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He returned home in the succeeding year, and after assisting his father in a variety of undertakings and perfecting his knowledge of practical mechanics, accepted in 1824, in the hope of benefiting his health, an engagement as mining engineer in South America. Recalled by his father in 1827, he was employed in various labors connected with the construction of the Liverpool and Manchester railway, and in the improvement of locomotives; and in 1829 he assisted in designing and making the successful locomotive, the "Rocket," which was entered in his name. After being engaged on several minor railway lines, he was appointed engineer of the London and Birmingham road, which under his direction was completed in 1838; and thenceforth for many years his time and talents were almost exclusively occupied with similar undertakings at home and abroad. As an engineer he is known by several stupendous works designed in immediate connection with railways, among the most remarkable of which are the high level bridge over the Tyne at Newcastle, the viaduct over the Tweed valley at Berwick, the Conway bridge, and above all the Britannia tubular bridge across the Menai straits, 1,850 feet in length and 106 above high water mark, which Sir James Forbes pronounces 66 a triumph of art and science, an honor to his own age, and a lesson to posterity." In this last undertaking he received important assistance from Messrs. Hodgkinson and Fairbairn with respect to various points of construction and the strength of materials; but the credit of conceiving the enterprise belongs wholly to himself, as well as the rectangular form of the tube, of which there had previously been no example in mechanical construction. He was also employed on railways in Belgium, Norway, Italy, France, and other parts of Europe, and visited Egypt several times to superintend the construction of a road between Alexandria and Cairo, on the line of which there are two tubular bridges, traversed by trains on the roof instead of the inside, as in the case of the Britannia bridge. He also designed an immense bridge across the Nile at Kaffre Azzayat. In British North America he has left a memorable specimen of his engineering skill and perseverance amid unprecedented difficulties in the great Victoria tubular bridge, which crosses the St. Lawrence near Montreal, and was formally opened by the prince of Wales in the summer of 1860. In addition to his railway labors he took considerable interest in public affairs, and during the last 12 years of his life represented the Yorkshire borough of Whitby in parliament, where he was known as an able debater on subjects connected with the railway interests of the United Kingdom. He was also a member of several scientific bodies, and received a great gold medal of honor from the French industrial exposition of 1855. His great wealth was liberally expended, and he enjoyed a reputation for private worth and mechanical ge

nius not less distinguished than that of his father. He published a work "On the Locomotive Steam Engine," and another "On the Atmospheric Railway System.”

STEPPES. See PLAINS.

STEREOSCOPE (Gr. σreρeos, solid, and σкоTε@, to see), an optical instrument contrived for combining into one image, which appears solid, or in relief, two plane representations of a statue, a landscape, or any object or field of objects involving three dimensions. The two separate pictures employed for this purpose are so taken as to show the object or field as it would appear when viewed by each of the two eyes separately. Of such pictures, now known as stereoscopic_views, the effect, and hence the preparation, depend on the two simple principles, that within certain limits of distance the two eyes see at the same time two really unlike pictures of .any solid object or field of objects regarded; and that when two such pictures (for present purposes considered as flat) fall on the retina of the corresponding eyes, the result is a perception of solidity in the objects, or of depth in the field, so presented. If a thin book be held up before the eyes, with the back toward the face, and looked at with the right eye only, the back and much of the corresponding side are seen, and in a certain direction; but on looking with the left eye only, the image of the book and the plane in which it appears to lie shift slightly toward the closed eye, and the back with the other side now becomes visible. The book presents to each eye a somewhat differént surface, and a different position and perspective. On carefully regarding it with both eyes, its apparent position is intermediate to the two before found; the back and in a degree both the sides are now visible, and the book obviously stands in relief toward the eyes. These appearances, alluded to by Euclid, were more definitely observed and described by Galen about 1,700 years since. The familiar but remarkable result is, that we neither see objects double nor as flat surfaces; but always, when not too far removed, as having depth or relief, or as existing in a space which shows this third dimension. (See VISION.) A diagram expressing to the eye Galen's results was drawn by Baptista Porta; and from this, about A. D. 1593, Jacopo Chimenti prepared pairs of drawings (one pair of which is believed to be still preserved in a museum at Lille) intended to show persons as seen by the two eyes separately, and such that, if viewed with the eyes "crossed" by looking at a point nearer to them than are the drawings, so that each eye receives the image of that which is before the other, they are combined, giving a single image in relief. This method, the "ocular stereoscope," is still conveniently resorted to, after some practice, by those who would get the stereoscopic effect of views without employing an instrument. Aquilonius (1613) wrote a volume on the vision of solid objects,

