. Elements of agricultural chemistry and geology. Agricultural chemistry. 6 ORGANIC AND INORGANIC PARTS OF PLANTS, &C. that it is what physiologists term organised. If he examine, in like manner, a lump of earth or rock, he will perceive no such structure. To mark this distinction, the parts of animals and vegetables, either living or dead—whether entire or in a state of decay—are called organic bodies, while earthy and stony sub- stances are called inorganic bodies. Organic substances are more or less readily burned away and dissipated by heat in the open air ; inorganic substances are ge
. Elements of agricultural chemistry and geology. Agricultural chemistry. 6 ORGANIC AND INORGANIC PARTS OF PLANTS, &C. that it is what physiologists term organised. If he examine, in like manner, a lump of earth or rock, he will perceive no such structure. To mark this distinction, the parts of animals and vegetables, either living or dead—whether entire or in a state of decay—are called organic bodies, while earthy and stony sub- stances are called inorganic bodies. Organic substances are more or less readily burned away and dissipated by heat in the open air ; inorganic substances are generally fixed and permanent in the fire. Now the crops which grow upon the land, as well as the soil in which they are rooted, contain a portion of both of these classes of substances. In all fertile soils there exists from 3 to 10 per cent, of vegetable or other matter, of organic origin. If we heat a portion of such a soil to redness in the open air, as in the annexed, (fig. 1,) this organic matter will burn away, leaving the inorganic or mineral matter behind. By this burn- ing, most soils are changed in color, but, if previously dried, Pig. are not materially diminished in bulk. The inorganic matter forms by far their largest part. All vegetables, again, as they are collected for food, leave, when burned, a sensible quantity of inorganic ash ; but of them it forms only a small part. Wood leaves about a J per cent, grain 2 or 3 per cent, straw about 5 per cent ; and only in rare cases does the ash left amount to 15 or 20 per cent of the weight of a vegetable substance. Hence, when a handful of wheat, wheat straw, hay, &c., is burned in the air, a compara- tively small weight of matter only remains behind. Every one r. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Johnston, Jas. F. W. (James
Size: 2036px × 1228px
Photo credit: © Paul Fearn / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1850, booksubjectagricul, bookyear1853
