1851, the most important of these being the machine for the manufacture of clothing made by Lerow and Blodgett. This had a curved shuttle, ajustable feed and automatic tension and the baster-plate consisted of a circular hoop studded with pins. The next invention patented that covers a fundamental and important feature was that of John Bachelder, patented 8 May 1849. Bachelder's machine was the first to embody the horizontal table with a continuous feeding device that would sew any length of seam. His invention consisted of an endless leather belt set with small steel points projecting through the horizontal table and penetrating the material to be sewed, carrying it along intermittently at a proper time to meet the action of the needle.

Elias Howe, Jr., began his experiments in 1843 and secured his first patents 10 Sept. 1846. Howe's principal improvements were the shuttle, producing the lock-stitch, and the feed motion. Later, Howe made other improvements, but the machine bearing his name was not patented until 1857. Howe's invention consisted of the combination of the eye-pointed needle with a shuttle for forming a stitch and an intermittent feed for holding and carrying the material forward as each stitch is formed. The mechanical device for the feed was called the "baster-plate," and the length of the seam sewed at one operation was determined by the length of this plate. The material to be sewed was hung by pins to the "baster-plate" in an upright position and if the seam to be sewed was of greater length than the plate it was necessary to rehang it on the plate, which was moved back to position in the same manner as a log is carried back and forth in a saw-mill.

In 1847 Allen B. Wilson, then working as a journeyman cabinet-maker in Adrian, Mich., conceived the idea of a sewing machine, although he had never heard of one. He did not complete full drawings of his machine until the latter part of 1848. Early in 1849 he determined to build a model, and began, on 3 Feb. 1849, the construction of his first machine, which he completed in about 60 days. Having been compelled, by lack of means, to construct every part of the machine himself, the iron and steel as well as the wood, although he was not a practical machinist and lacked suitable tools for the metal work, the machine was consequently of imperfect construction and could not illustrate in the best manner the principles of his invention. It worked, however, and with it were made dress waists and other articles that severely tested its capacity. This machine made the lock-stitch, the lower thread being carried by a double-ended shuttle. The machine contained the first automatic feed movement ever produced and was the first that could sew curved seams or turn a sharp angle. Without such a device, the machine would have been a practical failure, as Howe's really was, and as well all others until Mr. Wilson's inventions. His first device was what is known as the "two-motion feed," to distinguish it from his "four-motion feed," a still more effective device afterward invented by him. The "twomotion feed" consisted of a horizontally reciprocating tooth surface (the pitch of the teeth being forward) engaging the material at all times, and while the needle was in the material moving back to take a new stroke. A patent

on this machine was granted Mr. Wilson on 12 Nov. 1850. Wilson had, while in New York, come into contact with a Mr. Wheeler who had invented the revolving hook for handling the upper thread below the plate and forming the stitch. He constructed a model of a machine containing a rotary hook and reciprocating bobbin, gave all his energies to perfecting the new machine and obtained a patent for it 12 Aug. 1851. Joined by Newton the three men formed the firm of Wheeler and Wilson.

It is a remarkable coincidence that on the same day a patent was granted to Isaac M. Singer for his first machine. The main features of the Singer machine were its straight needle, working at the extremity of a stationary overhanging arm, and its feed, consisting of a roughened wheel. A straight shaft in the overhanging arm imparted the motion to the needle, and the shuttle was driven in its race below the feed table by a mechanism deriving its motion from the shaft by means of toothed gearing. The feed consisted of an iron wheel with a corrugated surface, the top of which was slightly elevated above the level surface of the table. By an intermittent motion the feed carried the cloth forward between stitches without injury to the fabric. This device permitted the cloth to be turned in any direction by the operator while sewing, which was impossible with the styles of feed which perforated the goods. The material was held in place by a presser foot alongside the needle. This presser foot embraced an important feature possessed by no other sewing machine up to that time-the yielding spring, which would permit of passage over seams, and adjust itself automatically to any thickness of cloth. It was claimed that this was an improvement over Mr. Wilson's first feed, in that there was no backward motion while in contact with the cloth. It had, however, the disadvantage of touching the cloth only on a small portion of its periphery theoretically at only a point, and practically only a little more. It was claimed by Messrs. Wheeler and Wilson to be really an infringement of Wilson's patent, the principle of which was the holding of the cloth between a roughened or toothed surface on the under side and a smooth surface touching it with an intermittent motion, permitting the turning of the cloth in either direction while the machine was in motion; and this claim was sustained by the court.

