An Opake Body will appear to have less Re lievo, as it is further distant from the Eye. This is owing to the Air, found between the Eye, and the Opake Body; which being brighter than the Shadow of the said Body, weakens the force, and diminishes the obscurity of that Shadow; tinging it, with its own Light, and adulterating it with its Azure; whence, of course the Body loses its Relievo.