As the precipitate of muriate of silver is very perceptible, the nitric solution of silver is used as a test of the presence of muriatic acid in waters; for a drop of this solution poured into such waters will cause a very evident cloudiness. The solution of silver is also used by assayers to purify the nitric acid from any admixture of muriatic acid. In this state they call it precipitated aquafortis. M. Chenevix found that a chlorate of silver may be formed by passing a current of chlorine through water in which oxide of silver is suspended; or by digesting phosphate of silver with hyperoxymuriate of alumina. It requires only two parts of hot water for its solution, and this affords, on cooling, small white, opaque, rhomboidal crystals. It is likewise somewhat soluble in alcohol. Half a grain, mixed with half as much sulphur, and struck or rubbed, detonates with a loud report and a vivid flash.

Compounds of silver with other acids are best formed by precipitation from its solution in nitric acid; either by the acid itself, or by its alkaline salts. Phosphate of silver is a dense white precipitate, insoluble in water, but soluble in an excess of its acid. By heat it fuses into a greenish opaque glass. Carbonate of silver is a white insoluble powder, which is blackened by light. The fluate and borate are equally soluble. Distilled vinegar readily dissolves the oxide of silver, and the solution affords long white needles, easily crystallised. See SALTS.

The precipitates of silver, which are formed by the addition of alkalis or earths, are all reducible by mere heat, without the addition of any combustible substance. A detonating powder has been sold lately at Paris as an object of amusement. It is enclosed between the folds of a card cut in two lengthwise, the powder being placed at one end, and the other being notched, that it may be distinguished. If it be taken by the notched end, and the other be held over the flare of a candle, it soon detonates, with a sharp sound, and violent flame. The card is torn, and changed brown; and the part in contact with the composition is covered with a slight metallic coating of a grayish-white color.

This compound, which M. Descotils calls detonating silver, to distinguish it from the fulminating silver of M. Berthollet, may be made by dissolving silver in pure nitric acid, and pouring into the solution, while it is going on, a sufficient quantity of rectified alcohol; or by adding alcohol to a nitric solution of silver with considerable excess of acid. In the first case, the nitric acid into which the silver is put must be heated gently, till the solution commences, that is, till the first bubbles begin to appear. It is then to be removed from the fire, and a sufficient quantity of alcohol to be added immediately, to prevent the evolution of any nitrous vapours. The mixture of the two liquors occasions an extrication of heat; the effervescence quickly recommences, without any nitrous gas being disengaged; and it gradually increases, emitting at the same time a strong smell of nitric ether. In a short time the liquor becomes turbid, and a very heavy, white, crystalline powder falls down, which must be separated when it

ceases to increase, and washed several times with small quantities of water.

If a very acid solution of silver previously made be employed, it must be heated gently, and the alcohol then added. The heat excited by the mixture, which is to be made gradually, soon occasions a considerable ebullition, and the powder immediately precipitates. It would be superfluous to remind the chemist that the mixture of alcohol with hot nitric acid is liable to occasion accidents, and that it is consequently prudent to operate on small quantities. This powder has the following properties:-It is white and crystalline; but the size and lustre of the crystals are variable. Light alters it a little. Heat, a blow, or long continued friction, causes it to inflame with a brisk detonation. Pressure alone, if it be not very powerful, has no effect on it. It likewise detonates by the electric spark. It is slightly soluble in water. It has a very strong metallic taste. Concentrated sulphuric acid occasions it to take fire, and is thrown by it to a considerable distance. Dilute sulphuric acid appears to decompose it slowly.

Process for separating silver from copper by Mr. Keir.-Put the pieces of plated metal into an earthen glazed pan; pour upon them some acid liquor, which may be in the proportion of eight or ten pounds of sulphuric acid to one pound of nitre; stir them about, that the surfaces may be frequently exposed to fresh liquor, and assist the action by a gentle heat from 100° to 200° of Fahrenheit's scale. When the liquor is nearly saturated, the silver is to be precipitated from it by common salt, which forms a muriate of silver, easily reducible by melting it in a crucible with a sufficient quantity of potash; and, lastly, by refining the melted silver, if necessary, with a little nitre thrown upon it. In this manner the silver will be obtained sufficiently pure, and the copper will remain unchanged. Otherwise, the silver may be precipitated in its metallic state, by adding to the solution of silver a few of the pieces of copper, and a sufficient quantity of water to enable the liquor to act upon the copper.

