The effects of Light on the Germination of Seeds. 539 



yellow glass, it has not on any occasion endured to the per- 

 fection of a flower. Excepting under the yellow and blue 

 glasses, all the plants experimented on have been more or 

 less etiolated. 



The results in those cases where fluid media have been 

 used, from the more perfect isolation of the rays which have 

 been thus obtained, have been much more decided. Under 

 the influence of the light which had been subjected to the 

 influence of the yellow fluid, germination has been entirely 

 prevented. Under the red light, in some cases, germination 

 has commenced, but the young plant has speedily perished. 

 Under the green, the plant has been developed, but in a very 

 weak state, with pale leaves, and nearly colorless stalks. But 

 under the influence of the blue light, the most perfect plants 

 have been produced, and through all their stages, maintained 

 in the most luxuriant state. 



These experiments prove that the process of germination 

 is obstructed by the influence of light on the surface of the 

 soil, although the bulbs and seeds have been buried some 

 depths beneath it. The effects of heat, as exhibited by the 

 red rays, are not, I think, to be regarded as destructive in 

 themselves ; as plants have been found to grow under the 

 influence of those rays when they have been supplied with 

 an extraordinary quantity of water, to supply that drawn off 

 by continued evaporation : whereas, although the evaporation, 

 which has been equally rapid under the yellow media, has 

 been met in the same manner as under the red, it has pro- 

 duced no beneficial results. 



One very remarkable result must also be here noticed. 

 Under all ordinary circumstances, plants incline decidedly 

 towards the light, as may be seen by placing any kind of 

 plants, in a common room, near a window. Thus, having a 

 very small portion of the surrounding space open to the 

 transmission of light, the plants will speedily turn the surface 

 of their leaves towards the medium by which light is ad- 

 mitted. This will also be the case should the plants be 

 placed at the extreme end of the room, many yards distant 

 from the window ; and when not influenced by the direct 



