to-column connection in a 25story building, which throughout was braced by such brackets, using no diagonal ties.

Special problems arise in very narrow or very tall buildings, as illustrated by the photograph on page 435. In such structures it is apt to be necessary to revert to diagonal bracing, and the overturning moment of the wind sometimes is great enough to require the columns in the lower portion to be enormously heavy. The design of such structures is no different, however, in its principles, from that of a less extreme building. To indicate the magnitude of the steel-frame building field, it may be noted that several single buildings have required as much as 5,000 tons of steel, while in one case a pair of 22-story buildings consumed as much as 11,000 tons.

Cast-iron columns are no longer used in buildings of more than 6 to 8 stories, although a 17-story hotel with cast-iron coumns was built as late as 1903. The serious defect of cast-iron columns for this purpose is the fact that the bolted connections of the beams are unavoidably somewhat loose, which gives the entire structure a dangerous instability. A 12-story building with cast-iron columns collapsed during erection in 1904 in New York City.

Mill and Shed Buildings comprise a large range of most various types of structure, including machine-shop and foundry buildings, train-sheds, etc. The typical mill building consists of a truss roof of 50 to 120 ft. span supported on side columns spaced 12 to 30 ft. apart, with a fongitudinal girder 20 to 40 ft. above the floor, along the inside of each line of columns, to carry the track of a travelling bridge crane. Often jib-cranes are attached to the columns, trolley hoists travel on tracks hung from the trusses, etc., so that the load-conditions are quite various. A cross-section through a representative mill building (Fig. 9), shows the general features. The type of roof-truss there shown, called Fink truss, is used for steel-roof framework very extensively. Diagonal rod bracing in the roof plane, rod or angle bracing in the lower chord, to hold the entire building and especially the crane-track in line, and occasional bays of bracing in the side walls, give ample longitudinal stiffness, while for lateral rigidity a kneebrace between column and truss is usually depended on (in American practice).

of

Train-sheds, exhibition halls. etc., are most often framed with three-hinged arch trusses, roughly semicircular outline, with a tie-rod in the floor to take the thrust of each arch. In struc

tures of this class economy dictates the arranging of the trusses in pairs of 12 to 20 ft. width, the pairs being 35 to 50 ft. apart. Each pair has a full system of bracing and is called a tower; the intermediate parts of the roof then require no bracing, but their purlins merely rest on the adjacent towers. In the gable ends of such shed roofs, a strong horizontal wind truss and trussed vertical studding must be used to held the gable wall from being crushed in by the wind.

Mill and shed buildings are rarely of such character as to require substantial walls, and they are often covered both on walls and on roof with plates of corrugated sheet steel, spanning 5 to 6 ft. between purlins, or with wood planking covered with pre

Fig. 10. Half Section of Battleship "Rhode Island."

pared asphalt-and-felt roof covering, or the like. Concrete slabs

have been much used recently as a more permanent and fireprocf roofing, a weatherproof covering being laid over it.

Ships form a most important field of steel construction, and for several decades past practically all ships have been built of steel. For some details of the framing see Fig. 10 above and also the article SHIPBUILDING. The problem of ship framing is not as exact as that of the bridge, as the forces to be resisted are not so well known. The marine insurance interests, therefore, fix empirical rules for ship framing, which largely govern the arrangement and proportioning of parts. Looking at the section, the frames are curved plate-girders, covered with inner and outer plating on the bottom-the double bottom, which has done so much to increase the safety of vessels, is a result of steel construction. The longitudinal members act as beams, the plating braces the

structure longitudinally, the transverse beams tie the upper ends of the frames together, and the bottom plating and deck act as the flanges of a girder when the ship is subjected to longitudinal bending by riding on waves. Riveted and kneebraced connections are used throughout.

Tank Towers and Gas-holders. -Towers to carry elevated tanks for water-supply are now always built of steel. They consist of four, eight, or mere inclined columns or legs braced together by horizontal struts and crossed diagonal bracing. Gas-holder frames are more complex. Such a frame consists of a circle of standards connected by horizontal circular girders and a full set of diagonal bracing. The gasholder bell, a sectional steel drum often 150 ft. in diameter by 100 ft. high, is guided against the standards by rollers, and transfers to them the wind pressure coming against it. The tank in which the bottom of the bell is immersed is nowadays often made of steel plate, being merely a circular reservcir 15 to 30 ft. high.

