evidence presented.inthis paper such a conclusion seems probable.
Farnsworth et al. (Tue,) studied this question.