SAND, in natural history, a genus of fossils, the characters of which are, that they are found in minute concretions ; forming together a kind of powder, the genuine particles of which are all of a tendency to one determinate shape, and appear regular, though more or less com plete concretions; not to be dissolved or disunited by water, or formed into a co herent mass by means of it, but retain ing their figure in it ; transparent, vitri fiable by extreme heat, and not dissolu ble in, nor effervescing with, acids. See SAND-STONE.
Sand is of great use in the glass manu facture ; the white writing sand being employed for making of the white glass, and a coarse greenish-looking sand for the green glass. In agriculture it seems to be the office of sands to make unctu ous earths fertile, and fit to support vege tables, &c. For earth alone, we find, is liable to coalesce, and gather into a hard coherent mass, as appears in. clay ; and being thus embodied, and as it were glued together, is no way disposed to nourish vegetables.
Common sand is a very good addition, by way of manure, to all sorts of clay lands ; it warms them, and makes them more open and loose. The best sand for the farmer's use is that which is washed by rains from roads or hills, or that which is taken from the beds of rivers; the common sand that is dug in pits, never answers nearly so well. However, if mix ed with dung, it is much better than laid on alone : and a very fine manure is made by covering the bottom of sheep-folds with several loads of sand every week, which are to be taken away and laid on cold stiff lands, impregnated as they are with the dung and the urine of the sheep.
Beside clay-land, there is another sort of ground very improvable by sand ; this is that sort of black boggy land on which bushes and sedge grow naturally, and which they cut into turf in some places. Six hundred loads of sand being laid upon an acre of this land, according to the Cheshire measure, which is near double the statute acre, meliorate it so much, that without ploughing it will yield good crops of oats or tares, though before it would have produced scarcely any thing. If this crop is taken off, the land will be well dunged, and if then laid down for it will yield a large crop of sweet Once sanding this land will improve it for a vast number of years, and it will yield two crops of hay in the year, if there be weather to make it in. Some land in
Cheshire has been, by this means, ren dered of twelve times its former value to the owner. The bogs of Ireland, when drained, have been rendered very fruitful land, by mixing sand in this manner among the earth of which they consist. Add to this, that in all these boggy lands, the burning them, or firing their own turf upon them, is also a great advantage. The common peat, or turf ashes, mixed with the sand for these purposes, add greatly to its virtue. Sea-sand, which is thrown up in creeks and other places, is by much the richest of all sand for ma nuring the earth ; partly its saltness, and partly the fat and unctuous filth that is mixed among it, give it this great virtue. In the western parts of England, that lie upon the sea-coast, they make very great advantages of it. The fragments of sea shells also, which are always in great abundance in this sand, add to its virtues; and it is always the more esteemed by the farmers, the more of these fragments there are among it.
The sea-sand used as manure in differ ent parts of the kingdom, is of three kinds : that about Plymouth, and on other of the southern coasts, is of a blue-grey colour, like ashes, which is probably ow ing to the shells of muscles, and other fish of that or the like colour, being bro ken and mixed among it in great quantity. Westward, near the Land's End, the sea. sand is very white, and about the isles of Scilly it is very glistening, with small par tides of talc ; on the coasts of the North Sea, the sand is yellowish, brown, or red dish, and contains so great a quantity of fragments of cockle-shells, that it seems to be chiefly composed of them. The sea sand is accounted best which is of a red dish colour, the next in value to this is the bluish, and the white is the worst of all. Sea-sand is best when taken up from un der the water, or from sand-banks which are covered by every tide. The small grained sand is most sudden in its opera tion, and is therefore best for the tenant, who is only to take three or four crops ; but the coarse or large grained sand is much better for the landlord, as the good it does lasts many years.