considerable water should be poured on the silage after the silo is filled. After filling, some persons prevent waste from the spoiling of the top layer by feeding at once. Others place 6 inches to 1 foot of chaff or cut straw on the silage to prevent decay, still others place a layer of tarred paper smoothly over the surface before piling on the straw.

When green materials are ensiled various changes take place. A portion of the carbohydrates, and to a less extent the albuminoids, of the plant is broken down and acids and other simple bodies are formed. At the same time, oxygen is absorbed and carbon dioxide is produced. These changes result in a loss of material which ranges from 4 to 40 per cent. of the total amount originally present. The chemical changes are accompanied by the production of heat, the temperature sometimes rising as high as 66° Centigrade.

Generally speaking, 3 tons of silage are equal in feeding value to 1 ton of hay. On this basis a much larger amount of digestible food can be secured from an acre of silage corn than from an acre of hay. The food equivalent to 4 tons of hay can easily be produced on an acre of land planted to corn. Crops may be more compactly and economically stored as silage than as hay. A silo of 180 tons capacity will contain silage equivalent to 54 tons of dry matter in the same space. Less than 23 tons of red clover hay, containing less than 20 tons of dry matter, can be stored in the same space in a barn.

Consult: Plumb, Silos and Silage, United States Department Agricultural Farmers' Bulletin 32; Thurber, Silos and Ensilage (New York, 1886); Bailey, Ensilage (New York, 1881); Collingwood, Conserved Cattle Food (New York, 1892); Cook, Silo and Silage, Michigan Experiment Station Bulletin 90, ser. 6; Mills, Silos, En

As shown by analysis, the cured silage does not differ materially in composition from the green crop. It is therefore essentially coarse fodder. Silage from legumes is naturally richer in protein than that from corn or other cereals. In some of the mixtures, notably Robertson's silage mixture, the attempt is made to approximate more nearly a balanced ration than is the case with either material alone. Corn silage has the following average coefficient of digestibility: Dry matter, 70.8; protein, 56.0; fat, 82.4; nitrogen-free extract, 76.1; crude fibre, 70.0; and ash, 30.3. Cow-pea silage: Dry matter, 59.6; protein, 57.5; fat, 62.6; nitrogen-free extract, 72.5; crude fibre, 52.0; and ash, 30.3. As regards digestibility silage compares favorably with the green crop from which it is made or the corresponding dry fodder.

The first general use of silage as a stock food was with dairy cattle. The extensive erection of silos in many parts of the United States, however, has resulted in its adoption by many feeders of horses, sheep, and beef cattle. Animals usual, ly eat sound silage with a relish, and reject it only when decay is present. For milch cattle it seems especially well adapted, and the silo has proved an important and economical addition to the dairy farm. Dairy cattle should be fed relatively small amounts of silage until they become accustomed to it. In changing from grass or dry feed to silage, if a regular ration is given, the silage will perhaps slightly affect the taste of the milk for a few milkings, and if the change is from dry feed it may cause too great activity of the bowels. Its use as a food for swine has not been found successful at the agricultural experiment stations.

silage, and Silage (New York, 1895); Woods, Ensilage-Its Origin, History, and Practice (Norwich, England, 1883); Hand Book of Experiment Station Work, United States Department Agriculture, Office of Experiment Station Bulletin, No. 15; King, Silage and the Construction of Modern Silos, Wisconsin Experiment Station, Bulletin 83; Conn, Agricultural Bacteriology (Philadelphia, 1901).

SILAO, sê-lä'o. A town in the State of Guan

ajuato, Mexico, 14 miles by rail from the city of that name (Map: Mexico, H 7). It manufactures cotton and woolen goods, and is the centre of a rich maize and wheat district. Its population, in 1895, was 15,437.

