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.

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    obfervations of Dr. Jurin * and hirrir felf, f that all fuch perfbns have one eye of a weaker fight than the other; that when both eyes are open, the weaker is turned away from objects, which are atten- tively viewed ; but that when the ftrong eye is clofed, the weaker is pointed to ob- jects, exactly as the former would be in the fame fituation and that it likewife per- ceives them in limilar directions. Let now the ordinary pefition of the perfon's eyes, up- on whom the experiment is made, be fuch, that the optic axes interfect each other about an inch or two from the face; and while the other is clofed, let the flame of a candle be placed in the axis of the weak eye, which I mail call the left, at the diftance of fome feet from it, and on the right fide of the body. The flame will confequently appear in the fame direction, as if his eye had no fault, and will befeen'on. his right, where it is in reality fituated. Both eyes retaining the fame pofition with refpect to his head and each other, let the weak ? Smith's Optics. Vol. 2. Remarks, p. 30. -j Inquiry, cti3p. 6. feft. 16.