. . "Explains the psysiology of the human eye, showing how it is used to perceive shapes, colors, shadows and reflections. Includes simple experiments."@en . "Sight"@en . "Sight" . . . . . . . . . . "Juvenile works" . . . "Juvenile works"@en . . . . "Explains the physiology of the human eye, showing how it is used to perceive shapes, colors, shadows and reflections. Includes simple experiments."@en . "Explains the physiology of the human eye, showing how it is used to perceive shapes, colors, shadows and reflections. Includes simple experiments." .