times its weight of black flux; or, if this cannot be procured, with two parts of very dry carbonate of potassa (the salt of tartar of the shops), and one of powdered charcoal. Dr. Bostock finds that, for this mixture, we may advantageously substitute one composed of half a grain of charcoal, and two drops of oil, to a grain of the sediment. Procure a tube eight or nine inches long, and onefourth or one-sixth of an inch in diameter, of thin glass, sealed hermetically at one end. Then put into the tube the mixture of the powder and its flux, and, if any should adhere to the inner surface, let it be wiped off by a feather, so that the inside of all the upper part of the tube may be quite clean and dry. Stop the end of the tube loosely, with a little paper, and heat the sealed end only, on a chafing-dish of red-hot coals, taking care to avoid breathing the fumes. The arsenic, if present, will rise to the upper part of the tube, on the inner surface of which it will form a thin brilliant coating. Break the tube, and scrape off the reduced metal. Lay a little on a heated iron, when if it be arsenic, a dense smoke will arise, and a strong smell of garlic will be perceived. The arsenic may be farther identified, by putting a small quantity between two polished plates of copper, surrounding it by powdered charcoal, to prevent its escape, binding these tightly together by iron wire, and exposing them to a low red heat. If the included substance be arsenic, a white stain will be left on the copper. It may be proper to observe that neither the stain on copper, nor the odor of garlic, is produced by the white oxide of arsenic, when heated without the addition of some inflammable ingredient. The absence of arsenic must not, therefore, be inferred, if no smell should be occasioned by laying the white powder on heated iron. Dr. Black ascertained that all the necessary experiments, for the detection of arsenic, may be made on a single grain of the white oxide; this small quantity having produced, when heated in a tube with its proper flux, as much of the metal as clearly established its presence. If the quantity of arsenic in the stomach should be so small, which is not very probable, as to occasion death, and yet to remain suspended in the washings, the whole contents, and the water employed to wash them, must be filtered, and the clear liquor assayed for arsenic by the tests. In this case it is necessary to be careful that the color of the precipitate is not modified by that of the liquid found in the stomach. If this be yellow, the precipitate by sulphate of copper and carbonate of potassa will appear green, even though no arsenic be present; but on leaving it to settle, decanting off the fluid, and replacing it with water, it will evidently be blue without any tinge of green, being no longer seen through a yellow medium. The liquid contents of the stomach may also be evaporated to dryness below 250° Fahrenheit, and the dry mass be exposed to heat at the bottom of a Florence flask, to sublime the arsenic. If dissolved in an oily fluid, Dr. Ure proposes to boil the solution with distilled water and afterwards to separate the oil by the capillary action of wick threads. The watery fluid may then be subjected to the usual tests. M. Orfila has gone into ample details on the modifications produced by wine, coffee, tea, broth, &c., on arsenical tests, of which a good tabular abstract is given in Mr. Thomson's London Dispensatory. But it is evident that the differences in these menstrua, as also in beers, are so great as to render precipitations and changes of color by reagents very unsatisfactory witnesses, in a case of life and death. Hence the method of evaporation above described should never be neglected. Should the arsenic be combined with oil, the mixture ought to be boiled with water, and the oil then separated by the capillary action of wick-threads. If with resinous substances, these may be removed by oil of turpentine, not by alcohol (as directed by Dr. Black), which is a good solvent of arsenious acid. It may moreover be observed that both tea and coffee should be freed from their tannin by gelatin, which does not act on the arsenic, previous to the use of reagents for the poison. When one part of arsenious acid in watery solution is added to ten parts of milk, the sulphureted hydrogen, present in the latter, occasions the white color to pass into a canary yellow; the cupreous test gives it a slight green tint, and the nitrate of silver produces no visible change, though even more arsenic be added; but the hydrosulphurets throw down a golden yellow, with the aid of a few drops of an acid. The liquid contained in the stomach of a rabbit poisoned with a solution of three grains of arsenious acid afforded