SI'LAS, or SILVA'NUS. One of the early Christians, mentioned as Silas in the Book of Acts, and as Silvanus in the Epistles. Silas may be a contraction for Silvanus, or Silvanus may be a Latin form for the original Silas. He was known as a 'prophet' and leader of the church in Jerusalem, and was one of those chosen to convey the decision of that church to the brethren in Antioch after the council concerning Gentile converts; he remained in Antioch for some time (Acts xv. 22, 32-33). Later, when Paul was about to begin the second missionary journey and had disagreed with Barnabas regarding Mark, Silas became Paul's companion (Acts xv. 36-41). He went with Paul through Asia Minor, passed with him over to Macedonia, shared his experiences in Philippi, Thessalonica, and Berea (Acts xvi.-xvii. 15). He remained at Berea and joined Paul on his return from Athens at Corinth (Acts xvii. 14; xviii. 5). After the close of the second missionary journey

SILAS.

nothing more is known of Silas, unless, as is quite probable, he is the person referred to in 1. Peter v. 12, as the 'faithful brother' of the writer. Consult McGiffert, The Apostolic Age (New York, 1897).

SILAS MARNER, THE WEAVER OF RAVELOE. A story of humble life by George Eliot (1861), Silas, a considered by many her finest work. linen-weaver, wrongly accused of theft, leads an isolated, miserable existence, his one treasure, the savings of years, being stolen by the Squire's In its place, a little child strays into his cottage, and fills his life with joy.

son.

SILAY, sê-li'. A town of Western Negros, Philippines, situated on the northwestern coast 9 miles north of Bacolod (Map: Philippine Islands, G 9). Population (estimated), in 1899, 14,537.

His

SILCHER, zilk'ĕr, FRIEDRICH (1789-1860). A German song-composer, born at Schnaith, Württemberg. He studied with his father and Auberlen, an organist at Fellbach. He taught music while residing at Stuttgart and in 1817 received the appointment of musical director at the University of Tübingen, which position he held until within a few months of his death. Sammlung deutscher Volkslieder contains many of his songs, which have proved great favorites. Among these are: "Aennchen von Tharau," "Morgen musz ich fort von hier," "Ich weisz nicht was soll es bedeuten," "Zu Strassburg auf der Schanz." Among his other works are three books of hymns, Tübinger Liedertafel, and Harmonieund Compositionslehre. He died at Tübingen. Northern

163

SIL/CHESTER. A village in Hampshire, England, about half-way between Reading and Basingstoke. Near the modern village is the site of the old Roman town Calleva Atrebatum. The site is inclosed by the remains of the old wall and broad ditch, but no other ruins of the city are visible above ground, and the place has long been under cultivation. Some slight explorations had been made previously, but the first systematic excavations. were attempted in 1864 by Joyce, who renewed his efforts from time to time. In 1890 the Society of Antiquaries took up the work, and now the greater part of the ancient site has been explored. The museum at Reading has been chosen as the depository of such objects as can be transported. The wall forms an irregular heptagon, Six gates of about 11⁄2 miles in circuit. have been found; the main gates Roman roads which traversed the town from

are on

In the centre

SILENUS.

BLADDER CAMPION.

are best when blanched. Though recommended for cultivation, the plant has not obtained a starry campion of the United States, quite place among garden plants. Silene stellata, the similar to the moss campion (Silene acaulis), a little plant, with beautiful purple flowers is one of the finest ornaments of the higher growing in patches so as to form a kind of turf, mountains of Europe. It occurs also in America. their viscidity. Many species are popularly called catchfly from

SILENT WOMAN, THE. See EPICINE.

SILE'NUS (Lat., from Gk. Zɛinvóc, Seilenos). In Greek mythology, one of the Sileni. These are spirits of the springs, streams, and luxuriant marshy meadows, companions of Dionysus, like satyrs. They seem to belong to the Asiatic worship of the wine-god, and it is in Asia Minor that we find a or the Silenus in various legends, which, while showing the

SILESIA.

first and second Silesian wars.

