Doubts concerning the inversion of objects on the retina / by Marmaduke Berdoe.

  • Marmaduke Berdoe
Date:
1772
Catalogue details

Licence: Public Domain Mark

Credit: Doubts concerning the inversion of objects on the retina / by Marmaduke Berdoe. Source: Wellcome Collection.

    78/98 (page 68)
    \ [ 68 ] i the rays of light expand by the property of that elaftic force which they conflantly pre- ferve, a;,I unfolding themfelves diverge to the fpace of ten degrees on the larger circle, from whence they purlue their primitive reftilinear courfe. The variation in the difpofition of the ob]e6t M N, at Q R, is the abfolute confequence of that change which the cone of rays have fuffer’d by the attraftive force of tlie fperical tranlparent medium E F G H, for we may obferve that no fuch change could happen in the polition of the obje6t if they were continued on without any interruption as at K L. It is likewife very elfential to our defign to re¬ mark again, that this inverlion in the po¬ lition of the obje6I cannot poffibly take place, or the rays of light diverge if they have not previoujly been collected into a focal point. 8thly. Now the true diltance of the focal point from any medium, is not to be de¬ termined by a general charaGer, for it is found to vary according to the form or #