536 STUDIES IN ADVANCED PHYSIOLOGY. 



sists in neutralizing the yellow of the linen, yellow and 

 indigo forming white. 



Blue 



Fig. 164. GRAPHIC REPRESENTATION OF THE FORMATION OF WHITE OUT OF THE SERIES 



OF COMPLEMENTARY COLORS. 



The line frohi the green should be continued to the purple, as green and purple are 

 complementary colors. 



6. The Colors of Objects by Transmitted or Reflected 

 Light. So far the colors have been described as vibrations 

 of ether proceeding from a luminous body, and by the 

 number of such vibrations per second the light will have 

 its color determined. But most bodies are not luminous; a 

 window pane is not luminous but transmits light through 

 it ; the wall of a house is not luminous but is seen only by 

 the light which it reflects from some luminous source. 

 Ordinarily this transmitted or reflected light is sunlight. 

 Even though the rays of the sun do not shine directly into 

 the room, some of the rays have been reflected by the grass 

 or sky, or objects on the ground in such a way as to reach 

 the wall in question, and being reflected from this in turn 

 into the eye, the wall becomes visible. 



The question then presents itself, what determines the 

 color of such a transparent piece of glass or of the opaque 

 wall? 



First, objects colored by transmitted light. A red win- 

 dow pane seems red because it has absorbed all the other 

 colors in the light which passes through it, but transmits 

 unhindered the red light reaching it. Like the gold digger 