At the close of the Seven Years' War (q.v.), in 1763, the bulk of Silesia was definitively ceded to Prussia. BIBLIOGRAPHY. Schroller, Schlesien (Glogau, 1885-88); Kosmann, Oberschlesien, sein Land und seine Industrie (Gleiwitz, 1888); Adamy, Schlesien nach seinen physikalischen, topographischen und statistischen Verhältnissen (7th ed., Breslau, 1893); Partsch, Schlesien, eine Landeskunde auf wissenschaftlicher Grundlage (Breslau, 1896); Gruenhagen, Geschichte Schlesiens (Gotha, 1884-86).

SILESIA, AUSTRIAN. A duchy and crownland of the Austrian Empire, bounded by Prussian Silesia on the north and west, Galicia on the east, and Moravia on the south (Map: Austria, E 1). Its area is 1987 square miles. The Sudetic chain enters Silesia from the west, and the Carpathians send off several spurs into the interior from the east, giving the surface an extremely mountainous character. The chief rivers are the Oder and the Vistula, both rising in the province. The climate is raw, but, on the whole, healthful. Agriculture is carried on in the valleys, where good crops of cereals and industrial plants are raised. The mountain regions are chiefly utilized for cattle-raising. Silesia is one of the chief coal-mining districts of Austria, with an annual output of from 4,000,000 to 5,000,000 tons. Favored by its abundance of fuel, Silesia has a number of well-developed manufacturing industries. Ironware, textiles, beer, and spirits are the chief products. Silesia has a Diet of 31 members, and is represented in the Lower House of the Austrian Reichsrat by 12 members. Population, in 1900, 680,529, of whom over fourfifths were Roman Catholic. According to nationality the population of 1890 was divided as follows: 44 per cent. German, 22 per cent. Czech and Slovak, and over 30 per cent. Polish. Capital, Troppau (q.v.). For history, see SILESIA. SILEX (Lat., flint). A generic name formerly used by mineralogists to designate those minerals of which silica is the principal ingredient. SILICA, or SILICIC ACID. See SILICON; QUARTZ.

SILICIDE OF CARBON, or CARBIDE OF SILICON. See CARBIDES.

SILICEOUS ROCKS. A group of sedimentary rocks characterized by quartz as the principal constituent. Sandstone, quartz conglomerate, arkose, novaculite, and chert are the chief varieties of siliceous rocks.

SILICON (Neo-Lat., from Lat. silex, flint), or SILICIUM. A non-metallic element discovered by Berzelius in 1823. Among the ancients minerals rich in silica were used in glass-making, and Becher contended that they contained a peculiar kind of earth, to which he gave the name terra vitrescibilis. In the seventeenth century it was found that such minerals did not change when heated by themselves, and only formed a fusible glass when brought in contact with other bodies. In 1660 Tachenius showed that it possessed acid rather than alkaline properties, as it combined with alkalies, but the true nature of silica remained unknown until Davy demonstrated it in the early part of the nineteenth century. Silicon is the most abundant of all elements in the solid earth's crust, with the exception of oxygen. It is never found in the iso

SILIUS ITALICUS.