On 19 Dec. 1854, a patent was issued for Mr. Wilson's celebrated "four-motion feed," so called from the peculiarity of the device by which the flat-toothed surface of the feed, being in contact with the cloth, is moved forward, carrying the cloth with it; then drops out of contact with the cloth, is moved backward and then rises up against the cloth and is again ready for the first motion. This device solved the problem of a thoroughly practical and effective feed, and was soon generally adopted and has become the feed motion of all makes of sewing machines. This feed motion, although it was not patented until this late date, had been long previously invented by Mr. Wilson, and was described in his application for a patent in 1851, but the claim was not pursued for the reason that he believed at the time that he had been anticipated by W. O. Grover, of the firm of Grover and Baker. It

was ascertained afterward, however, that Mr. Wilson was really prior in the invention, and, without contest on the part of Mr. Grover, the patent was granted to Mr. Wilson. This machine was invented by Grover and Baker on 11 Feb. 1851 and had a double-loop stitch made by a combination of a circular reciprocating under needle and a curved upper needle with an eye near the point. This eliminated both shuttle and bobbin and rendered it possible for the upper and under threads to be taken from commercial spools. These machines, though once popular, are not now manufactured.

In 1855 litigation arose involving the three principal sewing-machine companies then in existence, each claiming that the others were infringing upon certain of their patent rights, and numerous suits were instituted, more particularly by Howe, whose patents were so skilfully drawn that he claimed all others were infringements.

In 1856 the three principal sewing-machine companies Wheeler and Wilson, Singer and the Grover and Baker - formed a combination. It was contracted by the three companies and Mr. Howe that they would stop their litigation, and, with a fair payment to each other and to Mr. Howe for special rights, would carry on the business with only honorable competition. They finally agreed to license any responsible person who should propose to engage in the manufacture of a good machine on the payment of a royalty, which for several years was $3 on a machine.

The next machine to be put on the market was the Willcox and Gibbs. This machine, which had a rotating hook for using a single thread to make the twisted loop-stitch, was first patented in June 1857 by James E. H. Gibbs, a farmer of Millpoint, Va. Later James Willcox, of Philadelphia, added some further improvements, and the machine then became known as the Willcox and Gibbs. Several years afterward an automatic tension was placed on this machine by Charles H. Willcox.

While the manufacture of machines for the home has been developing and progressing, those for manufacturing purposes have in no less a degree been brought to a state bordering on perfection. The most recent development is the oscillating shuttle machine of the Singer Company which makes up to 50 stitches per second with scarcely any apparent friction. The single thread chain-stitch machine is faster than the double thread lock-stitch, making up to 4,000 stitches per minute. There are now machines for making or which have special attachments for making. every conceivable article of clothing, upholstery, embroidery, leather goods, etc. We have the button-hole, the button-sewer, the French-knot, the faggoting, feather-stitching, hemstitch, side and boxplaiters, corset machines; the cylinder for seam work on sleeves, trousers, bootlegs, leather buckets, etc.; machines for embroidery, smocking, carpet, awnings, tents, etc.; the single and double-needle machines and those with four, six and eight needles for glove work, special machines for overalls, sail-making, flag-making and a host of others too numerous to mention. A special class known as high-speed machines is used in factories where clothing is made in

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quantity. They are run by individual dynamos. Many of the machines may be used for several different purposes by simply changing the style of feed motion, presser foot, needle, etc., while the other parts of the mechanism remain substantially the same. There have been several thousand patents granted on sewing machine appliances and attachments.

The production of sewing machines has become a wonderful industry in the United States, which leads the world in their manufacture. In 1914 there were 46 concerns engaged in the industry, capitalized at $34,446,624; employing 14,308 wage-earners, with wages of $8,860,843; cost of material used, $7,359,664; and the value of their production was $21,391,917. Besides these there were 4 establishments making sewing-machines cases, with an invested capital of $6,425,153 and employing 3,699 hands; producing goods annually to the value of $5,845,663. In the same year the exports of sewing machines with and without cases amounted to $8,658,762. Consult Hasluck, P. N., Sewing Machines: Their Construction, Adjustment and Repair' (London 1905).

