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places covered with the flowers, which have some resemblance to our wood anemone but they have short naked pedicles, each supporting one flower at top. Some of these flowers will have ten or twelve petals, so that they appear to have a double range of leaves, which has occasioned their being termed double flowers; but this is only accidental, the same roots in different years producing different flowers.

SANGUISORBA, in botany, a genus of the Tetrandria Monogynia class and order. Natural order of Miscellaneæ, Linnæus. Rosacea, Jussieu. Essential character: calyx two-leaved, inferior; corolla superior; germ between the calyx and corolla. There are three species,

with several varieties.

SANICULA, in botany, sanicle, a genus of the Pentandria Digynia class and order. Natural order of Umbellatæ, or Umbelliferæ. Essential character: umbels clustered; subcapitate; fruit rugged; flowers of the disk abortive. There are three species.

SANTALUM, in botany, a genus of the Tetrandria Monogynia class and order. Natural order of Onagræ, Jussieu. Essential character: calyx four-toothed; corolla four-petalled, with the petals growing on the calyx, besides four glands; berry inferior, one-seeded. There is only one species, viz. S. album, white and yellow sandal wood. This tree has the appearance of a myrtle, with stiff branchiate branches, jointed; in habit, leaves and inflorescence, resembling the privet. It is a native of many parts of India. In the Circar mountains, where it is wild, it is of little value, as it is generally of a small stature. On the Malabar coast it is very large, and the wood of the best kind. The difference of colour constitutes two kinds of sanders, both employed for the same purposes, and having equally a bitter taste, and an aromatic smell. With the powder of this wood a paste is prepared, with which the Chinese, Indians, Persians, Arabians, and Turks, anoint their bodies. It is likewise burnt in their houses, and yields a fragrant and wholesome smell.

The great

est quantity of this wood, to which a sharp and attenuating virtue is ascribed, remains in India. The red sanders, though in less estimation, and less generally used, is sent by preference into Europe. This is the produce of a different tree, which is common on the coast of Coromandel. Some travellers confound it with the VOL. XI.

wood of Caliatour, which is used in dyeing.

The S. album, or white sanders, is brought from the East Indies, in billets about the thickness of a man's leg, of a pale-whitish colour. It is that part of the yellow sanders wood which lies next the bark. Great part of it, as met with in the shops, has no smell or taste, nor any sensible quality that can recommend it to the notice of the physician.

The S. flavum, or yellow sanders, is the interior part of the wood of the same tree which furnishes the former, is of a pale-yellowish colour, of a pleasant smell, and a bitterish aromatic taste, accompanied with an agreeable kind of pungency. This elegant wood might undoubtedly be applied to valuable medical purposes, though at present very rarely used. Distilled with water, it yields a fragrant essential oil, which thickens in the cold into the consistence of a balsam. Digested tincture; which being committed to disin pure spirit, it imparts a rich yellow tillation, the spirit arises, without bringing over any thing considerable of the flavour of the sanders. The residuum contains the virtues of six times its weight of the wood.

SANTOLINA, in botany, lavender cotton, a genus of the Syngenesia Polygamia Equalis class and order. Natural order of Composite Discoideæ. Corymbiferæ Jussieu. Essential character: calyx imbricate, hemispherical; down none; receptacle chaffy. There are six species, S. chamaecyparisus, common lavender cotton, grows naturally in the southern parts of Europe, and is much cultivated in English gardens. All the species are ornamental plants, and may be propagated by planting slips and cuttings in the spring.

SAP. See PLANT.

The sap of trees, chemically considered, is a watery mucilaginous liquid, often strongly saccharine, so as to yield a large quantity of sugar, and to furnish a very strong fermented liquor.

SAP, or SAPP, in the art of war, is the digging deep under the earth of the glacis, in order to open a covered passage into the moat. It is only a deep trench, covered at top with boards, hurdles, earth, sand-bags, &c. and is usually begun five or six fathoms from the saliant angle of the glacis.

SAPPHIC, in poetry, a kind of verse much used by the Greeks and Latins, denominated from the inventress Sappho. The sapphic verse consists of five feet, C

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SAPINDUS, in botany, soap-berry tree, a genus of the Octandria Trigynia class and order. Natural order of Trihilate. Sapindi, Jussieu.