Other Applications.-Elevated railways are substantially bridges or viaducts, and the use of steel for their construction is inevitable and indeed alone makes them commercially possible. Subway and tunnel construction also employs steel framing frequently; though the cast-iron shell for shield-driven tunnels is still standard, and in flat-roof subways reinforced-concrete construction is the most modern. Railway cars of steel are now manufactured on a very large scale. These require so many forms to which the ordinary rolled shapes and plates do not adapt themselves, that the desired forms are pressed out of plate steel, being then assembled, of course, by riveting.

Steel enters also into nearly every other field of construction, though to less extent. Pneumatic foundation caissons built of steel; steel sheet-piling; large waterpipes, tanks and stand-pipes, etc. of steel, have wide use. Steel mine-strutting is a newer development. The strength, elasticity, and toughness of steel, the rigidity of steel framework, its permanency under suitable conditions, and its superior lightness for a given duty, which qualities have brought it into use in place of wood and masonry in such a multitude of applications, also ensure its long-continued supremacy in construction.

Permissible Stresses.-The guiding principle in proportioning the sizes of steel structural parts is that no condition of loading may do permanent injury to any part of the structure. The elastic limit' of steel, up to which point

Steel and Iron Construction

it behaves virtually with perfect elasticity, is at about half the ultimate strength, so that by the above principle it is necessary to keep the worst combination of stresses at the weakest point down to about 25,000 to 35,000 lbs. per sq. in., after making due allowance for deterioration and all unfavorable circumstances. There are so many elements of uncertainty, however, that it is customary to remain within certain maximum values of stress, depending on the type of structure. All parts which carry heavy moving loads, as the floor members of bridges, are made heavier by a socalled impact allowance.

In building work, tensile stresses from 18,000 to 20,000 lbs., and compressive stresses of 15,000 to 18,000 lbs. per sq. in., are considered permissible. In columns, the slight bending action of the vertical load is allowed for by using a reduced permissible stress per sq. in. for the direct load; a much used formula is p 17,000-70 Lir, L being the length of the column, and the radius of gyration of its cross-section (0.3 to 0.4 of its least width), both taken in inches. The bending stresses in beams are usually limited to 16,000 lbs. per sq. in., though 18,000 is sometimes allowed. Plategirder flanges are dimensioned for 15,000 to 20,000 lbs. per sq. in. In all cases of tensile stress, net section only is counted, i.e., rivet-holes are deducted.

In bridges, the stresses usually considered permissible are smaller: 15,000 lbs. in tension, 15,000 -50 L/r for columns, 18,000 to 20,000 lbs. per sq. in. for members taking wind stresses only. The floor members of railway bridges are given an increase of section for impact of 100% ordinarily, and truss members or girders are increased by an amount varying (roughly) from 100% in spans less than 50 ft. to 10% at 500 ft. span.

In mill buildings, cranes, and all other kinds of steel structures, the stresses allowed are graded between the above limits, according to the amount of loadimpact and vibration that will occur in the structure. The object ordinarily is to have a factor of safety of 2 between the greatest calculable stresses and the elastic limit of the material.

Rivets are proportioned for a shearing stress not over twothirds the allowed tensile value of plate. The crushing pressure of the rivet against the side of the rivet-hole is customarily permitted to be twice as great, per sq. in. of diametral projection, as the shearing stress allowed per square inch of rivet section. It is specially to be noted that rivets are never required to resist endwise tension,

439 B

whenever it is possible to avoid it; mainly because the shrinkage of the rivet in cooling has already generated a large initial tension, and further tension may result in splitting the rivet head off.

