from Italy, which was certainly an advantage to the manufacture. China silk being of a quality peculiarly adapted to several purposes, particularly in the gauze branch, which, at one time consumed a large proportion of it, though it has since become inconsiderable. By the act just mentioned, the East India Company were enabled to increase with advantage their import of silk, which at that time was not very considerable, raw silk being still principally brought from Turkey. Total quantity of raw silk imported into Great Britain in the year 1750. In 1763, an act was passed for rendering more effectual the act of 19 Henry VII. by imposing fines on the importers or venders of the articles therein prohibited, in addition to the forfeiture of the goods. This measure, though it might in some degree check the introduction of foreign articles, was by no means adequate to the object it had in view, as the importation still continued, which, from the jealousy and discontent it excited among the workmen in this manufacture, appeared likely, in the beginning of the year 1765, to be attended with serious consequences. The journeymen weavers and others connected with the trade, who conceived themselves injured by the common use of French silks, assembled in Spitalfields and Moorfields by beat of drum, in order to petition Parliament for redress by a total prohibition of such articles, and from thence proceeded in different bodies to St. James's and Westminster Hall. This disposition, and the report that the weavers in the inland towns were coming to London to join their distressed brethren, excited considerable alarm; they were, however, prevented from committing any great outrage, and finally appeased, by a seasonable subscription for their relief, and an association among the principal mercers to recall all the orders they had given for foreign manufactures. An act was also passed, prohibiting the importation of foreign manufactured silk stockings and gloves into Great Britain and the British dominions, and for rendering more effectual the act passed in 1763 for prohibiting other articles. For the encouragement of the throwing part of this manufacture, an act was likewise passed in 1765, for reducing the duties then payable on the importation of raw silk, for allowing a drawback on the exportation of raw and thrown silk to Ireland, and for prohibiting the exportation of raw silk from Ireland. In the next year an act was passed to prohibit the importation of foreign manufactured silks and velvets, and for preventing unlawful combinations of workmen employed in the silk manufacture; the preamble to the act stated, that great quantities of foreign wrought silks and velvets were daily brought into and sold in Great Britain. By another act a heavy additional duty was imposed on Italian silk crapes and tiffanies, imported into this country. Towards the end of the year 1767, it was determined, that all future court mournings should be shortened to one half of the time which had been usually observed. This was considered particularly beneficial to the silk manufacture, and the Weavers' Company presented an address to his Majesty on the occasion, in which they assured him that his benevolent resolution would "greatly promote the silk manufactures of this kingdom, give great spirit to the trade, tend to the improvement of it in many branches, and be the means of giving constant employment to the workmen, many of whom, owing to the late mournings, have been out of employ, and in want of bread." They also expressed their obligations to the Queen and the rest of the royal family, for their patronage and encouragement of the silk manufacture. An address was likewise presented on the same occasion, signed by all the principal merchants, manufacturers and others connected with the silk trade. The journeymen weavers, probably, supposing that, by their combination and riotous proceedings a few years before, they had obtained the exclusion of foreign silks, now adopted the same mode for obtaining an advance in the prices paid for workmanship, which being resisted by their employers, the men proceeded to the most disgraceful acts of violence and atrocity, associating together under the name of cutters, and going about in parties at night, disguised and armed with pistols, cutlasses, and other weapons; breaking into the houses of those workmen who did not join them, but followed their employ as usual, and cutting to pieces and destroying all the silk they found in the looms of such workmen. The value of the silks thus destroyed was very considerable; and, in some instances, they ill-treated or murdered those whom they found at work. Several were brought to justice; but it was a considerable time before this law. less disposition entirely subsided. In a dispute between masters and workmen, respecting pay, the opposite interests of the parties must always render it difficult to come to an amicable adjustment, and, after various attempts in this instance, an act was passed in 1773, to authorize the magistrates of the cities of London and Westminster, the county of Middlesex, and the liberty of the Tower, to settle the pay of the workmen in the different branches of this manufacture, in their respective districts. On the extension of the war in 1779. much inconvenience was experienced from the want of a sufficient supply of Italian thrown silk, caused in a great measure by an act of 2 William and Mary, by which the importation of Italian thrown silk was prohibited, unless imported according to the Navigation Act, and directly by sea, from some of the ports of the country of its growth or production: this regulation was therefore now suspended, and organzine silk, of the growth or production of Italy, was