lated state, but occurs in combination with oxygen as silicon dioxide or silica (quartz, flint, sand, etc.), and in various minerals in the form of metallic silicates. It is also found in mineral springs and in sea water. It was originally prepared by Berzelius by decomposing potassium silicofluoride by means of potassium in an iron tube at a red heat. When allowed to cool, the mass was treated with water, which dissolved the potassium fluoride, leaving silicon in the form of an amorphous brown powder. This method is still used, but with the substitution of sodium for potassium. The element may also be obtained by the electrolysis of a fused mixture of potassium fluoride and silicofluoride. A graphitoidal modification of silicon is recognized by some, and may be produced by heating amorphous silicon in a platinum crucible; while a third modification, known as crystalline or adamantine silicon, is formed by heating in an earthenware crucible a mixture of three parts of potassium fluosilicate, one part of sodium in small pieces, and four parts of granulated zinc. Silicon (symbol Si; atomic weight, 28.40), when in an amorphous condition, is a lustrous brown powder, which does not conduct electricity and is fusible in a non-oxidizing atmosphere at a temperature between the melting-points of steel and cast iron. The graphitoidal modification consists of shining metallic scales; while crystalline silicon is obtained in the form of grayish-black metal-like leaflets or needles, with a specific gravity of 2.19, and a melting-point Silicon combines between 1100° and 1300° C. directly with a number of the elements, forming silicides. With oxygen silicon combines to form only one oxide, the dioxide, or silica (SiO2), which is an important constituent of the solid crust of the earth and may be artificially prepared by burning silicon in air or oxygen. flint and as sand it has many applications in the Silicon unites with the halogens. Thus, with arts, as in the manufacture of glass, pottery, etc. fluorine, it forms a silicon tetrafluoride, which is a colorless gas that combines with water, forming hydrofluosilicic acid, which in turn unites with bases to form salts known as silicofluorides.

As

SILIPAN, sẽ lê-pän. A Malay tribe in Nueva Vizcaya Province, Luzon; speech, Ifugao. See PHILIPPINE ISLANDS.

SILISTRIA, să-lis'trí-á. A town of Bulgaria, on the right bank of the Danube, 75 miles below Rustchuk (Map: Balkan Peninsula, F 2). In the vicinity are vineyards and tobacco plantations, and the town produces flour and leather a considerable scale. Population, in 1900, 12,133. Silistria was called by the Romans Durostorum and was an important city of Mosia Inferior. It was an important fortress under the Turkish rule and repeatedly baffled the attacks of the Russians.

on

SILIUS ITAL'ICUS, TIBERIUS CATIUS (25101). A Latin poet, whose name appears frequently in Martial and Pliny. He was probably a delator under Nero. In 69 he was consul, and soon after proconsul in Asia. He was rich and luxurious, a dilettante in literature, art, and philosophy, being a member of the Roman school of Stoics and a friend of Epictetus. He starved himself rather than linger with an incurable disease. A Homerus Latinus, or Pindarus Thebanus,

bears his name in acrostic at beginning and end. It is an epitome of the Iliad. He is better known by the Punica, an artificial heavy epic in seventeen books. The poem is edited by Ruperti (1795-98) and by Bauer (1890-92).

SILK (AS. seole, sioloc, sioluc, OHG. silecho, silken robe, probably from OChurch Slav. šelku, silk, from Lat. sericum, silk, neu, sg. of Sericus, Chinese, from Seres, Gk. Enpes, Chinese; cf. Mongol. sirek, silk, Korean sa, sil, sir, silk, from Chin. szě, szú, sz', sei, si, silk). The fibre derived from the cocoon of the silkworm (Bombyx mori), or from some other form of caterpillar or spider, and woven into many useful and ornamental

fabrics.

HISTORICAL SKETCH. Silk appears not to have been well known to the ancients; although several times mentioned in the translations of the Bible, the best authorities deny that it is in the original, or that it was known to the Hebrews. Among the Greeks, Aristotle is the first who mentions it, and he only says that "Pamphile, daughter of Plates, is reported to have first woven it in Cos;" and from all the evidence which has been collected, it would appear that the natives of Cos received it indirectly through the Phoni

cians and Persians from China. The silken webs of Cos found their way to Rome, but it was very long before it was obtainable except by the most wealthy. The cultivation in Europe of the worm itself did not take place until A.D. 530, when, according to an account given by Procopius, the eggs were brought from India (China) to the Emperor Justinian by some monks. In China the cultivation of silk is of the highest antiquity, and, according to Chinese authorities, it was first begun by Si-ling, the wife of the Emperor Hoang-ti, B.C. 2600, and the mulberry was cultivated for the purpose of feeding silkworms only forty years later.

