338 ANNUAL OF SCIENTIFIC DISCOVERY. 



bonate of soda introduced into the paste, forming with its alkali a soluble 

 salt ; and the mealy substance, purified by a simple washing, is deposited 

 at the bottom of the vat whence you have gathered it. 



ON THE INFLUENCE OF THE SOLAR RADIATIONS ON THE VITAL 

 POWERS OF PLANTS GROWING UNDER DIFFERENT ATMOS- 

 PHERIC CONDITIONS. 



In a report on this subject, made to the British Association, by Mr. J. 

 H. Gladstone, the author commenced by describing accurately what por- 

 tions of the prismatic spectrum were cut off by the various colored glasses 

 employed in his experiments. A series of observations followed on 

 hyacinths grown under very varied influences of light, and solar heat, and 

 chemical agency. Among the results may be mentioned the power of the 

 yellow ray to diminish the growth of rootlets, and the absorption of 

 water ; the power of the red ray to hinder the proper development of the 

 plant ; and the effect of total darkness in causing a rapid and abundant growth 

 of thin, rootlets, in preventing the formation of the green coloring matter, but 

 not of that of the blue flower, nor of the other constituents of a healthy plant. 

 A series of experiments on germination was then detailed. Wheat and pease 

 had been grown without soil under large colorless, blue, red, yellow, ob- 

 scured colorless, and obscured yellow glasses, and in perfect darkness. The 

 effects resulting from these varied conditions were very marked. The two 

 plants experimented on being chosen from the two great botanical 

 divisions exhibited a wide diversity, sometimes amounting to a direct 

 opposition, in their manner of being affected by the same solar ray ; but 

 in the case of both the plants, under the circumstances of the experiment, 

 the following effects were observed : The cutting off of the chemical ray 

 facilitates the process of germination, and that both in reference to the 

 protrusion of the radicles and the evolution of the plume : the stem 

 grows unnaturally tall, and there is a poor development of leaves in dark- 

 ness, becoming more manifest as the darkness is more complete ; and the 

 yellow ray exerts a repellent influence on the roots, giving the wheat a 

 downward, and the pea-roots a lateral, impulse. Prof. Miller, in thanking 

 the author for his valuable researches, made some remarks on the interest- 

 ing results that the investigation had brought to light, and drew especial 

 attention to the remarkable fact stated in the paper, that the blue rays re- 

 tarded the action of germination at first, although they probably accelerated 

 the growth of the plant afterwards, the act of germination being attended 

 with absorption of oxygen, but the process of development being, on the 

 contrary, attended with the extrication of this gas. Prof. Anderson re- 

 marked, that a similar difference in the rate of growth of the leguminous 

 plants and grasses to that described by Mr. Gladstone had been observed 

 when they were manured with the same material. Nitrate of soda, which 

 was found to be an excellent fertilizer for grasses, had comparatively little 

 influence upon leguminous plants. 