SEX IN PLANTS. See PLANTS, SEX IN. SEXAGESIMA (seks-a-jěs'i-ma) SUNDAY, the second Sunday before Lent. See QUINQUAGESIMA.

SEXTANT, a portable instrument for measuring the altitudes of the heavenly bodies above the horizon, or their angular distance as seen in the sky. It was invented independently by Thomas Godfrey, of Philadelphia, and Captain Hadley of the British navy, about 1730. The principles on which it works will be seen by a study of Fig. 1. C is a plain flat mirror, of which the polished side is turned downward P.

and toward the left. H is a flat plate of polished glass through which an eye placed at E may view a distant object in the direction K by light coming through it in the direction of the dotted lines. Light emanating from another object O or P and falling on the mirror C will, where the mirror is properly directed, be reflected along the line CH and, in striking the glass plate H, a certain portion of it will be reflected in the direction HE, so that the observer with his eye at E will see both the objects K and O or P in coincidence. If the mirror C is set parallel to H as in the figure, the rays KE and OC will be parallel, and may, therefore, be considered as emanating from the same object at an infinite distance.

Thus the eye will see two images in the mirror as if together. But if the mirror C be moved into a different direction, that shown by the dotted line AB for example, the direction of the ray, the direction of the line PC, the rays along which are reflected to H, will deviate from OC by double the angle through which the mirror has turned. This doubling is caused by the fact that the angles of incidence and reflection are both changed by the motion of C. It follows that if the observer can measure the angle between the mirror C and H, doubling this angle will give him the difference of direction between the rays coming from K and from P.

The sextant is used to measure this angle. The essential parts of it are shown in Fig. 2. The part ABC consists of the arc AB round C as a centre and firmly fastened by the radii CB and CA which are again firmly connected by a framework not shown in the figure. To this framework is attached the fixed plate of glass H, of which the lower half is silver while the upper half is transparent. T is a telescope, also firmly fixed to the frame, through which the eye looking in at E may see a distant object through the transparent portion of the mirror, and at the same time see any other object by the light reflected from the silvered part. The arc AB is graduated to degrees and fractions as shown by the figures. Owing to the doubling of the angle, the measures on the arc BA are also double. That is to say, this are is only 60 degrees in length, but is divided into 120 degrees, so as to show the actual altitude of the object observed.

RM is a movable arm carrying a mirror C called the index glass, fixed to it perpendicularly at its upper end. The arm revolves around C as a centre. At its lower end there is an index mark and vernier by which the position of the arm with respect to the graduations on the arc may be determined.

The altitude of a heavenly body at C is then measured by the observer taking the instrument in his hand and holding it in a vertical position, with the telescope ET horizontal, so that the sea horizon may be seen through the transparent part of the horizon glass H. The

observer facing in the vertical plane of the sun or other object then turns the arm RM around the centre C until he brings the sun into sight, through its rays being reflected first from C and then from H. When the limb of the sun is thus made to coincide with the horizon, the angle through which the arm RM has moved from parallelism is shown by the position of the index on the graduated arc BA, which is then determined by the vernier.

In ordinary use the navigator never has to measure angles exceeding 90 degrees. In this case the arc BA need only to be 45 degrees in actual length. The instrument is then called a quadrant. This was the original form used by Hadley.

For very accurate use the arc is extended down so as to form a complete circle. A special device is employed to bring about the proper reflection of the light; but the reflecting circle, as the instrument is called, is too complicated to admit of common use by the navigator.

SIMON NEWCOMB.

SEXTET (from Lat. sextus, sixth). In music, a composition for six voices or instruments, or for voices with instrumental accompaniment. Instrumental sextets are generally compositions in sonata form.

SEXTON, Alexander Humboldt, English metallurgist: b. London, 11 Sept. 1853. He was educated at the Royal School of Mines, London, the Royal College of Science, Dublin, and at the universities of Glasgow and Edinburgh. He was lecturer on chemistry and metallurgy at the Manchester Technical School in 1882-84; and from 1884 until 1909, when he retired, he was professor of metallurgy at the University of Glasgow and at the West of Scotland Iron and Steel Institute. Author of Elementary Chemistry); Fuel and Refractory Materials'; 'Alloys'; Chemistry of the Materials of Engineering,' etc.