Mr. Andrew Thomson, of Banchory, has recommended the following method of purifying silver, which he observes is equally applicable to gold. The impure silver is to be flatted out to the thinness of a shilling, coiled up spirally, and put into a crucible, the bottom of which is covered with black oxide of manganese. More of this oxide is then to be added, till the silver is completely covered, and all the spaces between the coils filled. A cover is then to be luted on, with a small hole for the escape of the gas; and after it has been exposed to a heat sufficient to melt silver, for about a quarter of an hour, the whole of the alloy will be oxidised. The contents of this crucible are then to be poured into a larger, into which about three times as much powdered green glass has been previously put; a cover luted on as before, to prevent the access of any inflammable matter; and the crucible exposed to a heat sufficiently strong to melt the glass very fluid. On cooling and breaking the crucible, the silver will be found reduced at the bottom, and perfectly pure.

Sulphur combines very easily with silver, if thin plates, imbedded in it, be exposed to a heat sufficient to melt the sulphur. The sulphuret is of a deep violet color, approaching to black, with a degree of metallic lustre, opaque, brittle, and soft. It is more fusible than silver, and this in proportion to the quantity of sulphur combined with it. A strong heat expels part of the sulphur. Sulphureted hydrogen soon tarnishes the surface of polished silver, and forms on it a thin layer of sulphuret.

The alkaline sulphurets combine with it by heat, and form a compound soluble in water. Acids precipitate sulphuret of silver from this solution.

Phosphorus left in a nitric solution of silver becomes covered with the metal in a dentritic form. By boiling, this becomes first white, then a light black mass, and is ultimately converted into a light brown phosphuret. The best method of forming a phosphuret of silver is Pelletier's, which consists in mixing phosphoric acid and charcoal with the metal, and exposing the mix

ture to heat.

Most metallic substances precipitate silver in the metallic state from its solution. The assayers make use of copper to separate the silver from the nitric acid used in the process of parting.

The precipitation of silver by mercury is very slow, and produces a peculiar symmetrical arrangement, called the tree of Diana. In this, as in all precipitations, the peculiar form may be affected by a variety of concomitant circumstances; for which reason one process usually succeeds better than another. Make an amalgam, without heat, of four drachms of leaf silver with two drachms of mercury. Dissolve the amalgam in four ounces or a sufficient quantity of pure nitric acid of a moderate strength; dilute this solution in about a pound and a half of distilled water; agitate the mixture, and preserve it for use in a glass bottle with a ground stopper. When this preparation is to be used, the quantity of one ounce is put into a phial, and the size of a pea of amalgam of gold, or silver, as soft as butter, is to be added; after which the vessel must be left at rest. Soon afterwards, small filaments appear to issue out of the ball of amalgam, which quickly increase, and shoot out branches in the form of shrubs.

Silver unites with gold by fusion, and forms a pale alloy, as has been already mentioned in treating of that metal. With platina it forms a hard mixture, rather yellower than silver itself, and of difficult fusion. The two metals do not unite well. Silver melted with one-tenth part of crude platina, from which the ferruginous particles had been separated by a strong magnet, could not be rendered clear of scabrous parts, though it was repeatedly fused, poured out, and laminated between rollers. It was then fused, and suffered to cool in the crucible, but with no better success. After it had been formed, by rolling and hammering, into a spoon for blowpipe experiments, it was exposed to a low red heat, and became rough and blistered over its whole surface. The quantities were 100 grains of silver, and ten grains of platina. Nitre was. added during the fusions.

Silver very readily combines with mercury. A very sensible degree of heat is produced when silver leaf and mercury are kneaded together in the palm of the hand. With lead it forms a soft mass, less sonorous than pure silver. With copper it becomes harder and more sonorous, at the same time that it remains sufficiently ductile: this mixture is used in the British coinage. Twelve parts and one-third of silver, alloyed with one of copper, form the compound called standard silver. The mixture of silver and iron has been little examined. With tin it forms a compound, which, like that of gold with the same metal, has been said to be brittle, however small the proportion; though there is probably as little foundation for the assertion in the one case as in the other. With bismuth, arsenic, zinc, and antimony, it forms brittle compounds. It does not unite with nickel. The compound of silver and tungsten, in the proportion of two of the former to one of the latter, was extended under the hammer during a few strokes; but afterwards split in pieces. See IRON.