Expansion or Contraction under changes of temperature appears in all steel structures, and where it may lead to harm it must be provided for by expansion joints. Thus, in a fong viaduct, the steel-work will expand about 1 in. in 120 ft. (for 100° F. change between winter and summer), whereas the abutments and piers are fixed in position and cannot yield to the expansion. Therefore one end of every span (or of every second span) is left without firm connection, so that it can slide on its shoe-plate. In longer bridge spans, 150 ft. and over, rollers are usually placed under one shoe, while the other end is bolted down to the masonry. In tall buildings the expansion is free to go on in upward direction, and since stone and concrete expand in about the same ratio as steel, their relative positions remain unchanged. Long mill buildings, unless the heating of the interior keeps them at fairly constant temperature, should have expansion joints. Since every expansion joint is virtually a complete separation in the structure as concerns strength, each section between expansion joints must have full bracing of its own.

Rusting is an eternal enemy of all exposed steel, and therefore painting assumes high importance. Steel is not usually painted in the rolling-mill, but after the individual parts are punched and assembled in the shop they get one coat of paint. In bridge construction, the finished structure is painted immediately after erection with two coats thoroughly applied. Thereafter it must be repainted every two or three years. The strictest requirements for repainting demand that all the old paint be scraped or wirebrushed off, but this is so tedious that it is rarely done. The paints used are nearly all of the linseed-oil class, being mixtures of various pigment powders with linseed oil, turpentine, etc. The resulting hardened paint film is not highly durable. In the worst places, as where a bridge crosses a railway track, with exposure to the cutting action of the exhaust and to the corrosive action of the steam condensation charged with sulphur acids, concrete covering has come into favor, as it seems able to protect the steel perfectly.

Deterioration of steel in service from continued repetition of stress was at one time seriously feared. Experience has brought no such effect to light, however, and several careful tests of old bridges

Steele

have given strong evidence that it does not occur. It may be taken

as certain that the life of a steel structure is limited only by the corrosive action of the elements, and that when steel is kept fully protected against this corrosion it is imperishable. For iron and steel bridges, see BRIDGE. See Birkmire, Architectural Iron and Steel (1897); Skeleton Construction in Buildings (1893); Compound Riveted Girders (1893); Planning and Construction of High Office Buildings (1906); Freitag, Fireproofing of Steel Buildings (1899); Notes on Building Construction, vol. iii. (5th ed. 1902); Wray's Instruction in Construction (1891); Baker's Beams, Columns, and Arches (1892); Rankine's Civil Engineering (1900); and articles on bridges and buildings in Engineering News.

Steele, JOEL DORMAN (183686), American educator, born at Lima, N. Y. He graduated at Genesee College in 1858, and taught school until the outbreak of the Civil War, when he enlisted, serving through the Peninsula campaign. He was wounded at the battle of Seven Pines, and was discharged, with the rank of captain. In 1862-66 he was principal of the Newark (N. J.) High School, and from the latter year to 1872 was principal of the Elmira (N.Y.) Academy. His teaching was distinguished for original methods, and won for him a high reputation. In 1872 he gave up active work as a teacher, and devoted himself to the writing of textbooks. His Fourteen Weeks in Chemistry (1867) was followed by similar works on physics, astronomy, geology, zoology, botany, and physiology. He wrote also, with the collaboration of his wife, the books known as Barnes' Brief Histories. They included ancient, mediæval, and American histories, and became widely popular. He bequeathed to Syracuse University $50,000, which was used to found a chair of theistic science. He was a Fellow of the Geological Society of London, and received the degree of PH.D. from the regents of the University of New York.

Steele, SIR RICHARD (16721729), English essayist and playwright, was born in Dublin. In 1695 he got a commission in the Coldstream Guards, and subsequently became a captain in Lord Lucas's Fusiliers. In 1706 he became a gentleman-inwaiting to Queen Anne's consort, Prince George of Denmark, and in 1707 he was appointed' editor of the London Gazette. As 'Isaac Bickerstaff'-a pseudonym appropriated from Swift - he issued, on April 12, 1709, the first number of the Tatler, which appeared thrice weekly till Jan. 2,

1711. In 1710 Steele became commissioner of stamps. In March, 1711, appeared the first number of the Spectator, which appeared daily till Dec. 6, 1712. Steele's imaginary club in the initial number includes the first sketch of Sir Roger de Coverley, and of the total 555 papers in the periodical, 236 are his. Both in the Tatler and the Spectator, as well as in the Guardian (March 7 to Oct. 1, 1713), he was powerfully supported by Addison (q.v.). In his character sketches, social delineations, and critical discussions, Steele evinces quick obser