Essential character: calyx four-leaved; petals four; capsule fleshy, connate, ventricose. There are thirteen species; of which we shall notice the S. saponaria, with winged leaves, which grows naturally in the islands of the West Indies, where it rises with a woody stalk from 20 to 30 feet high, sending out many branches with winged leaves, composed of several pair of spear. shaped lobes. The flowers are produced in loose spikes at the end of the branchcs; they are small and white, so make no great appearance. These are succeeded by oval berries as large as middling cher. ries, sometimes single, at others, two, three, or four, are joined together; these have a saponaceous skin or cover, which incloses a very smooth roundish nut of the same form, of a shining black when ripe. The skin or pulp, which surrounds the nuts, is used in America to wash linen; but it is very apt to burn or destroy it if often used, being of a very acrid

nature.

SAPONARIA, in botany, soapwort, a genus of the Decandria Digynia class and order. Natural order of Caryophyllei. Caryophylleæ, Jussieu. Essential character: calyx one-leafed, naked; petals five, clawed; capsule oblong, one-celled. There are nine species. S officinalis, a British plant, has a creeping plant, so that in a short time it would fill a large space of ground. The stalks are above two feet high, and of a purplish colour. The foot-stalks of the flowers arise from the wings of the leaves opposite; they sustain four, five, or more purple flowers each, which have generally too small leaves placed under them. The stalk is almost terminated by a loose bunch of flowers growing in form of an umbel; they have each a large swelling cylindri

cal empalement, and five broad obtuse petals, which spread open, of a purple colour. These are succeeded by oval capsules, with one cell filled with small seeds. The decoction of this plant is used to clean and scour woollen clothes :

the poor people in some countries use it instead of soap for washing; from which use it had its name.

SAPPHIRE. See CORUNDUM, where we have given the analysis of the blue corundum, or sapphire. It is infusible without addition before the blow-pipe, but with borax it melts with effervescence. Sapphire, an oriental ruby, of which an analysis is also given in the article CoRUNDUM, are, next to the diamond, the most valuable of precious stones, and are used in the finest kind of jewelry. The oriental ruby differs from the sapphire in its colour: it is also softer and of less specific gravity. In its geognostic character, it differs also from the ruby, as it occurs sometimes imbedded in corundum, which is an inmate of primitive mountains, while sapphire appears to be a production of a later period. The violet coloured sapphire is the oriental amethyst: the yellow, the oriental chrysolite and topaz; and the green, the oriental emerald.

SARACA, in botany, a genus of the Diadelphia Hexandria class and order. Natural order of Lomentaceæ. Essential character: calyx none; corolla funnelform, four-cleft; filaments three on each side the throat; legume pedicelled. There is but one species, viz. S. indica, a native of the East Indies.

SARCOCOL, in chemistry, a gum resin, supposed to be the product of the penea sarcocolla. It is brought from Persia and Arabia, in the form of small grains: they have a sweet and bitterish taste, and are very soluble in water.

SARMENTACACEÆ, in botany, the name of the eleventh class in Linna us's Fragments of a Natural Method, consisting of plants that have climbing stems and branches, which, like the vine, attach themselves to the bodies in their neighbourhood, for the purpose of support.

SAROTHRA, in botany, a genus of the Pentandria Trigynia class and order. Natural order of Rotaceæ. Caryophylleæ, Jussieu. Essential character: calyx fiveparted; corolla five-petalled; capsule one-celled, three-valved, coloured. There is but one species, viz. S. gentianoides, an annual plant, and a native of Virginia and Pennsylvania, growing abundantly in the fields, and under the bushes, in a dry

sandy ground, near the capital of the lat ter province

SARRACENIA, in botany, side-saddle flower, so named in honour of Dr. Sarrrazin, professor of botany, a genus of the Polyandria Monogynia class and order. Natural order of Succulentæ. Essential character: calyx double, three-leaved, and five-leaved; corolla five-petalled; capsule five.celled, with the style having a clypeate stigma. There are four spe cies, all natives of North America.

SARSAPARILLA, in pharmacy, the root of the rough smilax of Peru, consisting of a great number of long strings hanging from one head: these long roots, the only parts made use of, are about the thickness of a goose-quill, or thicker, flexible, and composed of fibres running their whole length: they have a bitterish but not ungrateful taste, and no smell: and as to their medicinal virtues, they are sudorific and attenuant, and should be given in decoction, or by way of dietdrink.