SEXTON, Frederick Henry, Canadian engineer and educator: b. New Boston, N. H., 9 June 1879. He was educated at the Massachusetts Institute of Technology and was professor of metallurgy there in 1901-02. He was assistant professor of mining and metallurgy at Dalhousie University, Halifax, Nova Scotia, in 1903-07; and since 1907 has been president of the Nova Scotia Technical College. Since 1916 he has also had charge of the vocational training school for returned soldiers of the Quebec and Maritime provinces. He is author of many technical papers.

SEXTON, a church officer whose duties consist in taking care of the church generally, to which used to be added the duty of digging and filling up graves in the churchyard, when the church had a cemetery attached to it. In the United States the sexton is also very often an undertaker, and thus continues in a form different from the old-time sexton, to attend to the interment of church members. The term sacristan, of which sexton is a corruption, applies more particularly to an official in the Roman Catholic and Anglican churches, who has charge of the sacristy and its contents, and of the vestments worn during the service. He occupies a considerably higher rank than the

ordinary sexton, and in English cathedrals is often a minor canon

SEXTUS (surnamed EMPIRICUS, from his belonging to the empiric school of medicine) was a sceptic who flourished in the first half of the 3d century. He was a Greek by birth, and lived at Alexandria and Rome. Scepticism appears in his writings in the most perfect state which it reached in ancient times. (See SCEPTICISM). We have two works by him, written in the Greek language, and they are the source of our knowledge of the Greek sceptical phi-. losophy. One of them entitled Outlines of Pyrrhonism in three books, explains the method of Pyrrho; the other, entitled 'Against the Mathematicians, is an attempt to apply that method to all the prevailing philosophical systems and other branches of knowledge. Consult the edition of his works by J. A. Fabricius (Leipzig 1718) and by Bekker (Berlin 1842); also Brochard, 'Les sceptiques grecs' (Paris 1887); Christ-Schmid, Geschichte der griechischen Literatur) (Vol. II, pt. 2, Munich 1913) and Pattrick, 'Sextus Empiricus and the Greek Sceptics' (Cambridge 1899).

SEXUAL SELECTION, a term invented by Darwin to denote a special phase of natural selection, depending on a competition between rival males, in which a premium is set on those qualities which favor their possessors in securing mates. This competition takes two forms: On the one hand, rival mates, for instance, stags or gamecocks, fight with one another and the conquerors have naturally the preference in mating; on the other hand, rival males sometimes seem to vie with one another in displaying their attractive qualities before their desired mates, who, according to Darwin, choose those that please them best. Darwin gives the following summary of his theory:

"It has been shown that the largest number of vigorous offsprings will be reared from the pairing of the strongest and best-formed males, victorious in contests over other males, with the most vigorous and best-nourished females, which are the first to breed in the spring. If such females select the more attractive and, at the same time, vigorous males, they will rear a larger number of offspring than the retarded females, which must pair with the less vigorous and less attractive males. So it will be if the more vigorous males select the more attractive and, at the same time, healthy and vigorous females; and this will especially hold good if the male defends the female, and aids in providing food for the young. The advantage thus gained by the more vigorous pairs in rearing a larger number of offspring has apparently sufficed to render sexual selection efficient.'

In regard to the second aspect of sexual selection, in which the females are believed to exercise some choice, giving the preference to those suitors which have brighter colors, more graceful forms, sweeter voices or greater charms of some kind, there is no little difference of opinion. Darwin indeed believed strongly in the female's choice and referred to this process of selection many of the qualities which distinguish male animals. The females "have by a long selection of the more attractive males added to their beauty or other attractive qualities." On the other hand, Alfred Russel Wallace maintains a very different position. "There is," he says, "a total absence of any evidence that the females admire or even notice the display of the males. Among butterflies there is literally not one particle of evidence that the female is influenced by color or even that she has any power of choice, while there is much

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direct evidence to the contrary." Against this, G. W. and E. G. Peckham, in their careful essay on sexual selection in spiders, state that they have in the Attida "conclusive evidence that the females pay close attention to the love dances of the males and also that they have not only the power, but the will, to exercise a choice among the suitors for their favor." Some observers of birds are also confident that the females choose the more musical or otherwise attractive males. But again Wallace maintains that the fact that every male bird finds a mate "would almost or quite neutralize any effect of sexual selection of color or ornament; since the less highly colored birds would be at no disadvantage as regards leaving healthy offspring."