a white precipitate with nitrate of silver. grayish-white with lime-water, green with the ammoniaco-sulphate, and deep yellow with sulphureted hydrogen water. The preceding copious description of the habitudes of arsenious acid in different circumstances is equally applicable to the soluble arsenites. Their poisonous operation, as well as that of the arsenic acid, has been satisfactorily referred by Mr. Brodie to the suspension of the functions of the heart and brain, occasioned by the absorption of these substances into the circulation, and their consequent determination to the nervous system and the alimentary canal. This proposition was established by numerous experiments on rabbits and dogs. Wounds were inflicted, and, arsenic being applied to them, it was found that in a short time death supervened, with the same symptoms of inflammation of the stomach and bowels as if the poison had been swailowed. He divides the morbid affections into three classes: 1st, Those depending on the nervous system, as palsy at first of the posterior extremities, and then of the rest of the body, convulsions, dilatation of the pupils, and general insensibility: 2d, Those which indicate disturbance in the organs of circulation; for example, the feeble, slow, and intermitting pulse, weak contractions of the heart immediately after death, and the impossibility of prolonging them, as may be done in sudden deaths from other causes, by artificial respiration: 3d, Lastly, Those which depend on lesion of the alimentary canal, as the pains of the abdomen, nauseas, and vomitings, in those animals which were suffered to vomit At one time it is the nervous system that is most remarkably affected, and at another the organs of circulation. Hence inflammation of the stomach and intestines ought not to be considered as the immediate cause of death, in the greater number of cases of poisoning by arsenic. However, should an animal not sink under the first violence of the poison, if the inflammation has had time to be developed, there is no doubt that it may destroy life. Mr. Earle states that a woman who had taken arsenic resisted the alarming symptoms which at first appeared, but died on the fourth day. On opening her body the mucous membrane of the stomach and intestines was ulcerated to a great extent. Authentic cases of poison are recorded where no trace of inflammation was perceptible in the primæ viæ. The effects of arsenic have been graphically represented by Dr. Black :-The symptoms produced by a dangerous dose of arsenic begin to appear in a quarter of an hour, or not much longer, after it is taken. First sickness, and great distress at stomach, soon followed by thirst, and burning heat in the bowels. Then come on violent vomiting, and severe colic pains, and excessive and painful purging. This brings on faintings, with cold sweats, and other signs of great debility. To this succeed painful cramps, and contractions of the legs and thighs, and extreme weakness and death.' Similar results have followed the incautious sprinkling of schirrous ulcers with powdered arsenic, or the application of arsenical pastes. The following more minute specification of symptoms is given by Orfila:An austere taste in the mouth; frequent ptyalism; continual spitting; constriction of the pharynx and œsophagus; teeth set on edge; hiccups; nausea; vomiting of brown or bloody matter; anxiety; frequent fainting fits; burning heat at the præcordia; inflammation of the lips, tongue, palate, throat, stomach; acute pain of stomach, rendering the mildest drinks intolerable; black stools of an indescribable fœtor; pulse frequent, oppressed and irregular, sometimes slow and unequal; palpitation of the heart; syncope; unextinguishable thirst; burning sensation over the whole body, resembling a consuming fire; at times an icy coldness; difficult respiration; cold sweats; scanty urine, of a red or bloody appearance; altered expression of countenance; a livid circle round the eyelids; swelling and itching of the whole body, which becomes covered with livid spots, or with a miliary eruption; prostration of strength; loss of feeling, especially in the feet and hands; delirium; convulsions, sometimes accompanied with an insupportable priapism; loss of the hair; separation of the epidermis; horrible convulsions; and death.' It is uncommon to observe all these frightful symptoms combined in one individual; sometimes they are altogether wanting, as is shown by the following case, related by M. Chaussier: -A robust man of middle age swallowed arsenious acid in large fragments, and died without experiencing other symptoms than slight syncopes. On opening his stomach, it was found to contain the arsenious acid in the very same state in which he had swallowed