SASH, a mark of distinction, which, in the British service, is generally made of crimson silk for the officers, and of crimson mixed with white cotton for the serjeants. It is worn round the waist in most regiments; in some few, particularly in the Highland corps, it is thrown across the shoulder. Sashes were originally in vented for the convenience and ease of wounded officers, &c. by means of which, in case any of them were so badly wounded as to render them incapable of remaining at their posts, they might be car ried off with the assistance of two men. They are now reduced to a very small size, and of course unfit for the original purpose Both the sash and gorget, indeed, must be considered as mere marks of distinction, to point out officers on duty. In some instances they are worn together; in others, the gorget is laid aside, and the sash only worn. The British cavalry tie the sash on the right, the infantry on the left side. The sashes for the imperial army are made of crimson and gold, for the Prussian army black silk and silver, the Hanoverians yellow silk, the Portuguese crimson silk with blue tassels. The French have their sashes made of three colours, viz. white, pink, and light-blue, to correspond with the national flag.

SASSAFRAS, in pharmacy, the wood of an American tree, of the laurel-kind, imported in large straight blocks: it is said to be warm, aperient, and corroborant; and frequently employed, with

good success, for purifying the blood, for which purpose an infusion, in the way of tea, is a very pleasant drink its oil is very fragrant, and possesses most of the virtues of the wood.

SATELLITES, in astronomy, are certain secondary planets, moving round the other planets, as the Moon does round the Earth. They are so called because they always attend them, and make the tour about the Sun together with them. The words moon and satellite are sometimes used indifferently: thus, we say, either Jupiter's moons, or Jupiter's satellites; but usually we distinguish, restraining the term moon to the Earth's attendant, and applying the term satellite to the little moons more recently discovered about Jupiter, Saturn, and the Herschel planet, by the assistance of the telescope, which is necessary to render them visible.

The satellites move round their primary planets, as their centres, by the same laws as those primary ones do round their centre the Sun; viz. in such manner, that, in the satellites of the same planet, the squares of the periodic times are proportional to the cubes of their distances from the primary planet.

SATELLITES of Jupiter, are four little moons, or secondary planets, performing their revolutions about Jupiter, as that planet does about the Sun.

Simon Marius, mathematician of the Elector of Brandenburgh, about the end of November 1609, observed three little stars moving round Jupiter's body, and proceeding along with him; and in January, 1610, he found a fourth. In January, 1610, Gallileo also observed the same in Italy, and in the same year, published his observations. These satellites were also observed in the same month of January, 1610, by Thomas Harriot, the author of a work upon algebra, and who made constant observations on these satellites," from that time till the 26th of February, 1612.

When Jupiter comes into a line between any of his satellites and the Sun, the satellite disappears, being then eclipsed, or involved in his shadow. When the satellite goes behind the body of Jupiter, with respect to an observer on the Earth, it is then said to be occulted, being hidden from our sight by his body, whether in his shadow or not. And when the satellite comes into a position between Jupiter and the Sun, it casts a shadow upon the face of that planet, which we see as an obscure round spot. And

lastly, when the satellite comes into a line between Jupiter and us, it is said to transit the disk of the planet, upon which it appears as a round black spot. The periods or revolutions of Jupiter's satellites are found out from their conjunctions with that planet, after the same manner as those of the primary planets are discovered from their opposition to the Sun. And their distances from the body of Jupiter are measured by a micrometer, and estimated in semi-diameters of that planet, and thence in miles. The periodical times and distances of these satellites, and the angles under which their orbits are seen from the Earth, at its mean distance, from Jupiter, are as below.

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The eclipses of the satellites, especially of those of Jupiter, are of very great use in astronomy. First, in determining pretty exactly the distance of Jupiter from the earth. A second advantage, still more considerable, which is drawn from these eclipses, is the proof which they give of the progressive motion of light. It is demonstrated by these eclipses, that light does not come to us in an instant, although its motion is extremely rapid. For if the motion of light were infinite, or came to us in an instant, it is evident that we should see the commencement of an eclipse of a satellite at the same moment, at whatever distance we might be from it; but, on the contrary, if light move progressively, then, it is as evident, that the further we are from a planet, the later we shall be in seeing the moment of its eclipse, because the light will take up a longer time in arriving at us; and so it is found in fact to happen, the eclipses of these satellites appearing always later and later than the true computed times, as the Earth removes further and further from the planet. When Jupiter and the Earth are at their nearest distance, being in conjunction both on the same side of the Sun, then the eclipses are seen to happen the soonest; and when the Sun is

directly between Jupiter and the Earth they are at their greatest distance asunder, the distance being more than before by the whole diameter of the Earth's annual orbit, or by double the Earth's distance from the Sun; then the eclipses are seen to happen the latest of any, and later than before by about a quarter of an hour. Hence, therefore, it follows, that light takes up a quarter of an hour in travelling across the orbit of the Earth, or nearly eight minutes in passing from the Sun to the Earth; which gives us about 12 millions of miles per minute, or 200,000 miles per second, for the velocity of light. A discovery that was first made by Mr. Roemer.

