in Natural History, properly denotes small particles of siliceous stones. Sands are subject to be variously blended, both with different substances, as that of talks, &c.; and hence, as well as from their various colours, are subdivided into, 1. White sands, whether pure or mixed with other arenaceous or heterogeneous particles; of all which there are several kinds, differing no less in the fineness of their particles than in the different degrees of colour, from a bright and shining white, to a brownish, yellowish, greenish, &c. white. 2. The red and reddish sands, both pure and impure. 3. The yellow sands, whether pure or mixed, are also very numerous. 4. The brown sands, distinguished in the same manner. 5. The black sands, of which there are only two varieties, viz. a fine shining grayish black sand, and another of a fine shining reddish-black colour. 6. The green kind; of which there is only one known species, viz. a coarse variegated dusky green sand, common in Virginia.
Sand is of great use in the glass manufacture; a white kind of 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 sand to render unctuous or clayey earths fertile, and fit to support vegetables, by making them more open and loose.
SAND-BAGS, in the art of war. See SACKS OF EARTH.
Sand-EEL. See AMMODYTES, Ichthyology Index.
SAND-FLODS, a name given to the motion of sand so common in the deserts of Arabia. Mr Bruce gives the following accurate description of some that he saw in travelling through that long and dreary desert. "At one o'clock (says he) we alighted among some acacia trees at Waadi el Halhoub, having gone twenty-one miles. We were here at once surprised and terrified by a sight surely one of the most magnificent in the world. In that vast expanse of desert from west and to north-west of us, we saw a number of prodigious pillars of sand at different distances, at times moving with great celerity, at others stalking on with a majestic slowness: at intervals we thought they were coming in a few minutes to overwhelm us; and small quantities of sand did actually more than once reach us. Again they would retreat so as to be almost out of sight, their tops reaching to the very clouds. There the tops often separated from the bodies; and these, once disjointed, dispersed in the air, and did not appear more. Sometimes they were broken near the middle, as if struck with a large cannon shot. About noon they began to advance with considerable swiftness upon us, the wind being very strong." strong at north. Eleven of them ranged alongside of us about the distance of three miles. The greatest diameter of the largest appeared to me at that distance as if it would measure ten feet. They retired from us with a wind at south-east, leaving an impression upon my mind to which I can give no name, though surely one ingredient in it was fear, with a considerable deal of wonder and astonishment. It was in vain to think of flying, the swiftest horse or fastest sailing ship could be of no use to carry us out of this danger; and the full persuasion of this rivetted me as if to the spot where I stood, and let the camels gain on me so much in my state of lameness, that it was with some difficulty I could overtake them.
"The same appearance of moving pillars of sand presented themselves to us this day, in form and disposition like those we had seen at Wadi Haliboub, only they seemed to be more in number and less in size. They came several times in a direction close upon us, that is, I believe, within less than two miles. They began immediately after sunrise, like a thick wood, and almost darkened the sun: his rays shining through them for near an hour, gave them an appearance of pillars of fire. Our people now became desperate: the Greek shrieked out, and said it was the day of judgment. Ifmael pronounced it to be hell, and the Tucorories, that the world was on fire. I asked Idris, if ever he had before seen such a sight? He said he had often seen them as terrible, though never worse; but what he feared most was that extreme redness in the air, which was a sure prelude of the coming of the simoom." See SIMOON.
The flowing of sand, though far from being so tremendous and hurtful as in Arabia, is of very bad consequences in this country, as many valuable pieces of land have thus been entirely lost; of which we give the following instances from Mr Pennant, together with a probable means of preventing them in future. "I have more than once (says he), on the eastern coasts of Scotland, observed the calamitous state of several extensive tracts, formerly in a most flourishing condition, at present covered with sands, unstable as those of the deserts of Arabia. The parish of Furlie, in the county of Aberdeen, is now reduced to two farms, and above 500l. a year lost to the Errol family, as appears by the oath of the factor in 1769, made before the court of session, to ascertain the minister's salary. Not a vestige is to be seen of any buildings, unless a fragment of the church.
"The estate of Coubin, near Forres, is another melancholy instance. This tract was once worth 300l. a-year, at this time overwhelmed with sand. This strange inundation was still in motion in 1769, chiefly when a strong wind prevailed. Its motion is so rapid, that I have been assured, that an apple-tree has been so covered with it in one season, that only the very summit appeared. This distress was brought on about ninety years ago, and was occasioned by the cutting down some trees, and pulling up the bent or star which grew on the sand hills; which at last gave rise to the act of 15 George III. c. 33. to prohibit the destruction of this useful plant.
"I beg leave to suggest to the public a possible means of putting a stop to these destructive ravages. Providence hath kindly formed this plant to grow only in pure sand. Mankind was left to make, in after-times, an application of it suitable to their wants. The sandhills, on a portion of the Flintshire shores, in the parish of Llanasa, are covered with it naturally, and kept firm in their place. The Dutch perhaps owe the existence of part at least of their country to the sowing of it on the mobile solum, their sand-banks.
"My humane and amiable friend, the late Benjamin Stillington, Esq. recommended the sowing of this plant on the sandy wilds of Norfolk, that its matted roots might prevent the deluges of sand which that country experiences. It has been already remarked, that wherever this plant grows, the salutary effects are soon observed to follow. A single plant will fix the sand, and gather it into a hillock; these hillocks, by the increase of vegetation, are formed into larger, till by degrees a barrier is made often against the encroachments of the sea; and might as often prove preventive of the calamity in question. I cannot, therefore, but recommend the trial to the inhabitants of many parts of North Britain. The plant grows in most places near the sea, and is known to the Highlanders by the name of murah; to the English by that of bent-grass, mat-grass, or marram. Linnaeus calls it arundo arenaria. The Dutch call it helm. This plant hath stiff and sharp-pointed leaves, growing like a rush, a foot and a half long: the roots both creep and penetrate deeply into their sandy beds: the stalk bears an ear five or six inches long, not unlike rye; the seeds are small, brown, and roundish. By good fortune, as old Gerard observes, no cattle will eat or touch this vegetable, allotted for other purposes, subservient to the use of mankind."
SAND-Piper. See TRINGA, ORNITHOLOGY Index.