The theory of sexual selection is of considerable importance in a general theory of evolution. This may be illustrated in reference to the bright plumage of many birds. If we postulate successive crops of variations (which cannot at present be completely rationalized), if we acknowledge that there is really "preferential mating" among birds (which is not readily proved or disproved), if we believe that the females are sensitive to the slight excellences which distinguish one suitor from another and that their choice of mates is determined by these excellences (which Wallace emphatically denies), then we may say that the greater brightness of male birds may have been evolved by sexual selection. This was Darwin's opinion. The brighter males succeeded better than their rivals in the art of courtship; the variations which gave them success were transmitted to the offspring; gradually the qualities were established and enhanced as secondary sexual characters of the species. But Wallace interpreted the facts quite otherwise. relatively plain plumage of the female birds was due to natural selection, eliminating those whose conspicuousness during incubation was fatal, fostering those whose coloring was protective. Just as Daines Barrington, a naturalist, still remembered as the correspondent of Gilbert White, suggested (1773) that singing birds were small and hen birds mute for safety's sake, so Wallace maintained that female birds had forfeited brightness as a ransom for life.

The

The doubts and difficulties arouse scepticism as to the thoroughness of the explanations of secondary sexual characters suggested either by Darwin or by Wallace. It is not surprising, therefore, to find Mivart's explanation of the beauty of males as the direct expression of an internal force, or Mantegazza's hints as to physiological explanation of the sexual divergence, or Brook's reference to "something within the animal which determines that the male should lead and the female follow in the evolution of new breeds." Geddes advanced further, endeavoring to interpret the secondary sexual characters as outcrops of the relative preponderance of anabolism and katabolism characteristic of females and males respectively. Gay coloring sometimes at least due to pigmented waste products is regarded as a characteristic expression of the predominantly katabolic or male sex and quiet plainness is equally natural to the more anabolic females. But this theory, which seeks to rationalize the variations which Darwin simply postulated, is by no means inconsistent with a recognition of sexual selection as an accelerant directive process in the evolu

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tion of male brightness, or of natural selection as a retardative directive process eliminating disadvantageously conspicuous females.

Wallace in his later works advanced toward a rational interpretation of the variations which he was previously content to postulate as facts. For he says that "ornament is the natural outcome and direct product of superabundant health and vigor," and is "due to the general laws of growth and development." It seems to some that this mode of interpreting characters is of far-reaching importance and that it affects not only the theory of sexual selection but that of natural selection as well.

To sum up, the problems involved in sexual selection are (1) what physiological conditions explain the secondary sexual characters which so often distinguish males and females; (2) to what extent and in what degree of refinement does preferential mating occur; and (3) to what extent has sexual selection guided the differentiation of the sexes alike in distinctive qualities and in æsthetic sensitiveness? Before these problems can be adequately solved many more facts must be accumulated.

Bibliography.- Bateson, W., 'Mendel's Principles of Heredity) (London 1909); Cope, E. D., ‘Origin of the Fittest' (London 1887); Cunningham, J. T., 'Sexual Dimorphism' (London 1900); Darwin, C., Origin of Species' (new ed., London 1906); id., 'Descent of Man and Selection in Relation to Sex (new ed., New York 1909); Dewer and Finn, The Making of Species' (New York 1909); Geddes, P., and Thomson, J. A., The Evolution of the Sex (2d cd., London 1901); Lock, R. H., 'Recent Progress in the Study of Variation, Heredity and Evolution' (London 1906); Osborn, H. F., 'From the Greeks to Darwin' (New York 1894); Peckham, G. W. and E. G., Sexual Selection in Spiders' (Milwaukee 1890); Poulton, E. B., Charles Darwin and the Theory of Natural Selection' (London 1896); id., 'Essays on Evolution' (Oxford 1908); Seward, A. C., 'Darwin and Modern Science (Cambridge 1909); Vernon, H. M., Variations in Animals and Plants' (London 1903); Vries, H. de, 'Species and Varieties, Their Origin by Mutation (Chicago 1905); id., The Mutation Theory (London 1910); Wallace, A. R., 'Darwinism (2d ed., London 1890); Weismann, A., The Evolution Theory' (London 1904); Wilson, E. B., 'Recent Researches on the Determination and Heredity of Sex) (London 1909).