it. There was no appearance whatever of erosion or inflammation in the intestinal canal. Etmuller mentions a young girl's being poisoned by arsenic, and whose stomach and bowels were sound to all appearance, though the arsenic was found in them. In general, however, inflammation does extend along the whole canal, from the mouth to the rectum. The stomach and duodenum present frequently gangrenous points, eschars, perforations of all their coats; the villous coat in particular, by this and all other corrosive poisons, is commonly detached, as if it were scraped off or reduced into a paste of a reddish-brown color. From these considerations we may conclude, that from the existence or non-existence of intestinal lesions, from the extent or seat of the symptoms alone, the physician should not venture to pronounce definitely on the fact of poisoning. The result of Mr. Brodie's experiments on brutes teaches that the inflammations of the intestines and stomach are more severe when the poison has been applied to an external wound, than when it has been thrown into the stomach itself. Corrosive sublimate (the bichloride or oxymuriate of mercury), next to arsenic, is the most virulent of the metallic poisons. It may be collected by treating the contents of the stomach in the manner already described; but as it is more soluble than arsenic, viz. in about nineteen times its weight of water, no more water must be employed than is barely sufficient, and the washings must be carefully preserved for examination. If a powder should be collected, by this operation, which proves, on examination, not to be arsenic, it may be known to be corrosive sublimate by the following characters :— Expose a small quantity of it, without any admixture, to heat in a coated glass tube, as directed in the treatment of arsenic. Corrosive sublimate will be ascertained by its rising to the top of the tube, lining the inner surface in the form of a shining white crust. Dissolve another portion in distilled water; and it may be proper to observe how much of the salt the water is capable of taking up. To the watery solution add a little lime-water. A precipitate of an orange-yellow color will instantly appear. To another portion of the solution add a single drop of a dilute solution of subcarbonate of potassa (salt of tartar). A white precipitate will appear; but, on a still further addition of alkali, an orange-colored sediment will be formed. The carbonate of soda has similar effects. Sulphureted water throws down a dark-colored sediment, which, when dried and strongly heated, is wholly volatilised without any odor of garlic. For the detection of corrosive sublimate, Sylvester has recommended the application of galvanism, which exhibits the mercury in a metallic state. A piece of zinc wire, or, if that cannot be had, of iron wire, about three inches long, is to be twice bent at right angles, so as to resemble the Greek letter II. The two legs of this figure should be distant about the diameter of a common gold wedding-ring from each other, and the two ends of the bent wire must afterwards be tied to a ring of this description. Let a plate of glass, not less than three inches square, be laid as nearly horizontal as possible, and on one side drop some sulphuric acid, diluted with about six times its weight of water, till it spreads to the size of a halfpenny. At a little distance from this, towards the other side, next drop some of the solution supposed to contain corrosive sublimate, till the edges of the two liquids join together; and let the wire and ring, prepared as above, be laid in such a way that the wire may touch the acid, while the gold ring is in contact with the suspected liquid. If the minutest quantity of corrosive sublimate be present, the ring in a few minutes will be covered with mercury on the part which touched the fluid. Smithson remarks that all the oxides and saline compounds of mercury, if laid in a drop of marine acid on gold, with a bit of tin, quickly amalgamate the gold. In this way a very minute quantity of corrosive sublimate, or a drop of its solution, may be tried, and no addition of muriatic acid is then required. Quantities of mercury may thus be rendered evident which could not be so by any other means. Even the mercury of cinnabar may be exhibited; but it must previously be boiled with a little sulphuric acid in a platinum spoon, to convert it into sulphate. An exceedingly minute quantity of metallic mercury in any powder may be discovered by placing it in nitric acid on gold, drying, and adding muriatic acid and tin. The only mineral poison of great virulence that has not been mentioned, and which, from its being little known to act as such, it is very improbable we should meet with, is the carbonate