578 Intelligence and Miscellaneous Articles. 



oscillations are thereby rendered longer and slower, so that between 

 two consecutive returns of the pendulum to the starting-point, a 

 sensible deviation towards the left becomes clearly perceptible."— r 

 Bibliotheque UniverseUe de Geneve, Mars 1851. 



ON THE ELECTRIC CURRENTS WHICH EXIST IN VEGETABLES. 

 BY PROF. E. WARTMANN. 



For the two last years I have been engaged in the investigation of 

 the various physical phsenomena connected with vegetation, and I 

 have communicated at several meetings of the Societe de Physique 

 et d'Histoire Naturelle of Geneva the results. The principal sub- 

 jects of my observations were the influence of atmospheric electricity 

 and that of the battery on the development of plants ; the influence 

 of electric currents and electro-magnetic induction on the circulation 

 of the sap and the direction of the organs ; the permeability of dif- 

 ferent vegetable parts to the rays of heat emanating from the sun or 

 from artificial sources, as well as their electric conductibility ; the 

 polarizing and refractive properties of several tissues traversed by 

 lumiuous and calorific rays ; the electric currents which exist in the 

 soil and in the plants which vegetate in it, &c. 



The following are the conclusions to which the examination has 

 led me : — 



1 . The rheometer detects the existence of electric currents in all 

 parts of vegetables, except those which are furnished with isolating 

 substances, as certain scales and various fruits of the Conifer?e, or 

 which contain scarcely any internal humidity, such as old bark, sca- 

 rious hairs, &c. 



2. These currents exist night and day, in the sun as well as in 

 the shade ; they are not destroyed by aetherization continued for 

 twenty-four hours, nor by the partial or total separation of the por- 

 tion examined with the remainder of the plant, so long as that por- 

 tion is not dry. 



3. In the roots, the stems, the branches, the petioles and the pe- 

 duncles, there exists a central descending current and a peripherical 

 ascending current. I call them axial currents. 



4. On connecting by means of the galvanometer the layers of the 

 stem where the liber and the alburnum touch (and where several bo- 

 tanists admit a descending current of sap), either with the most cen- 

 tral parts (pith and perfect wood), or with the most external parts 

 (young bark), we find a lateral current passing from these layers to 

 the neighbouring organs. The current from the cambium to the 

 pith is a derivation from the axial currents. In some roots the 

 central body and the cortical substances are alike positive with rela- 

 tion to the succeeding layers, which they touch and unite. The 

 young bark is, like the cambium, negative relatively to the pith. 



5. In most leaves, the current proceeds from the lamina to the 

 nerves, as well as to the central parts of the petiole and the stalk. 

 In certain fleshy plants, it is directed from the medullary or cortical 

 portions of the stalk toward the rnesophyllum, and from the latter 