Sir Richard Steele.

vation, literary insight, and easy and virile grip of his theme; and if his form is sometimes loose even to crudeness, his treatment is at any rate invariably fresh and enjoyable. In the Guardian Steele diverged into politics, and in 1713 he published a pamphlet entitled The Importance of Dunkirk Consider'd, which provoked Swift's slashing retaliation, The Importance of the 'Guardian' Consider'd. In the same year Steele became M.P. for Stockbridge, resigning his post as commissioner of stamps. The Guardian was now dropped for the frankly political Englishman, which ran to fifty-seven numbers (1714). No. 26 gives the account of Alexander Selkirk which probably suggested Robinson Crusoe. Through his sponsorship for William Moore's work, The Crisis (1714), with reference to the Hanoverian succession, Steele not only prompted Swift's brilliant Public Spirit of the Whigs, but compassed his own expulsion from the House of Commons (March, 1714). The death of Queen Anne presently restored his fortunes, with those of his party. He wrote Mr. Steele's Apology for Himself and His Writings, and he became deputy-lieutenant for Middlesex

and surveyor of the royal stables at Hampton Court. Meanwhile the curious Ladies' Library (frequently mentioned in the Spectator), The Lover, and The Reader, represented his zeal as projector of periodicals. In 1795 he became patentee of Drury Lane Theatre, was elected M.P. for Boroughbridge, Yorkshire, and received knighthood at the hands of George I. Through his political paper, the Plebeian, Steele in 1719 stirred the opposition of Addison, who assailed him in the Old Whig. In 1722 Steele produced in Drury Lane The Conscious Lovers, his most successful comedy. Genial, impulsive, improvident, Steele holds a distinguished place in letters as pioneer of the modern English essay. Austin Dobson prepared an excellent Monograph for the English Worthies Series (1886); and G. A. Aitken produced an exhaustive Biography in 1889, and edited Steele's Plays in 1894.

Steel Engraving. See EN

GRAVING.

Steell, SIR JOHN (1804-91), Scottish sculptor, was born at Aberdeen and apprenticed in Edinburgh as a wood-carver. Having studied sculpture in Rome, on his return he modelled the group of Alexander Taming Bucephalus. Most of his work is in Edinburgh-e.g. the statue of Scott in Scott's monument, the statue of Queen Victoria on the Royal Institution, the statue of Wellington before the Register House, and the Albert Memorial. There are colossal statues, of Sir Walter Scott and Robert Burns, by him in Central Park, New York.

Steel Shapes. See ROLLING MILLS; STEEL AND IRON CONSTRUCTION.

Steelton, bor., Dauphin co., Pa., on the Susquehanna R., 3 m. below Harrisburg, and on the main line of the Pa. R. R. It is chiefly important as a manufacturing centre, making steel rails, bridges, flour, beer, ice, concrete stone, coke, etc. The capital invested in 1906 by the Pennsylvania Steel Co. alone was over $5,000,000. The census of manufactures in 1905 returned 18 industrial establishments, with $19,642,853 capital, and products valued at $15,745,628. The capital invested here was more than tripled in the five years preceding. Steelton is situated in a fine agricultural district. Limestone deposits occur in the vicinity. It was settled in 1865, and incorporated in 1880. Pop. (1900) 12,086; (1910) 14,246.

Steelyard. See BALANCE.

Steen, JAN (1626-79), Dutch painter, called the Molière of painting, for his dramatic and intellectual qualities. His genial,

tolerant expression of life is touched with Hogarthian satire; his best work is masterly in technique and harmonious coloring. The son of a Leyden brewer, he studied under Knupfer, Adrian von Ostade, and Van Goyen. As tavern-keeper he had opportunities of studying life and gratifying intemperate habits. His best work is in Holland and England.

