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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1852 Excerpt: ...or not at all so. On the other hand, their compounds with the alkalies and ammonia readily form double salts with the earths and metallic oxides (apocrcnic acid is penta-basic, crenic tetra-basic); the alkalies are therefore not only a means of rendering these acids readily soluble, but they assist in conveying the earths into plants by absorption. Alumina plays a special part in reference to crenic and apocrenic acids, since it forms perfectly insoluble compounds with them, in which the acids are preserved from decomposition, and cannot be washed away by water; yet they are not thereby completely withheld from plants, since these compounds are capable of decomposition by ammonia, which is thus a means of conveying these compounds into plants very gradually, by continuous decomposition. Most important as the above described relation of the humous acids to ammonia is, since their great affinity for it places them in a condition to attract this body, so important to vegetation, from the air and from the animal substances decomposing in the soil, and prepares them for absorption by the roots, yet they acquire still more importance from the fact that, according to Mulder's researches, the continuous decomposition of the humous substances is connected with formation of ammonia, since the oxygen of the air is used for the higher oxidation of the rest of their substance. The evidence that nitrogen is also conveyed to plants in this way, lies in an experiment of Mulder's (" Phys. Chemistry"), according to which, young Bean-plants which were raised in an atmosphere free from ammonia, in ulmic acid prepared from sugar free from ammonia, and in wood-coal, with water free from ammonia, yielded, on analysis, twice or thrice as much nitrogen as the seeds from w...