. British and Foreign Medical Review; or, Quarterly Journal of Practical Medicine and Surgery. een single, though it is to be remarked not exactly resemblingeither of the two pictures on the retinae. It being thus established, says Mr. W. (p. 373), that the mindperceives an object of three dimensions by means of the two dissimilarpictures projected by it on the two retinas, the following question occurs:What would be the visual effect of simultaneously presenting to eacheye, instead of the object itself, its projection on a plane surface as itappears to that eye ? For this purpose Mr. Wheatsto
. British and Foreign Medical Review; or, Quarterly Journal of Practical Medicine and Surgery. een single, though it is to be remarked not exactly resemblingeither of the two pictures on the retinae. It being thus established, says Mr. W. (p. 373), that the mindperceives an object of three dimensions by means of the two dissimilarpictures projected by it on the two retinas, the following question occurs:What would be the visual effect of simultaneously presenting to eacheye, instead of the object itself, its projection on a plane surface as itappears to that eye ? For this purpose Mr. Wheatstone invented an instrument which hecalls a stereoscope. It consists of two plane mirrors, with their backsinclined to each other, at an angle of 90°, near the faces of which thetwo monocular pictures are so disposed, that their reflected images are seenby the two eyes, each looking into one of the mirrors, in the same place. The observation may be sufficiently well made by viewing the subjoinedfigures,—the dissimilar perspectives of a truncated four-sided pyramid,in the following manner:. the right eye on the right-hand figure, and the left eye on theleft-hand figure, hold between the eyes in front of the nose the board ofan octavo book. The two figures will be seen to approximate, and thenrun mto one representing the skeleton of a truncated four-sidedpyramid in bold relief. Were the theory of corresponding points true, Mr. Wheatstoneremarks (p. 392), the appearance should be that of the superpositionof the two drawings; to which, however, it bears not the slightestsimilitude. ° The above experiment is decisive in the disproof of the doctrine as 1840.] on the Anatomy, Physiology, and Diseases of the Eye. 19 stated by Alison, that images formed on corresponding points, and onthose only, naturally affect our minds in the same manner as a singleimage formed on the retina of one eye, but we cannot admit witli tliat it disproves the doctrine of corresponding p
Size: 1567px × 1595px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade183, bookpublisherlondon, bookyear1839
