Sand (grain)

“ The sand-clay road surface consists of a natural or artificial mixture of sand and clay, in which the amount of clay is somewhat greater than sufficient to fill the voids in the dry sand. It may be assumed that the sand contains 40 per cent of voids and that at least 45 per cent of clay is required to fill the voids and bind the sand grains together, because the clay spreads the sand grains apart during the mixing, thus having the effect of increasing the voids. ”

“ True happiness will be theirs when mind, heart, and hand shall work in concert in the sight of Heaven, and there shall be a sacred harmony between God's goodness and the joys of his creatures. Then, instead of the pitiable and frightful figure of Death stalking, whip in hand, across the fields, the painter of allegories may place beside the peasant a radiant angel, sowing the blessed grain broadcast in the smoking furrow. ”

“ The sand-grains which enter into its composition are of a brown color throughout, while the pebbles are only colored externally. Compounds of iron are associated with the mass, and the waters of the district are also largely ferruginous, whence it is suggested that the formation may be due to a kind of cementing action exerted by the iron, left by the waters that have percolated through the sands.
Were the Ancient Italians Cannibals?—A somewhat remarkable discovery of human and animal remains is announced by Prof. ”

“ 'Grass no longer grows where my horse has trod.' Look here, before you and around you! There is not a grain of sand that has not been bathed in blood, and what is that grain of sand itself, if not the dust of death? But how rich this blood is, and how fertile is the dust! ”

“ The feeding tips of roots secrete acids that eat away lime and other substances that occur in rocks. Dead leaves and other discarded portions of the trees rot about their roots, and form soil of increasing depth. The largest trees grow on the rocky soil deposited at the base of the slope. The tree's roots prevent the river from carrying it off.
When granite crumbles, its different mineral elements are separated. Clear, glassy particles of quartz we call sand. Dark particles of feldspar become clay, and may harden into slate. Sand may become sandstone. ”

“ Throughout this section of country the surface is occasionally characterized by water-worn pebbles, and gravel of granite, gneiss, and quartz, but the predominant characteristic is sand, which in many instances prevails almost to the entire exclusion of vegetable mould. Large tracts are often to be met with, exhibiting scarcely a trace of vegetation. The whole region, as before hinted, is almost entirely destitute of a timber-growth of any description. In some few instances, however, sandy knobs and ridges make their appearance, thickly covered with red cedars of a dwarfish growth. ”

“ Only coarse sandy soil remains light and open without organic matter. Few soils are formed only of coarse sand, most are mixtures of sand, silt and clay. Sands are sharp-sided, relatively large rock particles similar to table salt or refined white sugar. Irregular edges keep sand particles separated, and allow the free movement of air and moisture. ”

“ I do it because I have found from long experience in growing plants that sand not only facilitates good drainage, but enables air to get to the roots of [50] the plants as it never can do when the soil is not light and porous. And sand is a sweetener of soil, as is charcoal. Of course not all plants are alike in their requirements. Roses, for instance, like a rather heavy, compact soil. In growing them use the loam without sand. If I had to choose between sand and manure in making potting-soil for nearly all plants adapted to window culture, I would take the sand. ”

“ In the Old World and in the humid region generally, sandstone and sandy soils are usually spoken of as being poor, because there the sand almost always consists of quartz grains only, and hence the fine portions alone can be looked to for plant nutrition. ”

“ In fact, the name given to each really expresses only the preponderating ingredient, and many sandstones contain much clay, shales and clay slates abound in lime, and limestones in sand or clay, so that it may sometimes be a matter of some difficulty to decide to which class they belong. Such mixtures usually produce better soils than either of their constituents separately, and accordingly, in those geological formations in which they occur, the soils are generally of excellent quality. ”