Steen, JOHANNES VILHELM CHRISTIAN (1827-1906), Norwegian statesman; tutor at the Latin school at Bergen (1850), rector at Stavanger (1866). In 1854 he founded the Radical paper Bergens posten; in 1859 he was elected a member of the Storthing, and eventually succeeded Sverdrup as Radical leader. In March, 1891, Steen was entrusted with the formation of a new ministry, but resigned in 1893. His policy was antagonistic to Sweden. He was again premier from 1898 to 1902.

Steeplechasing, originally a trial of speed and jumping powers between two or more horses between one church steeple and another. During the reign of James 1. in England there was some sort of steeplechasing at Newmarket, but details are wanting. There is a record of an Irish steeplechase match in 1752, and to Ireland is due the popularity of the sport. Forty years later the first steeplechase, with more than two starters, was run in Leicestershire, over a course from Barkby Holt to Billesdon Coplow and back, a distance of about eight miles. In the same year (1792) a steeplechase match took place, also in Leicestershire. for 1,000 guineas, between a horse belonging to Loraine Hardy and the best hunter that the Hon. Mr. Willoughby (afterwards Lord Middleton) could procure. The course was from Melton Mowbray to Dalby Wood, a distance of at least nine miles.

There would appear to have been no regularly organized steeplechasing until Thomas Coleman of St. Albans arranged the first regular meeting on March 1, 1831. St. Albans steeplechases have long since died out of the calendar; but since 1839 at Liverpool, or rather Aintree, a suburb of that city, the Grand National has been run about the last week in March, and is still the great English cross-country race of the year. The old type of steeplechase horse (i.e. the improved hunter) is almost a creature of the past, and the cast-off from flat-racing have taken his place. Since the British National Hunt Committee took the sport in hand in 1866, steeplechasing has, however, been greatly reformed. The Grand National, a race worth annually something like £2,000 to the owner of the win

Steer

ner, is now the principal English event. In Ireland, however, there is quite as much interest and excitement in a leaping - race as ever. The nature of the soil permits chasing nearly all the year round, and a large majority of the best jumpers are still bred in that country. In America the steeplechases are generally run at the regular race meetings; one contest each racing day on the regular track and in the infield. Occasional meets are also held at several country and hunt clubs, at which gentleman riders sometimes don silk. The sport is under the direction and rules of the National Steeplechase Association. See Steeplechasing (1889), Badminton Library Series, by A. Coventry and A. E. T. Watson; Racing and Chasing, by A. E. T. Watson (1897); A History of Steeplechasing (1901), by William Blew; The Turf (1898), by A. E. T. Watson; The Great Game (1900), by Edward Spencer; The Steeplechase Calendar (annual); and Ruff's Guide to the Turf (annual).

Steer, P. WILSON (1860), English impressionist landscape and figure painter, born at Birkenhead. The strongest influence in the development of his talent was the work of the French artists Monet, Pizzarro, and Césannes, who were experimenting to solve the problem of suggesting movement in light and atmosphere by the juxtaposition of spots of pure color, unmixed, called the pointillist method. He became the foremost pointillist in England, and from this method his maturer work

has grown. He is an important member of the English Art Club formed for the encouragement of independent, experimental, non-academic painting.

Steering is the operation of directing the course of a vessel. The means of conducting the operation are collectively called the helm, and consist of a rudder and a tiller or steering mechanism. The actual movement of the vessel is effected by the rudder, which, if put to port, causes the stern of the ship to move to starboard--and vice versa. A rudder of ordinary type is a broad, flat structure of wood or iron, pivoted at its forward edge and supported by pintles and gudgeons from the rudder-post or stern-post. Balanced rudders are pivoted about one-third the distance from the forward edge and supported by a collar at the top and a skeg at the bottom. A tiller is a horizontal bar or lever having one end secured to the rudder-head. In large vessels the tiller is operated by some form of steering mechanism. In sailing-ships and small steamers this may consist of a tackle on each side of the

441

tiller, the two ropes going to a steering wheel around the axle or barrel of which they are wound in opposite directions. In large steamers the steering gear is a mechanical contrivance connected to the rudder-head and actuated by a steam, electric, or hydraulic

motor.