permitted to be imported from any port or place, or in any ships or vessels whatsoever. In consequence of this permis. sion, the silks of Italy were brought to England by a circuitous route over land, and imported from Ostend and other ports of Flanders, till the peace. At a period of the war, when the falling-off of the silk trade was very considerable, Mr. John Callaway, of Canterbury, fortunately introduced a new article, which afforded employment to many hands. It was called Canterbury muslin, by which name it is still known, and many elegant varieties having been produced: it gives employment to many hundred persons in London and elsewhere. As the prohibition of the importation of foreign manufactured silks did not extend to Italian crapes and tiffanies, which were permitted to be imported under a heavy duty, it was thought proper, in 1791, in consequence of improvements in the manufacture of these articles, to restrict this permission, by prohibiting the importation of silk crapes and tiffanies, of the manufacture of Italy, unless brought directly from thence, and by disVOL. XI. continuing the allowance of drawback on exportation. The continual frauds committed by the different classes of persons employed in this manufacture, by purloining part of the silk entrusted to them, and resorting weight of the remainder, which frequentto various expedients for increasing the ly rendered the part stolen but a small part of their employer's loss; and the difficulty of convicting the persons who encouraged these practices by purchasing the stolen silk, caused an act to be passed in 1792, by which, persons buying or receiving, in any manner, silk, from those employed to work it up, knowing them to be so employed, and not having the consent of the employer, are liable to punishment by fine, imprisonment, or whipping, although no proof should be given upon the trial, to whom the silk actually belonged. In the year 1793, this manufacture was affected more, perhaps, than any other, by the general commercial distress which then prevailed. The merchants, and particularly the East India Company, had large quantities of silk in their warehouses and the manufacturers were overstocked with goods, which brought the trade into a state of almost complete stag. nation, by which most of the workmen engaged in it were thrown out of employ, and experienced great distress. A public subscription was opened for their relief, and very liberally supported, from which the unemployed workmen and their families were supplied with bread; and when, from the approach of winter, their necessities increased, their relief was extended to other essential articles. By the report of the committee who superintended the distribution, it appeared that there were given away 795 chaldrons of coals, 583 pair of blankets, and in bread 121,741 quartern loaves. It was considered as a moderate computation, that 5,000 persons were totally unemployed, and that 5,000 more were only about half employed. In the course of the succeeding three or four years, the manufacture recovered its usual activity, and in the year 1798 was in a more flourishing situation than it had been in for several years previous. In the following year, the revival of velvets, as an article of female dress, proved very favourable to the workmen, as it rendered the employment of a greater number of hands necessary; and in 1800, few persons in this line were out of employ,. although the trade was somewhat checked by a considerable advance in the prices of raw and thrown silks. U The annual quantity imported on an average of the above years, is 1,251,629 pounds, from which deducting 79,206 pounds, the average quantity of raw and thrown silk imported during the above period, it leaves 1,172,423 pounds for the quantity consumed in the manufacture.Hence it appears, that the total annual value of this manufacture must be about 3,500,0001. of which but a small proportion is destined for exportation, the total annual value exported being about 700,0001.; more than half of which goes to America. During the year 1808, the exportation to America was suspended, and at the same time the interruption of commercial intercourse with the continent of Europe stopped, for a considerable time, the usual supply of silk from Italy; from which circumstances, the manufacture was brought into a very unprecedented situation, silk being sold in London at prices far greater than had ever been given before, while many of the masters were obliged to discharge the principal part of their workmen, from the demand for silk goods having, for a time, almost entirely ceased. These temporary embarrassments all manufacturers are liable to, particularly such as, like this, depend on other countries for their materials. SILK, in chemistry, in its natural state, contains a kind of yellow resinous matter, which gives its fine golden colour. When raw silk is infused in water, a portion of gummy matter is dissolved, and a light amber-coloured liquor is produced. Alcohol extracts a much deeper yellow, and makes a tincture that loses none of its colour by long exposure to the sun-beams, which bleaches the silk itself. Nitrous acid acts powerfully on silk; but, when concentrated nitric acid is distilled off silk, and the remaining liquor duly evaporated, much oxalic acid is obtained; and the residue, if evaporated, still further yields, with the remaining oxalic acid, a quantity of yellow, granular crystals, extremely bitter, not acid, and staining the saliva and hands of a deep yellow, Thrown Silk. 396,210 384,764 449,182 . 