AMERICAN HOME GAEDEN. 505 



always upon tliat wliich is most desirable and proper, but upon 

 "what can be had in their season of need. If, therefore, the 

 rains have carried off the elements of this and the two preced- 

 ing divisions from the barn-yard, and they have been previous- 

 ly largely cropped out of the soil and sold off without return 

 to the land, no grand and heavy crop can be expected. 



Under the general terras saline or inorganic elements are 

 included, in very various proportions, Silica or Flint, Lime, 

 Magnesia, Alumina, Potash, Soda, metallic Oxides, Phospho- 

 ric and Sulphuric Acids, Chlorine, and a few other constitu- 

 ents ; and, though their aggregates, as shown in this division, 

 are small as compared with those of Nos. 5 and 6, yet they 

 are, more or less of them, essential to every crop, and can not 

 be taken ))y the plant from the atmosphere, whence much of 

 the material for the others may probably be derived. Hence 

 this division becomes of special importance, showing as it does 

 the total amormt of the privation which land su.stains by the 

 loss of these elements in a given cro|). 



By far the greater portion of these aggregates, however, are 

 derived from about one half of the elements named above. Of 

 the 24 lbs. of inorganic matter given in the table as obtained 

 from the product of an acre of wheat, about 8-j lbs. may be Sil- 

 ica, 2 lbs. Lime, 2 lbs. Magiiesia, 4i lbs. Potash, and 5 lbs. 

 Soda ; and of the 240 lbs. yielded by the straw, about 189 lbs. 

 may be reckoned as Silica, 16 lbs. Lime, 2 lbs. Magnesia, IJ 

 Ibs. Potash, and 2 lbs. Soda, with some 10 lbs. Phosphoric 

 Acid ; the small remaining balance in both being composed 

 of minute portions of the other elements. The large predom- 

 inance of silica and lime is a remarkable featm'e in this di^d- 

 sion, and may illustrate the natm-al law by which supply and 

 demand are regulated in the vegetable and animal kingdoms. 

 Without the silica, neither com, grain, nor grass would stand 

 upright to maturity ; it forms the outer coating and strength- 

 ener of the stem of these and certain other plants, and may, 

 without impropriety, be said to furnish to them the bones of 

 vegetable growth. The lime is equally essential to the forma- 

 tion and strength of animal bones, of which it constitutes so 

 large a part. Extraordinary means are sometimes used to 



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