The uses of silver are well known: it is chiefly applied to the forming of various utensils for domestic use, and as the medium of exchange in money. Its disposition to assume a black color by tarnishing, and its softness, appear to be the chief objection to its use in the construction of graduated instruments for astronomical and other purposes, in which a good white metal would be a desirable acquisition. The nitrate of silver, besides its great use as a caustic, has been employed as a medicine, it is said with good success, in epileptic cases, in the dose of one-twentieth of a grain, gradually increased to one-eighth, three times a-day. Dr. Cappe gave it in a dose of one-fourth of a grain three times a-day, and afterwards four times, in what he supposed to be a case of angina pectoris, in a stout man of sixty, whom he cured. He took it for two or three months. Dr. Cappe imagines that it has the effect of increasing the nervous power, by which muscular action is excited.

The frequent employment in chemical researches of nitrate of silver as a re-agent for combined chlorine, occasions the production of a considerable quantity of the chloride (muriate) of silver, which is usually reconverted into metal by fusion with potash in a crucible. But, as much of the silver is lost in this way, it is better to expose the following mixture to the requisite

An easier method, however, is to put the metallic chloride into a pot of clean iron or zinc, to cover it with a small quantity of water, and to add a little sulphuric or muriatic acid. The reduction of the chloride of silver by the zinc or iron is an operation which it is curious to observe, especially with the chloride in mass (lunacornea). It begins first at the points of contact, and speedily extends, in the form of ramifications, over its whole surface, and into its interior. Hence, in less than an hour, considerable pieces of horn-silver are entirely reduced. If the mass

who proposed to murder Joseph; and this seems the more probable from Joseph's singling him out, binding him, and detaining him as a prisoner and hostage, till the rest should return with Benjamin: Gen. xlii. 24. He had six sons, one of whom, Ohad, seems to have died without issue.

SIMEON, or the SIMEONITES, the descendants of the above patriarch, one of the twelve tribes of Israel. When they came out of Egypt, they amounted to 59,300 men fit to bear arms, under Shelumiel, their chief; but they never made any distinguished figure, either during the republic or under the monarchy. They appear in general to have been as deeply guilty, in the criminal affair of Peor, as Zimri their prince; and the 25,000 cut off in that affair had been mostly of this tribe; for at the enumeration, immediately after, their number was decreased to 22,000. See Num. xxv. and xxvi. 14, 15. This their recent wickedness appears to have been the reason why Moses omitted them in the farewell blessing which he pronounced upon all the other tribes: Deut. xxxiii. It is said that the narrow limits of their inheritance compelled them to become scribes, and disperse themselves among the other tribes, according to the curse denounced upon their father by Jacob.

SIMEON, a respectable old man of Jerusalem, who waited for the fulfilment of the prophecies respecting the coming of the Messiah, whom he had a divine intimation that he should live to see, and who bore public testimony to our Saviour in the temple in his infancy: Luke ii. 2535. From his speech, or address of thanks to God, on that occasion, and particularly from his prophetic address to the mother of Jesus, he appears to have had much clearer views of the nature of the Messiah's kingdom than the most of his countrymen of that age. But these too, perhaps, he had by immediate revelation. Tradition says that Simeon was the sou of the famous Hillel, president of the Jewish Sanhedrim, and that he taught the celebrated Gamaliel. See HILLEL.

SIMEON OF DURHAM, an English historian, the contemporary of William of Malmesbury, who took great pains in collecting the monuments of the history of England, especially in the north, after they had been scattered by the Danes. From these he composed a history of the kings of England, from A. D. 616 to 1130; with some smaller historical pieces. Simeon both studied and taught the sciences, and particularly the mathematics, at Oxford; and became precentor of the church at Durham, where he died. His history was continued by John, prior of Hexham, to A. D. 1156.

