Rudimentary Treatise on the Drainage of Districts and Lands

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J.Weale, 1859 - Drainage - 160 pages

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Page 47 - To understand the nature of the process, it will be necessary to advert, in a general way, to a few long-known chemical properties of the familiar substance chalk ; for chalk at once forms the bulk of the chemical impurity that the process will separate from water, and is the material whence the ingredient for effecting the separation will be obtained. " In water, chalk is almost, or altogether insoluble ; but it may be rendered soluble, by either of two processes of a very opposite kind. When burned,...
Page 132 - ... having forced it down about four feet below the bottom of the trench, on pulling it out, to his astonishment, a great quantity of water burst up through the hole he had thus made, and ran down the drain.
Page 22 - ... down to the finest powder; and, on account of their " extreme irregularity of shape, they cannot lie so close to " one another as to prevent there being passages between " them, owing to which circumstance soil in the mass is " always more or less porous. If, however, we proceed to " examine one of the smallest particles of which soil is " made up, we shall find that even this is not always solid, " but is much more frequently porous, like soil in the mass. " A considerable proportion of this...
Page 24 - ... has quite enough of air from the canals. it can never be without moisture, as every particle of soil which touches it, is well supplied with this necessary ingredient. This, then, is the proper condition of...
Page 26 - Of course, all these injurious effects are at once overcome by thorough-draining, the result of which is, to establish a direct communication between the interstitial canals and the drains, by which means it follows, that no water can remain any length of time in these canals without, by its gravitation, finding its way into the drains.
Page 10 - ... a precipitation ensues. If the masses are under saturation, then less precipitation takes place, or none at all, according to the degree. Also the warmer the air, the greater is the quantity of vapour precipitated in like circumstances...
Page 27 - ... of the whole bulk of the soil itself; for example, 100 cubic inches of moist soil (that is, of soil in which the pores are filled with water, while the canals are filled with air), contain no less than 25 cubic inches of air. According to this calculation, in a field pulverized...
Page 22 - The most careful examination has proved that the process of germination consists essentially of various chemical changes, which require for their development the presence of air, moisture, and a certain degree of warmth. Now it is obviously unnecessary for our present purpose that we should have the least idea of the nature of these processes : all we require to do, is to ascertain the conditions under which they take place ; having detected these, we know at once what is required to make a seed...
Page 25 - Not only are the pores filled, but the interstitial canals are likewise full, and the consequence is that the whole process of the germination and growth of vegetables is materially interfered with. We shall here, therefore, briefly state the injurious effects of an excess of water, for the purpose of impressing more strongly on your minds the necessity of thorough draining, as the first and most essential step towards the improvement of your soil.
Page 84 - ... an acre. This increase in value has arisen, not only from the land being cleared from the injurious effects of the water upon it, but from the improved system of cultivation it has enabled the farmers to adopt. The fen-lands in Cambridgeshire and great part of the neighbouring counties are formed of a rich black earth, consisting of decomposed vegetable matter, generally from 6...

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