“ The grains of sand, however, will still remain of an appreciable average size, and where both sand and clay are being transported to the sea in one and the same stream, the clay will be transported to long distances, whilst the sand, being heavier, bulk for bulk, and also consisting of grains larger in size than grains of clay, will be rapidly deposited, and form beds of sand. Of course, if the current be a violent one, the sand is transported, not by being held in suspension, but rather by being pushed along the bed of the river ”

“ On ledges where the rock is exposed to view its surface is more or less discolored and the grains are loose and may be rubbed off with the finger. On gentle slopes the rock is covered with a soil composed of sand, which evidently is crumbled sandstone, and dark carbonaceous matter derived from the decay of vegetation. Clearly it is by the dissolving of the cement that the rock thus breaks down to loose sand. ”

“ So far as general examination has yet gone, and in order to offer some leading hints to the scientific inquirer, it may be observed, that sandy soils, such as are frequent in England, are seldom seen except in maritime situations; but there are many inland beds of a red substance, too soft to be called stone, yet too compact to be called sand, though perfectly reducible to that state by the action of the sun or artificial heat. ”

“ The flint gravels that cover much of the upland in the New Forest may also be borne in mind, as presenting the worst features of highly siliceous lands.
In a semi-arid climate, or one with only seasonal rains, the processes by which sandstone begets sandstone tend to develop desert wastes. The soils produced by weathering do not cake together, and are carried away by wind during the drier months. The bare rock appears over broad surfaces, just as it does in storm-swept limestone areas, and any hollow where shelter is afforded tends to become filled with sand (see Fig. 5) . ”

“ While the physical character is of secondary importance, as generous crops are grown in sandy soil as well as in heavy loams, still the ideal soil is a sandy loam, i. e., a mixture of organic matter, clay and sand. A subsoil of gravel, or the presence of hard-pan, is not desirable, as cultivation to a depth of from twelve to fifteen inches is necessary to produce the best results. ”

“ A great part of the surface of the globe is covered by sand. In fertile regions the soil is very often of a sandy nature; though most soils are mixtures of sand with clay or stones, and may be described as loams rather than as sands. Pure sandy soils are found principally near sea-coasts where the sand has been blown inwards from the shore, or on formations of soft and friable sandstone like the Greensand. ”

“ We may remark that almost all land proper for cultivation is reddish, and more or less mixed with these different matters; the particles of sand or stone found there are of two kinds, the one coarse and heavy, the other fine and sometimes impalpable. The largest comes from the lower strata loosened in cultivating the earth, or rather the upper mould, by penetrating into the lower, which is of sand and other divided matters, and forms those earths we call fat and fertile. The finer sort proceeds from the air, and falls with dew and rain, and mixes intimately with the soil. ”

“ Fig. 47. Highly cultivated sand in Kent. Gooseberries are growing in the foreground, vegetables behind, and hops in background
A sandy soil is in so many ways the opposite of a clay soil that we shall expect to find corresponding differences in the look of the country. A sandy soil does not hold water: it may get water up from the subsoil to supply the plant (see p. 66) , or, if it happens to lie in a basin of clay, it may even be very wet: otherwise it is likely to be too dry for ordinary plants. ”

“ Roughly speaking, soils may be divided into heavy and light—those that hold wet and those that do not. The heavy kinds are mostly clay, though pure peat retains a great deal of moisture. The light soils are gravel, limestone, and sand. If you are used to a heavy clay soil, you will envy the people who have a light sandy one; and then some day when you come to work a hungry, sandy garden, you will wish for some of the sticky soil that is not easy to handle, but which many plants love. ”

“ If the soil is loose, drying quickly after rain, and if it can be scattered about by the hand like sand on the sea shore, we know we are on a sandy soil and can look for pits where builder's sand is dug. But it may very likely happen that the soil is something in between, and that neither sand pits nor {2} clay pits can be found; if we ask what sort of soil this is we are told it is a loam. A gravel soil will be known at once by its gravel pits, and a chalk soil by the white chalk quarries and old lime kilns, while a peat soil is black, sometimes marshy and nearly always spongey to tread on. ”