SIMEON STILITES, or STYLITES, a native of Syria, an anchoret, the founder of a sect, and the inventor of a ridiculous discipline, practised by him and his followers, called Stilites, or Pillar Saints, in the fifth century. Simeon passed thirty-seven years of his useless life on the top of these pillars; the first of which was six cubits high; the second twelve; the third twenty-two; the fourth thirty-six; and the last forty cubits high.

SIMETHUS, or SYMITHUS, an ancient town

of Sicily, near a river so named; where Virgil says the gods Palici were born. See PALICI. Virg. Æn. ix. v. 584.

SIMI, or SYMI, an island in the Mediterranean, between Rhodes and the continent of Asia, six miles north of Rhodes. Long. 45° 19′ E. of Ferro, lat. 36° 36′ N.

Mr.

SIMIA, the monkey, a genus of quadrupeds, belonging to the class of mammalia, and order of primates, in the Linnæan system, but by Mr. Pennant arranged under the digitated quadrupeds. According to the Linnæan system, the characteristics of this genus are these: There are four close set fore-teeth in each jaw; single tusks on each side in both jaws, which are longer than the rest, and somewhat remote from them. The grinders are obtuse, and the feet are formed like hands. Mr. Pennant gives the following generic description of the simia: There are four cutting teeth in each jaw, and two canine. Each of the feet is formed like a hand, generally with flat nails, and, except in one instance, has four fingers and a thumb. There are eyebrows both above and below. They are a numerous race; but almost all confined to the torrid zone. Kerr enumerates sixty-five species, and twenty varieties. They fill the woods of Africa from Senegal to the Cape, and thence to Ethiopia. They are found in all parts of India and its islands; in Cochin-China, in the south of China, and in Japan; one species is met with in Arabia; and they swarm in the forests of South America, from the isthmus of Darien as far as Paraguay. They are lively, agile, full of frolic, chatter and grimace. From the structure of their members, they have many actions in common with the human kind. Most of them are fierce and untameable; some are of a milder nature, and will show a degree of attachment; but in general they are endowed with mischievous propensities; and are filthy, obscene, lascivious, and thieving. They inhabit the woods, and live on trees; feeding on fruits, leaves, and insects. In general they are gregarious, going in vast companies: but the different species never mix with each other, always keeping apart, and in different quarters. They leap with vast activity from tree to tree, even when loaded with their young, which cling to them. They are the prey of leopards and others of the feline race; and of serpents, which pursue them to the summits of the trees, and swallow them entire. They are not carnivorous, but for mischief's sake will rob the nests of birds of the eggs and young. In the countries where they most abound, the sagacity of the feathered tribe is marvellously shown in their contrivances to fix the nest beyond the reach of these invaders. The simia being more numerous in their species than any other animals, and differing greatly in their appearances, it seemed necessary to methodise and subdivide the genus. Accordingly Mr. Ray first distributed them into three classes. 1. Simiæ, apes, such as want tails. 2. Cercopitheci, monkeys, such as have tails. 3. Papiones, baboons, those with short tails; to distinguish them from the common monkeys, which have very long ones. The principal marks by which the species of this genus are distinguishable from each other are derived, 1st, from the tail, which is either

long, short, or altogether wanting; or is straight or prehensile; 2dly, from the buttocks, which are naked, and furnished with callosities, or are covered with hair; 3dly, from the nails, which are flat and rounded like those of man, or sharp-pointed like the claws of beasts in general; 4thly, from the presence or absence of a beard on the chin; and, 5thly, from the cheeks being provided with, or wanting, pouches in their under parts. For greater convenience, the species of this genus, which are very numerous, are arranged under five subordinate divisions, considered as distinct genera by some authors, and not without reason. Three of these subdivisions were adopted by Linnæus; but Dr. Gmelin, following Buffon, has added other two, taken from the third division of his great precursor. These are the simiæ, papiones, cercopitheci, sapaji, and sagoines, which we proceed to describe in their alphabetical order:

I. S. apes have no tails. The visage is flat; The teeth, hands, fingers, feet, toes, and nails, resemble those of man, and they walk naturally erect. This division includes the simiæ, or apes properly so called, which are not found in Ame

rica.

II. S. cercopitheci, monkeys, have long tails, which are not prehensile; the under parts of their cheeks are furnished with pouches, in which they can keep their victuals; the partition between the nostrils is thin, and the apertures are, like those of man, placed in the under part of the nose; the buttocks are naked and provided with callosities. These animals, which are never found native in America, are the cercopitheci and Kußo of the ancients.