433,272 955.939 1,188,563 1,481,563 1,617,822 not easily removed. If the liquor is previously saturated with potash, and evaporated, another yellow silky salt separates, which detonates on coals like common nitre, and appears to be a triple combination of the former bitter substance with nitrate of potash. SILPHA, in natural history, the carrion beetle. Antennæ clavate; the club perfoliate; shells margined; head prominent; thorax somewhat flattened, margined. There are about 140 species, divided into sections. A. Lip dilated, bifid; jaw-onetoothed. B. Lip rounded, entire; jaw one-toothed. C. Lip horny, entire; jaw bifid. D. Lip emarginate, conic; jaw bifid. E. Lip heart-shaped, emarginate, crenate. F. Lip square, emarginate. G. Lip long, entire; antennæ serrate. H. Lip and jaw unknown. The insects of this genus are usually found among decaying animal and vegetable substances; frequenting dunghills, carrion, &c. and deposit their eggs chiefly in the latter. The larvæ are of a lengthened shape, roughened with minute spines and protuberances. S. vespillo is the most remarkable among European species: this is not uncommon in our own country. The animal is about threequarters of an inch long, and is distinguished by having the wing-sheaths considerably shorter than the abdomen. It seeks some decaying animal substance, in which it may deposit its eggs, and for the greater security contrives to bury it under ground. Sometimes three or four insects, working in concert, have been known to drag under the surface the body of a mole in the space of an hour, so that no trace of it has appeared above ground: the eggs are white and oval: from these are hatched the larvæ, which, when full grown, are more than an inch long. Each larvæ forms for itself an oval cell in the ground, in which it changes to a yellowish chrysalis, resembling that of a beetle, out of which, in somewhat less than three weeks, proceeds the perfect insect. This species diffuses a strong and unpleasant smell; it flies with considerable strength and rapidity, and is ge nerally seen on the wing during the hottest part of the day. SILPHIUM, in botany a genus of the Syngenesia Polygamia Necessaria class and order. Natural order of Composite Oppositifolia. Corymbiferæ, Jussieu.Essential character: calyx squarrose; seed down, margined, two-horned; receptacle chaffy. There are eight species. SILVER, which is divided by mineralogists into three species, the native, antimonial, and the arsenical, has been reckoned among the noble or perfect metals, and has been known from the earliest ages of the world. Its scarcity, beauty, and utility, have always rendered it an object of research among mankind, so that the nature and properties of this metal have been long studied and minutely investigated. In the midst of the rage for the transmutation of metals, which for centuries fired the imaginations of the alchymists, silver occupied a great share of their attention and labour, with the hope of discovering the means of converting the baser and more abundant metals into this, which is more highly valued on account of its scarcity and durability. When the dawn of science commenced, and its light had dissipated the follies and extravagances of these pursuits, the earliest chemists were much employed in examining the properties and combinations of silver; nor has it been overlooked or ne glected by the moderns. Silver, which is neither in such abundance nor so universally diffused as many other metals, exists in nature in five different states; in the native state; in that of alloy with other metals, especially with antimony; in that of sulphuret, sulphurated oxide, muriate, and carbonate. 1. Native silver, which is characterized by its ductility and specific gravity, is frequently tarnished on the surface, ofa rey or blackish colour, and appears under a great variety of forms. In this state it is not perfectly pure. It is usually alloyed with a little gold or copper. 2. The alloy of silver and antimony, which is the most frequent, is distinguished by its brittleness and lamellated structure from native silver, which it resembles in lustre and colour It crystallizes in prisms, which are six-sided, and pretty regular. 3. The sulphuret of silver, which is known to mineralogists by the name of vitreous silver ore, is of a dark grey colour, and has some metallic lustre. It is usually crystallized in the form of cubes, octahedrons with angular facets, or sometimes in the form of the dodecahedron. 4. The sulphurated oxide of silver and antimony. In this ore of silver the sul phur is combined with the metal in this state of oxide; in the former, in the metallic state. This ore is called red silver ore. It is of a deep red colour, sometimes transparent, and sometimes nearly opaque, frequently having the lustre of steel on the surface. The primitive form of its crystals is the rhomboidal dodeca hedron. 5. The muriate of silver, which has been long known to mineralogists by the name of corneous silver, is found in irregular masses, of a greyish colour, frequently opaque, but sometimes semitransparent. It is soft, and very fusible. Native silver is generally found in irregular shapes; sometimes in masses of no determined form, sometimes branched, occasionally in capillary filaments, and not uncommonly in leaves. Thus it appears in most mines, and particularly in those of Siberia, where Patrin tells us he never met with it crystallized. It is found in the mines of Peru in a vegetable form, imitating the leaves of fern. This variety of figure in native silver is occasioned by a vast number of little eight-sided crystals, so disposed upon each other as to give the whole the appearance of a vegetable. The curved cylindrical filaments, in which form silver is sometimes found, are of various sizes, from the thickness of a finger, to the diminutive size of a hair. Native silver, as we have observed, is seldom found pure, but is generally