88 



after a passage of 180 feet, in the ratio of 1* to 

 1477*8. The sea- weed of L'Alegranza conse- 

 quently presents a new example of plants, which 

 vegetate in a great obscurity without being 

 whitened. Several germs, still enveloped in the 

 bulbs of the lily tribes, the embryo of the mal- 

 vacese, of the rhamnoides, of the pistacea, the 

 viscum, and the citrus, the branches of some 

 subterraneous plants ; in short, vegetables trans- 

 ported into mines, where the ambient air con- 

 tains hydrogen, or a great quantity of azote, 

 become green without light. From these facts, 

 we are inclined to admit, that it is not only un- 

 der the influence of the solar rays that this car- 

 buret of hydrogen is formed in the organs of 

 plants, the presence of which makes the paren- 

 chyma appear of a lighter or darker green, ac- 

 cording as the carbon predominates in the mix- 

 ture 



Mr. Turner, who has so well made known the 

 family of the seaweeds, and many other celebrat- 

 ed botanists, think that the greater part of the 

 fuci which we gather on the surface of the ocean, 

 and which from the 23d to the 35th degree of 



a tint of green by the vivid light of two lamps of Argand. 

 See also Lambert, Photometria, p. 223. 



* These ideas are in part explained in my memoir on the 

 phenomenon of etiolation (Journal de Physique, t. 40, p. 154) 

 and in my Aphorisms on the chemical physiology of Vegetables, 

 (Flora Freibergensis, p. 179) . See also Trans, of the Irish 

 Academy, vol. 8, p. 960. 



