SEED-SOWING. 21 



incl violet a re the best colors. This will also apply to cut- 

 tings ; a bell glass of either color is preferable to white, for 

 the light forced through the prism is separated into differ- 

 ent colors, and experience has proven that glass possesses 

 the most powerful chemical action in promoting seed to 

 germinate. As I said before, in the first stage of germina- 

 tion, light is not so essential, though if sown too deep of 

 course the light is too much excluded and the necessary 

 nourishment is exhausted before the seed could reach the 

 light ; therefore deprives the function so essential from per- 

 forming the development of leaves, which are indispens ible 

 to the production of roots, and often perish or remain dor- 

 mant ; turning over the ground often brings the seed with- 

 in the desired range, and the pumuli ascending reaches the 

 light and germination takes place growth is best promot- 

 ed when covered with glass. The influence of light and 

 moisture then preserves uniformity more congenial. 



M. Chevreal, a French chemist, has demonstrated many 

 interesting facts in regard to colors contrasted and their ef- 

 fects. There has been some experiments made in England 

 in regard to colored glass, and it is proven there that violet 

 and blue are called chemical rays ; green and yellow, lu- 

 minous ; red, caloric or heating rays-. The illustrations are 

 not exactly correct. Light penetrating through colored 

 glass partakes, in some respect, of the character of the rays 

 corresponding with the colors of the glass ; as blue admits 

 of the chemical rays to the exclusion of nearly all others ; 

 yellow admits only the permeate of the luminous rays; 

 that red glass cuts the rays of heat which passes freely. By 

 this means it appears that plants could be raised under al- 

 most any light wished for ; while yellow and red are de- 