“ In the phim thickets near the river the vegetation often becomes so dense that it is almost impossible to penetrate to the river's edge. The soil in these places is very rich and moist, so that many species of the shade plants of moist rich woodlands find in such thickets very favorable conditions. On the open areas of the river flats buffalo grass and grama grass constitute the best forage known in the Sand Hills. These low, sod-forming grasses are especially valuable as winter forage. ”

“ But in truth these tender shades show where the sand is weathered, for if we walk upon it and break the thin crust created by the last rain, the dream tints depart, and a brighter corn colour breaks through. Coarse mat-grass binds the dunes and helps to hold them together against the forces of wind and water; but their tendency is [24] to decrease. Perhaps observation would prove that their masses shift and vanish more quickly than we guess, for the sand is the sea's toy, and she makes and unmakes her castles at will. ”

“ Thus it is an exception to the general rule to meet with a limestone as pure as ordinary white chalk, or with clay as aluminous as that used in Cornwall for porcelain, or with sand so entirely composed of siliceous grains as the white sand of Alum Bay, in the Isle of Wight, employed in the manufacture of glass, or sandstone so pure as the grit of Fontainebleau, used for pavement in France. More commonly we find sand and clay, or clay and marl, intermixed in the same mass. When the sand and clay are each in considerable quantity, the mixture is called loam. ”

“ The effect of different rocks upon the preservation and diminution of the moisture of fertile soil, influences vegetation in various degrees. The retentive power of the surface of rocks is of the greatest importance, where the soil consists chiefly of sand, through which the water percolates, and passes off entirely, unless it meets with a stratum of such a nature, as to obstruct its passage, or comes upon a surface of solid rock. The cause of the sterility of sandy plains is not merely their sandy nature, but also the great depth of the mass or rock capable of retaining the water. ”

“ The upper sand forms a very productive arable soil, and the clay impervious, wet [Pg 94] and cold lands chiefly in pasture. The lower sand is generally unproductive.
It is an important agricultural remark, that where the clay (plastic clay) comes in contact with the top of the chalk, an improved soil is produced, and that where the chalk and the green sand mix, extremely fertile patches of country present themselves. (See pages 86 and 87.)
4. The Wealden formation, nearly 1000 feet thick, consists of 400 feet of sand, covered by 300 of clay, and resting upon 250 of marls and limestones. ”

“ This represents one of the great divisions of soil—sandy soil. The sea shores are great masses of pure sand. If soil were nothing but broken rock masses then indeed it would be very poor and unproductive. But the early forms of animal and vegetable life decaying became a part of the rock mass and a better soil resulted. So the soils we speak of as sandy soils have mixed with the sand other matter, sometimes clay, sometimes vegetable matter or humus, and often animal waste. ”

“ The warmest exposure is good for early vegetables, and the cooler and more shady for the main crop. Much can be done to regulate this by fences and buildings. They will be warm and early on one side, and cool and late on the other.
Soil.—A rich loam is always best. To convert stiff clay, or light sand and gravel, into a good loam, is an easy matter on so small a plat as is usually devoted to a garden. Draw an abundance of sand on clay-ground, plow deep and mix well, and one winter's frost will so pulverize the whole that it will be in excellent condition. ”

“ The clay and humus soils carry crops through dry weather better because of their power to hold moisture and to absorb or soak up moisture from below. It is for this reason also that clay and peaty soils more often need draining than sandy soils.
When rain falls on a sandy soil it enters readily, but it is apt to pass rapidly down and be, to a great extent, lost in the subsoil, for the sand has not sufficient power to hold much of it. ”

“ In any case the soil must be well prepared by deep digging, breaking the lumps, and laying up in ridges to be disintegrated by the weather, and if needful its texture should be amended, as far as possible, at the same time. A coat of clay may be spread over a piece of sand, to be thoroughly incorporated with it; on the other hand, where the staple is clay, the addition of sand will be advantageous. ”