SNOW. 



as a tonic. It is found in rich woodlands, in the 

 Middle States. The root is perennial. 



SXOW. This well-known precipitation from 

 the atmosphere serves to defend winter grain- land) 

 crops and all other vegetables from the severity 

 of frosts; for, being a very bad conductor of 

 heat, it prevents the internal warmth of the 

 earth from being carried off* through the surface 

 of the land, and consequently ameliorates the 

 soil. The plants being thus sheltered, shoot 



SOIL. 



These, he calculates (Elements of Chemistry, p. 

 51), will contain and carry away from the soil 

 (supposing none of them to be eaten on the 



l:imh 



Ibs. 



Sulphuric acid 111 

 Phosphoric acid 90 

 Chlorine . . 39 



Potash . 

 Soda . 

 Lime 

 Magnesia 

 Silica 



Ibs. 

 280 

 150 

 242 

 50 

 318 



Total 1280 



cherished b} the genial 

 with increased 



e sun, vegetate 

 As ammonia and 



that, if we carry off the entire produce, and 

 the shape of manure, we 



dition, 



Pivirl or potash ... 390 Ibs. ata cost of 3 10 

 Crystallized carbonate of 



2 12 



3 13 2 



cherishes vegetation by the protection it affords, 

 but by ' the direct influence of the fertilizers 

 referred to. 



SODA. See KELP ; SALTS, their uses to vege- 

 tation, tVc. 



SOD BURNING. See PARING and BURNING. 



SOFT-GRASS. See HOLCUS. 



SOIL. The upper surface of the earth which 

 furnishes a medium or basis for the growth of 

 plants. Prof. Johnston, in his Elements of Che- 

 mistry, has remarked, that the earthy part of the ^ e ma y safely, then, adopt the conclusion of 

 soil is not, as some have supposed, a mere sub- j Liebig, when he tells us (Organic Chemistry, p. 

 stratum, in which the plant may so root itself as ' 63) that " many of these inorganic constituents 

 to be able to maintain its upright position against i va T according to the soil in which the plants 

 the force of winds and tempests, but it is a ?row, but a certain number of them are indis- 

 storehouse of food also, from which the roots of pensable to their developernent. All substances 

 the plant may select such earthy substances as i" solution in a soil are absorbed by the roots 

 are necessary or fitted to promote its growth. ' plants, exactly as a sponge imbibes a liquid, 

 And the young farmer, when he is endeavouring am l a " that it contains, without selection. The 

 to understand the true theory of the food of sub>tanc's thus conveyed to plants are retained 

 plants, and the operation of fertilizers, must dis- ' n greater or less quantity, or are entirely sepa- 

 curd from his mind all suspicion that these rated when not suited for assimilation. 



The results of these chemical researches it 

 will be found very serviceable to bear in mind, 

 in the investigation of the composition and uses 

 of all fertilizers. 



earthy and saline substances, found in the sub- 

 stance of his crops, are merely there by acci- 

 dent, or absorbed by their roots accidentally in 

 the moisture of the soil; for, on the contrary, it 

 has been shown that these substances are always The chief cultivated soils with whi< h the 

 found in the plant, and that they vary in amount : farmer has to encounter, although in reality mix- 

 at different stages of its growth. Thus, to give ' tures of sand, clay, and lime with various saline 

 a single instance, Mr. J. P. Norton (Tnms. High, land organic matters, may, for the convenience 

 Soc. 1SJ5, p. 321; Farmer's Almanack, vol. iii. j of something like a classification, be arranged 

 p. 19) has shown that the ashes of the stalk of j under the heads of sand, clay, and lime. These, 

 the unripe potato-oat contained I it must be remembered, are fertilizing according 



to the proportions in which they are blended to- 

 gether ; and, as a general rule, it may be taken 

 that, whenever any one of these earths is defi- 

 cient in a soil, the addition of such earth will 

 add to its fertility; and hence they all, in some 

 situation or other, are found to be useful addi- 

 tions or fertilizers to soils in which the added 

 earth naturally exists in insufficient piopor- 

 tions. 



In burning a piece of wood or any other vege- 

 table substance, a small portion of it remains 

 behind, called the ash or inorganic part which 

 is a compound substance consisting of various mi- 

 neral substances, gases, &c., that have served as 

 the food of the growing plant or tree, and which 

 it is the proper function of soils to supply. 

 Such are silica or flint; alumina, or the basis of 

 clay ; potash, soda, lime, magnesia, oxide of iron, 

 chlorine united with the soda in the form of com- 

 mon salt, sulphuric acid, phosphoric acid, car- 

 bonic acid. The portions of the wood or other 

 vegetable matter lost or dispersed in the burning 

 are termed the organic constituents. Sand, clay, 

 and lime, although they compose such a large 

 amount of the inorganic constituents of soils, 

 have associated with them many other substance! 



It is true that the amount of these fixed or in- 

 organic substances varies in the same species of 

 plant grown on different soils ; but, although 

 the proportions vary, the ingredients do not 

 alter; and so closely is the proportion preserved 

 in which they exist, that Professor Johnston has 

 been able to determine pretty accurately the 

 general amount of the inorganic ingredients car- 

 ried off the soil, per acre, by the ordinary rota- 

 tion of the four-course system. As the basis of 

 this calculation, he supposes the turnips to con- 

 sist of 25 tons of bulbs, and 7 tons of tops ; the 

 barley, of 38 bushels of 63 Ibs. each, and 1 ton 

 of straw; the clover and rye-grass, of 1 ton of 

 each in hay; and the wheat crop to be composed 

 of 25 bushels of 60 Ibs., and If tons of straw. 



4*2 



1001 



