310 Inslilute of France. 



city ill the galvanic series, attributed by Sir H. Davy to induction ^ 

 was conceived to be not founded upon any known law of electri- 

 city : in all cases of induction, the intensity induced is never 

 greater than that of the inducing cause ; and this was illustrated 

 by various experiments. Numerous objections were made to 

 this explanation; amongst others it was stated that the princi- 

 ple of induction is unnecessary, that it cannot operate, that if it 

 did it would not explain the phaenomena, that it excludes the 

 fitate of electric neutrahty known to exist in the middle of the 

 pile. It was also objected, that although the hypothesis con- 

 ceives the separation of the differently electric elements of the 

 taline solution interposed in tlie series to depend on the difference 

 of electric state in the metals, yet the same separation is effected 

 in cases where experiment proves that negative electricity is not 

 present. Considerations were also adduced, which seemed to 

 show that neither positive nor negative electricity acts any part 

 in the separation of the combined elements. 



In the hypothesis of Davy, water is assumed to be an insula- 

 tor: and upon this question rest the claims of the whole, \'a- 

 rious experiments were stated, designed to prove that water is 

 a very perfect conductor of low intensities, and whenever it is an 

 imperfect conductor,, that it is only to tlie higiiest intensities. - 

 But whether water be or be not an insulator, the result was sup- 

 posed to be equally unfavourable: if its insulating power be de- 

 nied, every principle of this doctrine is subverted ; if admitted, 

 it opposes some of the facts which it was intended to explain. 

 Various other imperfections of Sir H. Daw's views were noticed; 

 and this part of the essay concluded with some general remarks 

 on the contradictory nature of the fundamental principles of 

 galvanic hypotheses. 



[To be coiitiiiu^f!.] 



FRENCH INSTITUTE. 

 [Continued from p. 23'2.] 



M. Augustus St. Hilaire, whose papers on Botany have been 

 frequently mentioned, has this year made some observations on 

 several families of plants, in which xhe placenta, i. e. the part of 

 the fruit to which the seeds adhere, is simple, and placed in the 

 midst of the fruit like a column on an axis. 



When the summit of this column is free, the route by which 

 the influences of the pollen are transmitted from the pistil to the 

 seeds seems to be sufficiently complicated, and is formed by 

 vessels which creep alo;;g even tlie sides of the fruit, in order to 

 penetrate into the placenta by its I)ase, and proceed to the seeds 

 side by side with the iiutritivc vessels. Such is in fact the pro- 

 gress 



