This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1894 edition. Excerpt: ... substances are present in combination with silica and alumina, the origin of the soil thence becomes manifest. It has arisen from the disintegrated primary rocks, all of which contain more or less potassa, soda, lime, magnesia, manganese and iron, besides phosphoric, sulphuric, chlorine, fluorine, silica and alumina. From such earthy material from primary rocks, which have been associated with sediments of gypsum and lime, in combination with water and the atmosphere under the influence of the warmth and light of the sun, the plants which nourish man and beast originate. Now, as all the enumerated earthy materials with the exception of silica and alumina enter into the crops that are taken away from field, it is clear that they must be replaced. If we desire normal and healthy crops, and that men and animals living on them should find in them all that is necessary for their bodily sustenance (phosphate and fluorate of lime and magnesia for the formation of the bones and teeth, potassa, iron and manganese for the muscles, chloride of sodium for the serum of the blood, sulphur for the albumen of the blood, hydro-carbons for the nerve-fat), it will not suffice to merely restore the potassa, phosphoric acid and nitrogen. Other things are imperatively demanded. With regard to this I shall adduce one instructive example: The proprietor of an extensive estate wrote to me that he formerly manured with ammonia, super-phosphate and Chili-nitre, and although there was a steady retrogression in the yields, yet he continued to earn something. Of late, however, when he had passed over to manuring with iron slag and Chili-nitre, with a steady retrogression, at last neither rye, nor barley, nor oats would prosper, only, strange to say, wheat...