The effects of Light on the Germination of Seeds. 399 



dium is remarkably transparent. The blue, green, yellow 

 and orange, rays freely, all the others being absorbed. 



'* This experiment is perfectly in accordance with the 

 effects of green glass on plants that are grown beneath its 

 influence, as we shall endeavor to shoAV in a subsequent 

 article." 



D. Blue. — Cupro- Sulphate of Ammonia. This fluid ob- 

 literates all the rays below the green rays, those above per- 

 meating it freely. 



E. White. — This is merely water rendered acid by nitric 

 acid, for the purpose of securing its continued transparency. 

 It should be noticed that spaces in the boxes have been left 

 open to the full influence of the light, that a fair comparison 

 might be made between those plants growing under ordinary 

 circumstances, and the others under the dissevered rays. 



It will be seen from the above that the following combina- 

 tions of rays have been obtained to operate with : — 



A. — 1. The calorific rays well insulated. 2. A smaller 

 portion of these rays, mixed with a small amount of those 

 having power of illumination. 3. The luminous and calo- 

 rific rays combined. 4. The calorific rays and the chemical 

 ones blended together. 



B. — The luminous rays, in a tolerably unmixed state. 

 C. — The luminous rays, combined with the least actively 

 chemical ones. But in this case the luminous rays exert 

 their whole influence. 



D. — The most refrangible rays well insulated. 

 E.— White light. 



From these arrangements it will be evident that, although 

 we do not secure the complete isolation of the rays, as we 

 should do with a prism, we procure light, in which the great 

 preponderance of one influence over another suffices to en- 

 sure to a certain extent, the divided action of that one. We 

 are well aware that we only arrive at approximations to the 

 truth by this system. But they are sufficiently accurate to 

 show practically the action of light, when permeating the 

 different colored media, on vegetation subjected to its in- 

 fluence. 



