An essay upon single vision with two eyes : together with experiments and observations on several other subjects in optics / by William Charles Wells, M.D.

  • Wells, William Charles, 1757-1817.
Date:
1792
Catalogue details

Licence: Public Domain Mark

Credit: An essay upon single vision with two eyes : together with experiments and observations on several other subjects in optics / by William Charles Wells, M.D. Source: Wellcome Collection.

Provider: This material has been provided by University of Bristol Library. The original may be consulted at University of Bristol Library.

    36/156 (page 28)
    pffing from its picture on the retina, through the centre of the eye. If, there- fore, this direction be the fame as that fug- gefled by the original property fo often mentioned, the latter law is merely another expreffion for the former, and ought to be rejected as fuperfluous. If it be different, and mould the two laws exift together, objects feen with both eyes mightfometimes appear quadruple, fometimes triple, but never tingle. Were they to exift fuccef- iively, one when we employ one eye, the other when both, an object, though at reft, mould always appear to move when viewed alternately by one and by both eyes ; nei- ther of which conclufions is agreeable to experience. Thirdly ; To mow in a different way, and one perhaps more eafily underftood, that the opinion of Dr. Reid is not confident with the phenomena of vifion it oughtj to explain, I mall fuppofe an experiment to be made upon a perfon who fquints. But I muft premife, that it appears, from the c obfervations