mixed with other metals; such as gold, copper, mercury, iron, lead, &c. This last metal almost always contains a por tion of silver, though frequently so small as not to be worth the expense of separating it. In the reign of Edward the First nearly 1600 pounds weight of silver were obtained, in the course of three years, from a mine in Devonshire, which had been discovered about the year 900. The lead mines in Cardiganshire have, at different periods, afforded great. quantities of silver. Sir Hugh Middleton is said to have cleared from them 2000 pounds in a month. The same mines yielded, about the year 1745, eighty ounces of silver out of every ton of lead. The lead ores from Brunghill and Skekorn produced also a considerable quantity of silver. The lead only, in one of the smelting houses at Holywell, in Flintshire, produced no less than 31,521 ounces, or 31263 pounds of silver, from the year 1754 to 1776. "There are some lead ores in this country." says Dr. Watson, "which, though very poor in lead, contain between three and four hundred ounces of silver in a ton of that metal. It is commonly observed, that the poorest lead-ores yield the most silver, so that a large quantity of silver is probably thrown away in England, from not having the poorest sort of lead-ores properly assaved." Silver in its mineral state occurs massive, disseminated, in blunt cornered piece, in plates, and in membranes: it is said to occur also in Spanish America in rolled pieces. Its crystallizations are very various, as the cube, octahedron, prism, pyramidal, &c.: the crystals are small and microscopic. It is chiefly found in primitive earths, especially in those which are depositied in beds, though it is not confined to these alone. It is very rarely met with in granite, but not uncommonly in the fissures of micaceous rocks, and in other places of a similar nature, but of more recent formation. In the secondary earths silver often occurs, being found in chalk, slate, &c.; but almost always mineralized by sulphur or arsenic. It is a singular fact, that the situations of gold and silver mines should often be diametrically opposite in point of tempera. ture. Gold is common in the hottest parts of the earth, while we generally find silver mines in the cold regions. Thus, the chief parts of the world where silver is to be met with are, Sweden, Norway, and the higher latitudes near the pole: if we find it in hot climates, it is seldom on level ground; but, on the contrary, raised to a great height, towards the tops of mountains that are perpetually covered with ice and snow. It is thus situated in the Alpine mountains of Europe and America; and such are the mines of Allemont in France, and those of Potosi in the Andes. The principal silver mine in Europe is that of Konigsberg, in Norway, to the north of Christiana. This is the richest, the most important, and one of the most singular mines in that quarter of the globe. The district in which it is situated is mountainous; and the mines are divided into superior and inferior, on account of their relative position. The earth is composed of beds nearly in a vertical position, and running from north to south. Some are composed of quartz mixed with mica, of granite and of chalk: while others are formed of whitish-grey quartz, mixed with fine blackish mica, or else consists of ferruginous rock. These beds are of very considerable thickness, and contain a great quantity of native as well as of mineralized silver. The veins are richer in mineral, and their produce more considerable, where they traverse the beds of ferruginous rock, than in any other part. The most remarkable mine of silver in Spain is that of Guadalcanal, in Andalusia, which was formerly very rich, and well known to the Romans. It is situated in the Sierra Morena, or black mountain, on the confines of Andalusia and Estremadura, fifteen leagues to the north of Seville, and several miles to the north-east of the famous quicksilver mine at Ald Almaden. The mineral obtained here is the ruby silver ore. But it is in the centre of the Andes, in situations which though immediately exposed to the perpendicular rays of the sun, are constantly covered with snow, that nature has most abundantly distributed this metal. In twenty degrees of southern latitude, within the torrid zone, we find the famous mountain of Potosi, situated near the source of the Rio de la Plata. This mountain is one of the most considerable in Peru; its height is immense; and it appears, from the description of travellers, that from top to bottom it is full of veins of silver. When these mines were first discovered, in the year 1545, the veins were so rich as to be almost entirely composed of silver without any mixture. At present, however, the produce is very different, scarcely more than five drachms being obtained from a hundred weight of ore; still, from the great abundance of mineral, the produce is very considerable. According to the observations of several Spanish naturalists, the mountain of Potosi alone, from the time it was first discovered, in 1545, till the year 1638, that is, in the space of ninety-three years, yielded four hundred millions of pesos, or ounces of silver. The analysis of silver varies according to its nature and combinations. Native silver, after being broken down and washed, is rubbed with liquid mercury, which by strong trituration dissolves and combines with the silver. This amalgam is subjected to pressure, to separate, the excess of mercury. It is then distilled, and afterwards beated in a crucible to volatilize the mercury, and the silver remains pure. When silver is combined with antimony and sulphur, the ore is to be strongly roasted, to separate the antimony or sulphur. It is then melted |