Since its introduction into Europe silk culture has always formed a great branch of industry in Italy, Turkey, and Greece, and it has been carried on to some extent in France, Spain, and Portugal. In England, too, from time to time, efforts have been made to cultivate silk, but with limited success.

In the early days the American colonists devoted much time and labor to the growth of the mulberry tree and the culture of silkworms. In 1732 the colonial Government of Georgia allotted a piece of ground for use as a nursery plantation for white mulberry trees. Lands were granted to settlers on condition that they planted 100 of these trees on every 10 acres when cleared, 10 years being allowed for their cultivation. In 1749 the British Parliament passed an act exempting from duty all raw silk which was certified to be the production of Georgia or Carolina. In the same year an Italian expert was sent to Georgia to conduct a filature-for reeling, doubling, cleaning, and twisting, or throwing silk-and in 1759 the receipts of cocoons at the filature exceeded 10,000 pounds, and the quality of the raw silk was so good that it sold in London as high as three shillings a pound more than that from any other part of the world. After 1759, however, the production of silk in Georgia fell off greatly, though a French settlement at New Bordeaux, on the Savannah River, manufactured considerable quantities of sewingsilk during the Revolution. Mansfield, Conn., be

came, in the latter part of the eighteenth century, an important silk-raising section; and this continued to be a fixed industry in that locality. Pennsylvania engaged in the culture about 1767, and a filature was established in Philadelphia in 1769 or 1770, and in 1771 2300 pounds of maintained some prominence in the industry up cocoons were brought there to reel. This State to the time of the Revolution. From the period of the close of the Revolution up to about 1825 the

silk manufacture in the United States was purely domestic, families making small quantitieshardly ever reaching 100 pounds per annum in a single family.

The importation of silk goods in the meantime had increased enormously, so that in 1821 it amounted to $4,486,924. It was felt that this costly importation should be stayed, if possible, and several Congressional committees investigated the subject, and voluminous reports were made upon it. This brought about the enthusiastic culture of the Morus multicaulis, which dreds of speculators and thousands of private grew into a mania, during whose existence hunbuyers were ruined.

The result of this speculative incident, the financial depression of 1837, and the fact that in 1844 a blight affected all the mulberry trees in the country were disastrous to silk culture in the United States, and the effort to rear silkworms ceased. In California, in 1860-75, the business was largely prosecuted, but did not succeed financially. In 1884 Congress began making appropriations for the encouragement of silk culture in the United States, and these appropriations, expended under the Department of Agriculture, were continued until 1890, when they lapsed and were renewed in 1901. In the meantime considerable silk was grown in Utah under State bounties, and private individuals have raised cocoons and reeled the silk on hand reels for home weaving in many other States. The climate and soil of many parts of the United States seem admirably adapted to silk culture, but as yet there are no commercial reeling estab lishments. The first silk mill on the Western continent was set up at Mansfield, Conn., in 1810. The manufacture was introduced into Philadel

phia about 1815; and as early as 1824 the JacPowerquard loom began to be used there. looms were next introduced, and power-loom From 1831 to weaving was begun about 1838. 1839 a large number of factories were started at Windsor Locks, Conn.; Poughkeepsie, N. Y.; in Philadelphia, and elsewhere, most of which silk-producing locality, beginning about 1838. Burlington, N. J., became an important

failed.

The industry included the culture of the mulberry tree and the raising of silkworms, as well as the manufacture of silk. Hartford, South Manchester (Conn.), Holyoke, Northampton, and Haydenville (Mass.), are among in which silk has the New England towns been manufactured extensively. But the most important centre of this industry in America is Paterson, N. J. (q.v.), where the water power of the Passaic River, facilities for transto offer the best posportation, etc., seem sible conditions for its prosecution. The first silk mill in Paterson was set up about 1838, in the fourth floor of Samuel Colt's pistol factory. This was followed by the establishment of other factories, until in the years immediately succeed