Elements of Agricultural Chemistry and Geology

Capa
C.M. Saxton, 1851 - 249 páginas

No interior do livro

Páginas seleccionadas

Outras edições - Ver tudo

Palavras e frases frequentes

Passagens conhecidas

Página 42 - But the latter process does not go on so rapidly as the former ; so that, on the whole, plants when growing gain a large portion of carbon from the air.
Página 48 - Ib. - - 371 - - 87£ of ulmic acid. 501b. - - 78* - - 122it 5011). 56 106 of vinegar. In the interior of the plant, therefore, it is obvious that, whichever of these substances be present in the sap, the elements are at hand out of which any of the others may be produced. In what way they really are produced, the one from the other, and by what circumstances these transformations are favoured, it would lead into too great detail to attempt here to explain. (For fuller and more precise explanations...
Página 178 - ... compared with those of vegetable matters and with each other, can be pretty nearly estimated. In reference to their relative quantities of nitrogen, therefore, they have been arranged in the following order, the number opposite to each representing the weight in Ibs. which is equivalent to or would produce the same sensible effect upon the soil as lOOlbs.
Página 34 - Pure nitric acid consists of nitrogen and oxygen only ; the union of these two gases, so harmless in the air, producing the burning and corrosive compound which this is known to be. " It never reaches the roots of plants in this free and corrosive state. It exists in many soils, and is naturally formed in compost heaps, and in most situations where vegetable matter is undergoing decay in contact with the air ; but it is always in a state of chemical combination in these cases. With potash, it forms...
Página 44 - When a seed is committed to the earth, if the warmth and moisture are favorable it begins to sprout. It pushes a shoot upwards, it thrusts a root downwards ; but until the leaf expands and the root has fairly entered the soil, the young plant derives no nourishment other than water, either from the earth or from the air. It lives on the starch and gluten contained in the seed.
Página 73 - If 100 grains of clay soil leave no more than 10 of clay, it is called a sandy soil : if from 10 to 40, a sandy loam ; if from 40 to 70, a loamy soil ; if from 70 to 85, a clay loam ; if from 85 to 95, a strong clay soil.
Página 81 - the general result of the comparison of the soils of various districts with the rocks on which they immediately rest, has been that in almost every country the soils have as close a resemblance to the rocks beneath them, as the loose earth derived from the crumbling of a rock before our eyes bears to the rock of which it lately formed a part." The conclusion, therefore, is irresistible, that soils, generally speaking, have been formed by the crumbling or decay of the solid rocks — that there was...
Página 36 - The air we breathe, and from which plants also derive a portion of their nourishment, consists of a mixture of oxygen and nitrogen gases, with a minute quantity of carbonic acid, and a variable proportion of watery vapour. Every hundred gallons of dry air contain about 21 gallons of oxygen and 79 of nitrogen. The carbonic acid amounts only to one gallon in...
Página 44 - is committed to the earth, if the warmth and moisture are favourable, it begins to sprout. It pushes a shoot upwards, it thrusts a root downwards ; but, until the leaf expands, and the root has fairly entered the soil, the young plant derives no nourishment other than water, either from the earth or from the air. It lives on the starch and gluten contained in the seed.
Página 43 - ... told upon the authority of Professor Johnson, that upon lands of average fertility from one-third to four-fifths of the entire amount of carbon contained in the crop is obtained from the air ; and to catch the small amount of carbonic acid the tree hangs out thousands of square feet of leaf surface, in perpetual motion through an ever-moving air, and thus by the conjoined labours of millions of pores the substance of whole forests of solid wood is slowly extracted from the fleeting winds.

Informação bibliográfica