of baryta. This, in the country where it is found, is employed as a poison for rats, and there can be no doubt would be equally destructive to human life. It may be discovered by dissolving it in muriatic acid, and by the insolubility of the precipitate which this solution yields on adding sulphuric acid, or sulphate of soda. Soluble barytic salts, if these have been the means of poison, will be contained in the water employed to wash the contents of the stomach, and will be detected, on adding sulphuric acid, by a copious precipitate. It may be proper to observe that the failure of attempts to discover poisonous substances in the alimentary canal after death is by no means a sufficient proof that death has not been occasioned by poison. For it has been clearly established, by experiments made on animals, that a poison may be so completely evacuated that no traces of it shall be found, and yet that death may ensue from the morbid changes which it has occasioned in the alimentary canal, or in the general system. Copper and lead sometimes gain admission into articles of food, in consequence of the employment of kitchen utensils of these materials. 1. If copper be suspected in any liquor its presence will be ascertained by adding a solution of pure ammonia, which will strike a beautiful blue color. If the solution be very dilute it may be concentrated by evaporation; and, if the liquor contain a considerable excess of acid, like that used to preserve pickles, as much of the alkali must be added as is more than sufficient to saturate the acid. In this, and all other experiments of the same kind, the fluid should be viewed by reflected, and not by transmitted light. If into a newly prepared tincture of guaiacum wood we drop a concentrated solution of a salt of copper, the mixture instantly assumes a blue color. This effect does not take place when the solution is very weak, for example when there is not above half a grain of the salt to an ounce of water; but then, by the addition of a few drops of prussic acid, the blue color is instantly developed of great purity and intensity. This color is not permanent, but soon passes to a green, and at length totally disappears. For want of prussic acid, distilled laurel water may be employed. The test produces its effect, even when the proportion of the salt of copper to the water does not exceed 1-45000th. In this minute proportion no other test, whether the prussiate of potassa, soda, or ammonia, gives the least indication of copper. 2. Lead is occasionally found, in sufficient quantity to be injurious to health, in water that has passed through leaden pipes, or been kept in leaden vessels, and sometimes even in pump water, in consequence of that metal having been used in the construction of the pump. Acetate of lead has also been known to be fraudulently added to bad wizes, with the view of concealing their defects. Lead may be discovered by adding, to a portion of the suspected water, about half its bulk of water impregnated with sulphureted hydrogen gas. If lead be present it will be manifested by a dark brown, or blackish, tinge. This test is so delicate that water condensed by the leaden worm of a still tub is sensibly affected by it. Lead is also detected by a similar effect ensuing on the addition of sulphuret of ammonia, or potassa. For discovering the presence of lead in wine, a test invented by Dr. Hahnemann, and known by the title of Hahnemann's wine test, may be employed. This test is prepared by putting together, into a small phial, sixteen grains of sulphuret of lime, prepared in the dry way (by exposing to a red heat, in a covered crucible, equal weights of powdered lime and sulphur, accurately mixed), and twenty grains of bitartrate of potassa (cream of tartar). The phial is to be filled with water, well corked, and occasionally shaken for the space of ten minutes. When the powder has subsided decant the clear liquor, and preserve it in a well-stopped bottle for use. The liquor, when fresh prepared, discovers lead by a dark colored precipitate. A farther proof of the presence of lead in wines is the occurrence of a precipitate on adding a solution of the sulphate of soda. Sylvester has proposed the gallic acid as an excellent test of the presence of lead. The quantity of lead which has been detected, in sophisticated wine, may be estimated at forty grains of the metal in every fifty gallons. When a considerable quantity of acetate of lead has been taken into the stomach (as sometimes, owing to its sweet taste, happens to children,) after the exhibition of an active emetic, the hydrosulphuret of potassa or of ammonia may be given; or pro bably a solution of sulphate of soda (Glauber's salt) would render it innoxious. The following tests