440 Miscellaneous Intelligence, 



12. On the Nature of Earths which, without Cultivation or Ma- 

 nure^ are more or less favourable to the Nourishment and Growth of 

 Plants, — This subject has been investigated by M. Jaume St. Hi- 

 laire, whose memoir is reported upon by MM. Thenard and Syl- 

 vestre, nearly in the following words — " The author remarks that 

 most philosophers who have analyzed arable earths, devoted them- 

 selves exclusively to such as had been cultivated, and in which the 

 primitive constitution was of course more or less altered. He be- 

 lieves that the various kinds of earth in their first state have par- 

 ticular powers of nourishing such and such plants, and thinks that 

 the exact knowledge of these peculiarities would enable cultivators 

 to put those seeds in the ground which are most suited to it. To 

 this end the author has analyzed, under the inspection of Vauquehn, 

 two kinds of earth, which he had collected ; one from the wood of 

 Meudon, in the plain of La Patte d'Oie, where the spontaneous 

 vegetation is vigorous and varied, and the other from the plain des 

 Sablons, where no cultivation had been carried on, and where the 

 plants were so few as to be scarcely visible. From these analyses, 

 and from others, which the death of Vauquelin prevented him 

 from concluding, he draws the inference, — i. that all earths are 

 composed of silica, alumina, lime, magnesia, &c., in different propor- 

 tions, plus a vegeto-animal matter, which is more abundant as the 

 earth is more fitted for the nourishment of plants ; ii. that plants 

 placed in earths, of which the constituent parts have an analogy 

 with the particular nature of the plants, do not exhaust the soil ; 

 iii. that a series of observations on the different species, genera, 

 and families, which grow naturally and in great numbers, perpetu- 

 ating themselves on certain soils, with the analysis of these same 

 soils, would be of great utility in agriculture. The reporters think 

 that agriculture would draw, from such labours, general inductions, 

 rather than positive directions, but still think they would possess 

 great interest. — Revue Ency. xlv. p. 762. 



