O. N. Rood on the Perception of Distance and Color. 185 
(3.) With the erecting or inverting telescope, in proportion as 
the objects viewed are divested of the idea of solidity or depth, 
can their more delicate tints be perceived. Objects, which in 
normal vision seem to us nearly without color, are best fitted for 
these observations; a bare pile of stones an ry mud viewed 
ena a telescope appears often like a richly tinted water color 
Tawing. 
It would seem probable that if we could add to paintings of 
landscapes the element of distance, the mind occupied with tbis 
would no longer dwell on the richness of the tints. In confir- 
mation, I find that colored stereographs of landscapes, which out 
of the stereoscope seem exaggerated in tint, when placed in the 
instrument no longer appear too highly colored. 
rom the foregoing considerations, then, it would appear that 
when the mind is engaged with the perception of distance, the 
Presence of color is often overlooked ; its absence may remain un- 
noticed from the same cause, for in uncolored stereographs of 
objects that are perfectly familiar to the observer, it will some- 
e 
few or no traces of pink or flesh color—but every one who has 
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when seen inverted upon the screen in a dark chamber. re 
the neutral tints which in nature are almost unnoticed by the 
common observer, stand out as distinct patches of color in the 
Way so well described by Prof. Rood.—s.] 
AM. Jour. Sc1.—Snconp Series, VoL. XXXII, No. 9,—Serr., 1861. 
24 
