Review of ChaptaVs Chemistry of Agriculture. 27 



and, like some magician of old, command the rich treasures 

 of the earth to come forth at their bidding. 



Speaking of the nature of soils, our author remarks: 



" In order that a plant should flourish in a soil, it is not always suffi- 

 cient that the earths composing it are of the right kind, or suitably pro- 

 portioned ; it is necessary to unite other circumstances which are not 

 always to be met with ; for exam[)le, the arable soils which are based 

 upon rocks, vary considerably in depth ; and the thickness of the bed 

 not only exerts an influence upon the powers of vegetation, but deter- 

 mines the kind of plant which can be cultivated upon it. The bed of 

 earth ought to be from ten to twelve inches in depth for grain, and much 

 more than that for clover, and sainfoin ; for trees, it must be much deep- 

 er than for these, otherwise their roots, running but little below the sur- 

 face of the ground, will extend their shoots to a great distance, and thus 

 exhaust the strength of a large portion of soil. Trees are often found 

 upon the sides of mountains, which are almost entirely devoid of a cov- 

 ering of earth, but in this case the chinks and crevices of the rocks sup- 

 ply the place of earth, or rather the rocks are of so spongy and porous a 

 nature, as to permit the roots to penetrate them. In the Cevennes and 

 Limousin, the most beautiful chestnuts are planted upon granite and 

 free-stone ; and the famous vines of the Hermitage prosper in a soil of 

 granite decomposed at the surface." 



Might not this be a useful hint in covering the barren sides 

 of many of our New England hills, by planting among the 

 debris which are broken from the tops .'' for we know that 

 considerable excellent soil rests among the loose fragments, 

 and moisture is longer retained than elsewhere. The grape 

 flourishes in volcanic countries, among the loose and decom- 

 posing lava, with a luxuriance seldom equalled, and many of 

 our native plants, as the Rubi, are found in great luxuriance 

 in such places. 



Again, on the subject of manures, are many important 

 facts : 



" The nutritive manures are those which contain juices or other sub- 

 stances, which, being dissolved in water, or otherwise divided to the 

 most minute degree, are capable of being drawn into the organs ofplants. 

 All the vegetable and animal juices are of this description." 



" The most useful art, perhaps, in agriculture, and that which requires 

 the most care, is the preparation of dungheaps. It requires the applica- 

 tion of certain chemical principles, which it is not necessary for me to 

 explain, since it is sufficient to point out to the agriculturist the rules 

 by which he should be governed in his proceedings, without requiring of 

 him an extensive knowledge of the theory upon which they are founded. 



" Solid substances, whether animal, vegetable, or mineral, do not en- 

 ter into plants unless they are previously dissolved in water, or are drawn 

 in with that fluid in a state of extreme division. 



" Animal and vegetable substances which are, by their nature, insolu- 

 ble in water, may, by being decomposed, form new soluble compounds, 

 capable of furnishing nourishment for plants. 



" Animal and vegetable substances deprived by the action of water of 

 their soluble particles, may, in the course of their decomposition, form 

 new compounds susceptible of being dissolved." 



" The clippings and parings of horns form an excellent manure, of 

 which the effisct is prolonged during a succession of years, owing to the 