The terms used in steering are chiefly derived from the days of hand tillers. Then port the helm meant that the tiller was pushed over toward the port side, causing the rudder to move to starboard. Starboard the helm was the reverse of this. These and other terms which follow are still in use and imply movements of a tiller, though the actual tiller may not exist. Helm amidships means that the tiller is placed fore-andaft. Hard-a-port and hard-astarboard mean that the tiller is as

far a-port or a-starbord as it can

go.

right the helm is to put it amidships after it has been in some other position. To shift the helm is to put it from one side to the other. The helm is a-lee or a-weather accordingly as the tiller (real or imaginary) is drawn to the lee or weather side. To ease the helm is to bring the tiller nearer amidships. The man who steers a ship is called the helmsman, and the one who directs or supervises the steering is usually a quartermaster. To guide the helmsman a compass is placed directly in front of him.

Steevens GEORGE (17361800), English Shakespearean scholar, was born at Poplar, London. His first publication was a reprint from the original quartos of Twenty of the Plays of Shakespeare (1766). He made the acquaintance of Dr. Johnson, and the two collaborated in an edition of Shakespeare's Works, with annotations (1773), almost entirely by Steevens. His life was embittered and his friends alienated by his satiric habit of speech.

Steevens, GEORGE WARRINGTON (1869-1900), English journalist. He joined the staff of the Pall Mall Gazette in 1893, and retired with Henry Cust, the editor, in 1896. During the leisure which followed he wrote a book on Naval Policy (1896), and also Monologues of the Dead (1896). He was sent to the U. S. by the Daily Mail in 1897, and he went 'special' for it to Thessaly, Egypt, the Sudan, India, Germany, Rennes (the scene of the Dreyfus trial), and finally to South Africa, and in almost every case the vivid letters he wrote reappeared in book form. In this way he published The Land of the Dollar (1897), With the Conquering Turk (1897), Egypt in 1898, With Kitchener to Khartoum (1898), In India

Stein

(1899), The Tragedy of Dreyfus (1899), and From Capetown to Ladysmith (1900). He died of typhoid fever during the investment of Ladysmith by the Boers in the war of 1899-1902.

Stefan's Law, a rule connecting radiation with temperature, empirically deduced by J. Stefan of Vienna in 1879. It defines the gain of emissive intensity to be proportional to the fourth power of the absolute temperature of the hot body, assumed to be a perfect radiator. This law, supplied with a theoretical basis by Boltzmann and Planck, has proved eminently serviceable in researches into the solar tempera

ture.

Steffens, HENRIK (1773-1845), German philosopher, naturalist, and poet, born at Stavanger, Norway; became in 1797, at Jena, a disciple of Schelling, and taught at Copenhagen (1802-4), Halle, Breslau (1811-31), and Berlin (1831-45). His lectures in Copenhagen mark the beginning of the romantic movement in Denmark, and made a great sensation. His chief works are Anthropologie (1824), Von der falschen Theologie und dem wahren Glauben (1824), Nachgelassene Schriften (1846). See Peterson's Henrik Steffens (1884), Tietzen's Zur Erinnerung an Henrik Steffens (1871), and Steffens's Own autobiography, Was ich erlebte (1840-45), his best work, English translation by Gage, The Story of my Career at Freiburg and Jena (1863), and republished as German University Life (1874).

Steffens (JOSEPH) LINCOLN (1866), American writer, was born in San Francisco. He graduated (1889) at the University of California, taking special courses in philosophy at Berlin, Heidelberg, Leipzig, and the Sorbonne. Returning to the U. S., he was successively police and financial reporter and assistant city editor on the N. Y. Evening Post, and subsequently city editor of the N. Y. Commercial Advertiser. He gave several years to the study of corrupt polítical machines, and wrote a number of stories dealing with police corruption and politics. From 1901 to 1902 he was managing editor of McClure's Magazine, and from 1902 to 1906 associate editor, when he became associate editor and political reporter for the American Magazine. Mr. Steffens's series of exposés of corruption in American municipal politics began in 1902, and they are contained in his volumes: The Shame of Our Cities (1904), and The Struggle for Self-Government (1906).

Stein, CHARLOTTE VON (17421827), friend and correspondent of Goethe, born at Weimar. For a long time their corre