PjivCEEDlMiS OF THE PoLFTECHMC A SSOVIATlny. ^59 



and nitrogen. In a suiaH poiul where a dense irrowtli ot' Leruna 



'&^ 



pon 



minor had been allowed to accumulate, and which under the influ- 

 ence of light decomposed the carbonic acid of the air and furnished 

 oxygen to the fish, it was found on excluding the light that both fish 

 and plants were killed. A distinguished French botanist, M. Yan 

 Tieghem, has also made some interesting experiments with aquatic 

 plants. He found that, although direct sunlight only is competent 

 to start the decomposition of carbonic acid by the chlorophyl of the 

 leaf, the plant continued to exert chemical action for three hours after 

 direct sunlight had been withdrawn, and for nine hours in difiused 

 daylight instead of darkness. From this he infers that the vibrations 

 induced by the luminiferous ether, or, in other words, by sunlight, 

 are continued in the chlorophyl after the withdrawal of the direct 

 rays, exciting a condition resembling that of solar phosphorence in a 

 solid, for instance, that of a diamond, which, after being exposed to 

 the direct rays of tlie sun, will emit a feeble light in the dark; and 

 tliat this action of the chlorophyl, when once commenced, may be 

 kept up by the modified motion of diffused daylight. The reasoning 

 of this botanist is plausible, but his premises are defective, since 

 plants will grow in acjuariuins which only receive the influence of dif- 

 fused daylight. 



Electkioity, Retukn to the Old Thei>ry. 

 Mr. Edward E. Quindjy, of this city, has published a very able 

 defense of Dr. Franklin's theory of static electricity, which attributes 

 this class of phenomena to an excess or a deficiency of a single 

 highly attenuated fluid permeating all ponderable matter. Objections 

 early made to this theory gave rise to the hypotliesis of two subtle 

 fluids, which was generally accepted by European electricians, but 

 which involves objections quite as serious as those it was intended to 

 obviate. Xot many years since scientists ascribed certain classes of 

 phenomena solely to the presence of difl'erent kinds of subtle matter, 

 and, at one period, not less than six distinct "imponderable fluids '' 

 were required to account for light, heat, electricity, magnetism and 

 gravitation. After the experiments of Fresnel had confirmed Iluy- 

 ghen's theory of light. Xewton's corpuscular theory was nu longer 

 tenable; and now the recei\X'd doctrine is that very diftei-ciit eftects 

 may be produced by the same kind of ethereal matter when in difl'er- 

 ent states or degrees of motion. Light, heat and actinism are sup- 

 posed to be generated through one medium by transverse vibrations 



