on Gardening and Rural Affairs. S 1 



temperature they require for the flowing or rise of the sap, is known to vary 

 materially in different plants; and M. Dutrochet, with great apparent 

 reason, thinks this is attributable to their different physical capacities for 

 producing electrical currents. 



The substance of M. Dutrochet's theory may thus be summed up : — The 

 sap of plants does not circulate ; it ascends from the root in the wood or 

 comparatively woody parts of stems and branches, and, being elaborated 

 into nutritive juice, descends by the vessels of the bark. The sap in ascend- 

 ing, and the juice in descending, are diffused laterally by horizontal vessels, 

 which meet in common in the space between the bark and the wood. The 

 sap and proper juice are poured out in this space, and these unite and form 

 increments both of bark and wood. All the motions of the sap and juice 

 in plants take place in consequence of the operations of two distinct cur- 

 rents of electricity : the one negative, by which the vessels have the power 

 of absorption, which M. Dutrochet calls endosmose, and by which the ves- 

 sels become turgid ; and the other positive, by which the vessels exude or 

 secrete, which power M. Dutrochet calls exosmose. 



It is gratifying to find that none of the results of M. Dutrochet's experi- 

 ments are materially at variance with the opinions of Mr. Knight : in some 

 minor points their hypotheses differ ; but all the important doctrines of 

 Mr. Knight are confirmed, and established by M. Dutrochet on a basis 

 which will not be easily moved. 



Du Petit-Thouars, Le Chevalier Aubert-Aubert, For. Mem. L. S. and H. S., 

 Membre de l'Academie royale des Sciences, &c. &c : Notice Historique 

 sur la Pepiniere du Roi au Roule. Paris. Pamph. 8vo. 2 Ivs. 

 From the time of Louis XIII., the kings of France have had nursery 

 gardens in the neighbourhood of Paris, outside the suburbs St. Honore, 

 now the suburb du Roule. Claude Mollet, who was principal gardener 

 there under Henry IV. Louis XIII. and XIV., says that, in 1620, he grafted 

 more than 20,000 trees in these nurseries. That which is the subject of 

 the present notice was, in 1772, destined by Louis XV. for the propagation 

 of exotic trees ; was put under the care of the Abbe Nolin, and ultimately 

 under M. Du Petit-Thouars. It is now proposed to turn this nursery into 

 a market-place, and the main object of the notice is to oppose this change, 

 which will fall the more heavily on M. Du Petit-Thouars, as he receives 

 3600 francs a year as its director. 



Palaiseau, J. L. G. B., Painter : Description d'un Jardin imaginaire, et 

 quelques Considerations sur les Avantages que peut offrir le Sejour de la 

 Campagne ; accompagnees de plusieurs Plans et E'levations applicables a 

 l'Execution des differentes Parties de ce Projet, et de quelques Ob- 

 servations sur PUtilite que l'Architecte pourrait retirer d'une Connais- 

 sance parfaite de la Perspective. Paris. 8vo, 4 pi. sfr. 

 Worth looking at by architects and landscape-gardeners. 



Poinsot : L'Ami des Jardiniers, ou Instruction Methodique a la porte~e des 

 Amateurs et des Jardiniers de Profession, sur tout ce que concerne les 

 Jardins Fruitiers et Potagers, Pares, Jardins Anglais, Parterres, Orange- 

 ries, et Serres chaudes. Avec 20 Gravures en Taille-douce. Paris. 1 804. 

 2 vols. 8vo. 



Du Bois, M. Louis, Member of several Academies,, and one of the Authors 

 of the Cours complet d' Agriculture, &c. : Pratique simplified du Jardin- 

 age, a l'Usage des Personnes qui cultivent ellesmeme un petit Domaine, 

 contenant un Potager, une Pepiniere, un Verger, des Espaliers, des 

 Serres, des Orangeries, et un Parterre. Paris. 1821. 12mo. 



Vol. III. —No. 9. g 