SEYCHELLES, sa-shěl', a group of islands in the Indian Ocean, belonging to Great Britain. Their formation is peculiar, as they are the only tropical islands of granite structure. The archipelago comprises 80 islands, rising precipitously from the water to a height of 2,998 feet in the largest of the group, Mahé, which has an area of 551⁄2 square miles. Smaller islands of the group are Praslin, Silhouette, La Digue, Curiense and Felicité. Formerly the group was administered from Mauritius but in 1888 the office of administrator was created, an executive council of two ex officio members and one nominated member was appointed and a legislative council of six members. In 1915 the revenue was $127,000, the expenditure $155,500 and the debt $60,000. Exports in 1915 were valued at $462,340 and imports at $280,000. Mahé is central and, with a few of the others,

is inhabited. The white sandy beaches are enclosed by coral reefs. The soil is fertile, the climate temperate. There are many brooks and streams. The islands are covered with verdure (enormous ferns, sensitive plants and palms grow) and valuable woods, adapted to cabinet work or shipbuilding. Vanilla, coffee, cocoa, spices, tobacco, corn, tropical fruits and vegetables are grown. The exports are the fibres, nuts and oil of the cocoanut palm; vanilla, soap, tobacco, tortoise-shell and vacoa bags. The imports are cotton, coal, wine, coffee and cotton goods. Coco-de-mer (q.v.) is peculiar to Praslin. Enormous tortoises of the edible sort are common. The adjacent seas contain numerous fish, some of gorgeous colors. The inhabitants construct their homes of a species of coral which glistens like marble and is hewn into massive blocks. The chief harbor is Port Victoria, on Mahé Island. There is much land suitable to, but not as yet under, cultivation. The Seychelles were discovered by the Portuguese and first colonized by the French (1743), of whom the present inhabitants are descendants. The British captured the islands in 1794 and at the peace of 1814 they were ceded to them. Pop. about 24,000. Consult Belcher, E., 'Account of the Seychelles'; Fauvel, A. A., 'Bibliographies des Seychelles' (1908); Gardiner, J. S., The Seychelles'; Hartman, 'Madagascar und die Inseln Seschellen) (Leipzig 1886).

SEYCHELLES COCOANUT, a palm (Lodoicea sechellarum), peculiar to the Seychelles Islands, sometimes 100 feet high, crowned by immense palmate leaves, which make good material for hat plaiting and basketry, and when mature are used for house partitions and for thatching. The fruits are gigantic in size, sometimes weighing as much as 50 pounds and were anciently supposed to grow on submarine palms, since they were found only when washed ashore on Asiatic coasts. This circumstance caused many superstitions to arise, especially that they were a powerful cure for snake poison, and they, therefore, commanded high prices in the East and were called coco-der-mer, sea, double or Maldive cocoanuts. There are from one to four stony nuts in a husk, each being deeply lobed at each end. This floating apparently double nut may have given rise to the types of twin boats. The unripe fruit is edible and the hard black shell of the nuts is carved into ornaments and fakers' drinking cups. See PALMS.

SEYFFARTH, zi'färt', Gustave, American educator and Egyptologist: b. Uebigau, Saxony, 13 July 1796; d. New York, 17 Nov. 1885. He was educated at the University of Leipzig and under Champollion in Paris. He was professor of Oriental archæology at the University of Leipzig in 1825-55, afterward emigrating to the United States. He was professor of archæology and exegesis at the Concordia Lutheran Theological Seminary, Saint Louis, in 1855-71. He then retired and lived in New York. He was a lifelong student of Eygptology and made many translations. Author of De Sonis literarum græcarum tum genuinis tum adoptivis libri duo' (1823); Systema Astronomiæ Ægyptiaccæ' (1833) "Theologische Schriften der Alten Aegypter' (1855); Summary of Recent Discoveries in