The third and greatest advantage derived from the eclipses of the satellites, is the knowledge of the longitudes of places on the Earth. Suppose two observers of an eclipse, the one, for example, at London, the other at the Canaries; it is certain that the eclipse will appear at the same moment to both observers; but as they are situated under different meridians, they count different hours, being perhaps 9 o'clock to the one, when it is only 8 to the other; by which observations of the true time of the eclipse, on commuuication, they find the difference of their longitudes to be one hour in time, which answers to 15 degrees of longitude.

Saturn has seven secondary planets revolving about him. One of them, which till lately was reckoned the fourth in order from Saturn, was discovered by Huygens, the 25th of March, 1655, by means of a telescope 12 feet long; and the first, second, third, and fifth, at different times, by Cassini, viz. the fifth in October, 1671, by a telescope of 17 feet; the third in December, 1672, by a telescope of Campani's, 35 feet long; and the first and second in March, 1684, by help of Campani's glasses, of 100 and 136 feet. Finally, the sixth and seventh satellites were discovered by Dr. Herschel, with his 40 feet reflecting telescope, viz. the sixth on the 19th of Agust, 1787, and the seventh on the 17th of September, 1788. These two he has called the sixth and seventh satellites, though they are nearer to the planet Saturn than any of the former five, that the names or numbers of these might not be mistaken or confounded, with regard to former observations of them.

Moreover, the great distance between the fourth and fifth satellite gave occasion to Huygens to suspect that there

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The four first describe ellipses like to those of the ring, and are in the same plane. Their inclination to the ecliptic is from 30 to 31 degrees. The fifth describes an orbit inclined from 17 to, 18 degrees with the orbit of Saturn; his plane lying between the ecliptic and those of the other satellites, &c. Dr. Herschel observes, that the fifth satellite turns once round its axis exactly in the time in which it revolves about the planet Saturn; in which respect it resembles our Moon, which does the same thing. And he makes the angle of its distance from Saturn, at his mean distance, 17' 2". Philosophical Transactions, 1792, p. 22. See a long account of observations of these satellites, with tables of their mean motions, by Dr. Herschel. Philosophical Transactions, 1790.

The Herschel has six satellites, or moons, that revolve about him, like those of Jupiter and Saturn. These satellites were discovered by Dr. Herschel, who gave an account of them in the Philosophical Transactions.

SATIN, a glossy kind of silk stuff, the warp of which is very fine, and stands out so as to cover the coarser woof. Some satins are quite plain, others wrought; some flowered with gold or silver, and others striped, &c. The Chinese satins are most valued, be

cause of their cleaning and bleaching easily, without losing any thing of their lustre; in other respects they are inferior to those of Europe.

SATINET, a slight thin kind of satin, commonly striped, and chiefly used by the ladies for summer night gowns.

As

SATURATION, in chemistry. there are certain limits to the propor tions in which bodies combine together, beyond which they cannot pass, these are called the points of saturation; and when two bodies, in uniting together, have reached this point, they are said to be saturated, or the one body is said to be saturated with the other; in other words, the change has taken place, and a new compound is formed. When, for instance, a salt is dissolved in water, as common salt, the water combines only with a certain proportion; and whatever quantity of salt is added beyond this proportion, it falls to the bottom undissolved. The reason of this is, that the particles of the salt are held together by their affinity for each other; that is, by the force of cohesion. Now, before any combination can be effected between the particles of the salt and the water, this force must be overcome. The force of affinity, therefore, between the water and the particles of salt, is greater than that between the particles of salt themselves, and thus they are separated and dissolve in the water; but this force of affinity between the water and the salt is limited; and when it has arrived at its utmost limit, the action between the two bodies ceases. The two forces which were opposed to each other; that is, the force of affinity between the water and the salt on the one hand, and the force of cohesion between the particles of the salt on the other, are balanced. The water in this case is said to be saturated with salt.

SATUREIA, in botany, savory, a genus of the Didynamia Gymnospermia class and order. Natural order of Verticillatæ. Labiatæ, Jussieu. Essential character: corolla with segments nearly equal; stamina distant. There are eight species, S. hortensis, or summer savory, is an annual plant, which grows naturally in the south of France and Italy, but is cultivated in this country both for the kitchen and medicinal use. The S. montana, or winter savory, a perennial plant, growing naturally in the south of France and Italy, but it is cultivated in gardens, both for culinary and medicinal purposes. Both kinds are propagated by seeds.

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