of arsenic and corrosive sublimate have been lately proposed by Brugnatelli-Take the starch of wheat boiled in water until it is of a proper consistence, and recently prepared; to this add a sufficient quantity of iodine to make it of a blue color; it is afterwards to be diluted with pure water until it becomes of a beautiful azure. If to this some drops of a watery solution of arsenic be added, the color changes to a reddish hue, and finally vanishes. The solution of corrosive sublimate, poured into iodine and starch, produces almost the same change as arsenic; but if, to the fluid acted on by the arsenic, we add some drops of sulphuric acid, the original blue color is restored with more than its original brilliancy, while it does not restore the color to the corrosive sublimate mix ture. POISONNIER (Peter Isaac), M. D., was born at Dijon in 1720, and in 1746 succeeded M. Dubois as professor of physic in the college de France. In 1758 he was first physician to the French army, and was called into Russia, to attend the empress Elizabeth. Here he assisted at the famous experiment relative to the congelation of quicksilver, of which he afterwards gave an account to the Academy of Sciences. He was made, on his return to France, counsellor of state and inspector-general of physic; and received a pension of 12,000 livres for his discovery of distilling fresh from sea-water. During the ascendancy of Robespierre he was imprisoned; but released on his death, and died in 1797 or 1798. He wrote several treatises on the maladies of seamen, the West India fever, &c. POITIERS, LIMONUM, a large and very ancient city, the principal place of the department of the Vienne, France, with a population of 21,000 inhabitants: having a royal court for the departments of the Vienne, the Lower Charente, the Two Sèvres and the Vendée, an inferior court of justice, a chamber of commerce and manufactures, an agricultural society, a university academy, a faculty of law, a royal college, a free drawing school, and medical, chemical, and pharmaceutical courses of lectures. This city stands in a picturesque situation, on the side of a steep hill, surrounded by lofty rocks, at the confluence of the Boivre and the Clain, which almost surround it. It is encircled with ancient walls, flanked with towers at intervals, and is in general badly built; the streets are narrow, close, and very steep, but the appearance of the place is pleasant. The public walk of PontGuillon, which occupies the interval between the two rivers; the old towers, the ruins, still imposing, of the gothic castle which once stood here the beautiful verdant carpet, through which the limpid streams wander, watering the majestic alleys of the boulevards; the whole view, in short, of the town, which rises in an amphitheatre, is one of the most delightful in France. Poitiers was a place of some note in the time of the Romans, who adorned it with an amphitheatre and an aqueduct. In 1356 king John lost under its walls the fatal battle, which cost him his liberty; and the English carried him into England, where they kept him prisoner. During the wars against the English, Charles VII. transferred the parliament of Paris hither for some time; in 1569 admiral Coligny laid siege to it; and since that time its ancient castle has been almost razed to the ground. In this city the unfortunate Urbain Grandier was tried, condemned, and burnt alive, accused of having bewitched the nuns of Loudun. It was in an age renowned for its intelligence and for the great men that have flourished in it; the very time, in fact, of the foundation of the French Academy, that this juridical assassination was perpetrated, and which was only equalled by the punishment of the young chevalier de la Barre 132 years after. Here are manufactories of coarse cloth, woollen counterpanes, caps, vinegar, starch, earthenware, playing cards, harnessing, carriages, &c.; also linen bleaching grounds, paper mills, dyehouses, tanyards, &c. The inhabitants carry on a trade in corn, wine, brandy, vinegar, wool, hemp, flax, honey, wax, skins, iron, &c. There is a departmental nursery here, and races from the 18th to the 20th of May, for thirty-two departments. Among the public institutions may be mentioned the library containing 12,000 volumes, the cabinet of natural history and philosophy, the botanic garden, the assembly room, the public walk, one of the finest and pleasantest in France, from which there is a delightful view, the baths, and the cathedral, built in the eleventh century, one of the finest specimens of gothic architecture. At a short distance from this city is an enormous stone raised above the ground supposed to be a monument of the Celtic times. The ancient province of Poitou presents many stones