400 Scientific l7itelligence. — Botany. 



self of this a priori ; and what theory points out in this mat- 

 ter, experience confirms. The most expert observers of Paris 

 have long remarked, that objects which are distinctly seen with 

 the vertical achromatic microscope, are not perceptible with 

 Amici's microscope, and more than one observer has already re- 

 pented of having sacrificed the former, for the expensive agate 

 of the latter. — Le Globe. 



18. On the Organization of the genus Char a, — There was 

 read to the Academie des Sciences of Paris, on the 21st July 

 1828, a letter from M. Raspail, respecting the organization of 

 the genus Chara. Botanists and Natural Philosophers have 

 hitherto been much puzzled by the existence of two opposite 

 currents of green matter, in the interior of the tubes of this ge- 

 nus, which never intermingle, although there is no partition be- 

 tween them. M. Raspail gives a very simple explanation of this 

 singular phenomenon. " Having brought near the flame of a 

 lamp,'" says he, " a tube closed at one end, and filled with alco- 

 hol, holding a multitude of globules of fat in suspension, I soon 

 observed a current of globules proceeding upwards on one side, 

 and again descending on the other, to continue the same motion 

 without intermission. So long as I kept the tube at the same 

 temperature, the two currents never mingled ; and, during the 

 whole continuance of the experiment, there existed a visible line 

 of demarcation between them. In a word, my glass-tube was 

 an exact representation of the tube of a chara, which is, in fact, 

 nothing but a transparent tube closed at both ends, lined with a 

 layer of green matter, and in which there are distinguished an 

 ascending and descending current." M. Raspail produced a 

 glass-tube containing sawings of wood, of which it was sufficient 

 to heat the base with the hand, to produce the phenomenon. 

 The two currents were quickly established after a ^ew oscilla- 

 tions. Then followed, in the letter, the physical explanation 

 of the phenomenon. In reahty, in the chara, it is not the heat 

 that determines the twofold motion, but the aspiration and ex- 

 piration of water operated by the tube, as M. Raspail has al- 

 ready demonstrated. The phenomenon in question has also 

 been produced by him in glass-tubes, by means of an artificial 

 aspiration and expiration. — Le Globe, 26. Juillet 1828. 



19- Account of a new Species of Pinus, a native of Calif or- 



