306 DETAILED SYNTHESIS. 



825. THE EYE is REPOSED TEMPORARILY by receiving 

 different kinds of light in succession, or if all three kinds 

 act together, by not receiving any for an instant. 



826. Inf. Black and white are the best colors for a reading-book 

 (and black letters upon a white ground are better than white letters on 

 a black ground would be), since the retina that corresponds to black is 

 perfectly rested, and that acted upon by white has the influence of all 

 colors at once ; while any other colors would give constant activity to 

 the retina. The proportion of white and black should be better adjust- 

 ed in school-books than is usual, through an incorrect idea of cheapness. 

 What injures the eyes is never cheap. 



827. Inf. THE ART OF PLEASING THROUGH THE EYE consists in pre- 

 senting before it a succession of colors, the aggregate of which will be 

 white. The complexion, clothing, adornments, furniture, and every- 

 thing colored must be arranged upon this principle. 



828. Illus. A moss rosebud pleases, because its red and green 

 are in proper proportions. A Violet (Viola tricolor), five sixteenths yel- 

 low and eleven sixteenths purple, will please, their proportions being 

 right. Blue is becoming to blondes, because in their hair and complexion 

 orange predominates, which with blue produces white. 



829. THE RETINA is SOMETIMES BLIND entirely, and 

 sometimes to only one or two kinds of light, when it is 

 called color-blind. Sometimes one eye is blind to one 

 color and the other to another. 



830. THE AUTHOR HAS SEEN a person who recognized 

 a green object as blue with one eye and yellow with the 

 other, one eye being blind to blue, the other to yellow. 



831. BLINDNESS is SOMETIMES PRODUCED by an im- 

 perfection in the character of some of the Media of the 

 eye. This blindness is of three classes: 1st, want of 

 transparency ; 2d, too little, and 3d, too great, refractory 

 power. 



832. THE MEDIUM THAT is WANTING IN TRANSPAR- 

 ENCY can sometimes be removed, and its place supplied 

 with a glass that will, in a measure, restore sight. 



833. LONG SIGHT is PRODUCED either because the 

 Media of the eye are not sufficiently convex, or because 



825. How is ? 826. What best colors for reading? 827. What is - ? 829. Is 

 ? 880. What has ? 881. How is ? 882. What said of ? 833. How is f 