1. S. cercopithecus æthiops, the mangabey, or white-eyed monkey, has a long, black, naked, and dog-like face; the upper eye-lids of a pure white; ears black, and like the human: no canine teeth; hairs on the sides of the face, beneath the cheeks, longer than the rest; tail long; color of the whole body tawny and black; flat nails on the thumbs and fore fingers; blunt claws on the others; hands and feet black. shown in London some years ago, of place uncertain; that described by M. de Buffon came from Madagascar, was very good-natured, and went on all fours.

One was

2. S. cercopithecus aygula, the egret, has a long face, and an upright sharp-pointed tuft of hair on the top of the head. The hair on the forehead is black: the tuft and the upper part of the body light-gray; the belly white: the eye-brows are large; the beard very small. They are the size of a small cat; inhabit Java; fawn on men, on their own species, and embrace each other. They play with dogs, if they have none of their own species with them. If they see a monkey of another kind, they greet him with a thousand grimaces. When a number of them sleep, they put their heads together. They make a continual noise during the night.

3. S. cercop. cephus, the moustache, has a beard on the cheeks; the crown of the head is yellowish the feet are black, and the tip of the tail is of an ash color. Its tail is much longer than the body and head, being nineteen or twenty inches in length. The female menstruates.

4. S. cercop. cynocephalus, the dog-headed monkey, has no beard, and is of a yellow color; the muzzle is long; the tail long and straight, and the buttocks naked. It is a native of Africa. 5. S. cercop. cynomologus, the macaque of Buffon, or hare-lipped monkey of Pennant, has no beard; the nostrils are thick and divided; the tail is long and arched, and the buttocks are naked. He has cheek pouches, and callosities on the buttocks. His tail is from eighteen to twenty inches long. His head is large, his muzzle very thick, and his face naked, livid, and wrinkled. His ears are covered with hair. His body is short and squat, and his limbs thick and short. The hair on the superior parts of his body is of a greenish-ash color, and of a yellowish-gray on the breast and belly. He has a small crest of hair on the top of the head. He walks on four and sometimes on two feet. The length of his body, comprehending that of the head, is about eighteen or twenty inches. They are mild and tractable, but dirty.

6. S. cercop. cynosuros, the dog-tailed monkey, has a long tail and no beard; the face is long, with a sooty-colored forehead, and a whitish band over the eyes; the male parts are highly colored; the nails are convex. about the size of a middling dog; two feet high when erect. The species are deceitful, restless, and libidinous.-Kerr.

It is

7. S. cercop. diana, the spotted monkey, has a long white beard: the color of the upper parts of the body reddish, as if they had been singed, marked with white specks; the belly and chin whitish; tail very long; is a species of a middle size. It inhabits Guinea and Congo, according to Marcgrave; the Congese call it exquima. M. de Buffon denies it to be of that country; but from the circumstance of the curl in its tail, in Marcgrave's figure, and the description of some voyagers, he supposes it to be a native of South America. Linnæus describes his S. diana somewhat differently: he says it is of the size of a large cat; black spotted with white : hind part of the back ferruginous; face black; from the top of the nose is a white line passing over each eye to the ears, in an arched form; beard pointed, black above, white beneath, placed on a fattish excrescence; breast and throat white; from the rump, cross the thighs, a white line; tail long, straight, and black; ears and feet of the same color; canine teeth, large.

8. S. cercop. faunus, the marlbrouck, has a long tail, and is bearded: the tail is bushy at the extremity. It is a native of Bengal. This species has cheek-pouches, and callosities on the buttocks; the tail is nearly as long as the body and head; and it is a mistake of Clusius that it terminates in a tuft; the face is of a cinereous gray color, with a large muzzle, and large eyes, which have flesh-colored eye-lids, and a gray band cross the forehead instead of eye-brows; the ears are large, thin, and flesh-colored; the upper parts of the body are of a uniform yellowish brown color, and the lower of a yellowish gray: it walks on all fours, and is about a foot and a half from the muzzle to the extremity of the tail. The females menstruate.

9. S. cercop. fulvus, the tawny monkey, has