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 V zgetables, 

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

 Academy, vol. 8, p. 960. 