of this description, but this is the most remarkable; it is about twenty feet long, by seventeen broad, and three feet thick, supported by a single pillar. Poitiers is ninety miles south of Tours, eighty-seven north-west of Limoges, ninety-three north of Angoulême, 105 E. N. E. of Rochelle, and 265 south-west of Paris. POITOU, the name, before the revolution, of a province of France, bounded by Anjou on the north, Saintonge on the south, and the ocean on the west. It was divided into Upper and Lower Poitou, and was about 210 miles in length, by seventy in breadth. It is now divided into the departments of LA VIENNE, DEUX SEVRES, and LA VENDE E. See these departments. POIVRE (N.), a celebrated French botanist and traveller, born at Lyons in 1715. He studied in the Missionary Congregation at Paris, and then went to China, where he was imprisoned two years, after which he went to Cochin China. In 1745 he returned to France; and afterwards went to the East Indies; but the ship in which he sailed was taken on the passage by the British, and carried into Batavia; where he made many observations, before he returned to Paris. In 1749 he was appointed envoy from Louis XV. to the king of Cochin China, for the purpose of opening a commercial intercourse with that country. He resided several years in various parts of the East, and returned to Paris, My correspondent writes against master's gowns Spectator. and poke sleeves. Swed. poku, puk, a stake. To feel in the dark; to search any thing with a long instrument; the iron bar with which we stir the fire; an instrument anciently made use of to adjust the plaits of the ruffs which were then worn. Your ruff must stand in print, and for that purpose get poking-sticks with fair long handles, lest they scorch your hands. Middleton's Blurt Master Constable, a Comedy, 1602. Shakspeare. Winter's Tale. If these presumed eyes be clipped off, they will make use of the protrusions or horns, and poke out their way as before. Browne. If the poker be out of the way, stir the fire with Swift. the tongs. POL DE ST. LEON, a manufacturing town in the department of Finisterre, France, near the sea, and situated on an eminence. Its manufactures are leather and pottery; and it has a considerable trade in the linen and horses of the adjacent country. Population 5500. Twelve miles north-west of Morlain, and thirty-four north-east of Brest. POLA, an ancient city of Italy, in the south part of Istria, with a citadel and bishop's see. It is seated on a hill near a deep bay of the Adriatic, forty-four miles south of Trieste. It was originally founded by the Colchians, and afterwards made a Roman colony, and named Pietas Julia. (Plin. iii. 9; Mela, ii. 3; Strabo, i. & v.) It has still the remains of a Roman amphitheatre, and a triumphal arch. POLA, in ichthyology, a flat fish, resembling the soal, but somewhat shorter and smaller, It called also cynoglossus and linguatula. abounds in the Mediterranean, and is sold both in Rome and in Venice for the table. POLA, an ancient town, formerly a considerable city of Austrian Illyria, in the peninsula of Istria, on the gulf of Venice. It is still a bishop's see; but its population is dwindled down to a tenth of what it was in the time of the Romans, i.e. not above 1000. Its harbour, however, is large and excellent. POLACHIA, a ci-devant palatinate of Poland, now annexed to Prussia. It was bounded on the north by Prussia and Lithuania; on the east by Lithuania: south by Lublin, and west by Masovia. It is eighty-eight miles long, and thirty broad. POLACRE, a ship with three masts, usually navigated in the Levant and other parts of the Mediterranean. These vessels are generally furnished with square sails upon the main-mast, and lateen sails upon the fore and mizen masts. Some of them, however, carry square sails upon all the three masts, particularly those of the cidevant Provence in France. Each mast is commonly formed of one piece, so that they have neither top-mast nor top-gallant-mast; neither have they any horses to their yards, because the men stand upon the top-sail-yard to loose or furl the top-gallant-sail, and on the lower-yard to reef, loose, or furl, the top-sail, whose yard is lowered sufficiently down for that purpose. POLAN D. POLAND, an extensive country of Central Europe, part of the ancient Sarmatia, is bounded on the north and east by Russia; on the south by Hungary, Walachia, and Moldavia; on the west by Prussia and other German states. No other European territory has undergone such extensive changes of sovereignty. At the end of the fourteenth century, on the annexation of Lithuania, it contained an area of 284,000 square miles, or was nearly one-third larger than France. It was then divided into the provinces To Austria |