in which this principle was introduced. Mr. Harris (1775) treated on the subject, among other things referring the obviously solid form of the nose as seen by its owner to this effect of vision with two eyes. Prof. Elliott, in 1834, is said to have conceived the plan of an instrument for combining the two single-eye pictures, mentioning it to two or three friends, but not carrying it into execution until 1839. Meanwhile, however, Prof. Wheatstone-to whom is unquestionably due the credit of having devised the first effectual and satisfactory instrument for combining two monocular drawings or pictures into a solid image, as well as of having distinctly brought before the physicists and the public the truth that our actual perception of solidity depends on the combination of two such visual pictures-had exhibited before the royal society in 1838, and also at a meeting of the British association, his "reflecting stereoscope," demonstrating its power to unite pairs of plane geometrical drawings into single and solid forms. Elliott's device was simply a wooden box, 18 inches long, 7 broad, and 4 deep, in the closed or remote end of which the dissimilar pictures were placed. The views he first employed were two representing a leaning cross, with the moon and the branchless stem of a small tree, nearly in line, and as seen from slightly different positions. No mirrors or lenses are required; but on looking into the box, on the "ocular stereoscope" plan, crossing the eyes, the entire view appears to stand forth in solidity or relief. Wheatstone's arrangement, far superior to this, consists of two plane mirrors about 4 inches square, so placed as to make each an angle of about 45° with the axis of the corresponding eye, the two mirrors being thus at right angles to each other, and the drawings on separate slips being presented, each toward a mirror, at the two sides, and at such a distance and angle that the reflected images thrown to the two eyes respectively shall appear to have come from a single object at a corresponding distance behind the mirrors. Thus the two views are in effect superimposed and united, as in natural vision; and if unlike each other in quite or nearly the same way as when received by the eyes from the actual object, the latter will be exactly represented, though it may be on a reduced scale, but appearing in solid form, so that we seem even to look around and beyond it. Two pictures of a bust become in effect a solid bust; the waters of a cataract stand forth in body; a forest, a mountain, or a group of persons comes out in depth, and we look between and beyond the individual objects, as in the natural view. In 1849 Sir David Brewster devised a more convenient form of instrument for combining the two pictures, which is now in common use. In this, two convex lenses properly adjusted are employed for viewing the pictures; or more commonly, parts of a single large double-convex lens, divided in the middle, the thin edges being set

toward each other, and at the ordinary distance of the two eyes, about 2 inches apart. These are placed in a convenient box, into which the observer looks; while beyond them are the slides or double views, which, in case they are opaque, as upon pasteboard, are viewed by reflected, or if transparent, as on glass, by transmitted light. A diaphragm, extending from in front between and to a little way beyond the two semi-lenses, confines the vision of each eye to its appropriate picture; while the lenses, refracting laterally outward to the eyes the light which passes through them, cause the two images to appear as if originating from a single field between the real places of the views, that is, they superimpose these; and at the same time their effect is to magnify the single resulting image. The instrument is known as the "lenticular stereoscope." In the best simple or hand instruments, the semi-lenses being cut from a single lens not less than 3 inches in diameter, and set edge to edge, a single wide aperture serves for both eyes; and the instrument then suits all eyes without adjustment, and allows of an increased field of view.-As no artist can continually and with certainty execute true pictures of trees, persons, or other near objects, with just those differences of surface and perspective which they naturally present to the two eyes separately, it will readily be seen that the stereoscope could be of little use until aided by photography. The pictures employed must be correct, or their faults are exaggerated. Public attention seems first to have been strongly called to the stereoscope as a means of amusement and of the improved representation of objects, by the fine display of lenticular stereoscopes and of appropriate photographic views placed by M. Duboscq in the great exhibition at London in 1851.-It is certain that the perception of solidity or relief, in ordinary vision, is in some way connected with the degree of convergence of the axes of the two eyes (the optic axes) toward the object, or the point on its surface of which at any moment distinct vision is secured. Though we usually judge of distances in a considerable degree, and beyond a certain limit wholly, by light and shade, or aërial perspective, by intervening objects, and by aid of experience, yet when the objects or their parts are within about 250 to 300 feet, there is a sensible difference in the degree of convergency of the optic axes, and hence in the effort to fix the eyeballs in the required positions, and doubtless therefore in the attending muscular sensations. Within some limit, probably that named, the degree and character of these sensations, though unconsciously to him, enable the observer to judge of distances; to determine that some parts of a given object are nearer, others more remote; and thus, perhaps, during the rapid play of the eyes over the object, to obtain that sense of distances which we interpret into solidity of the object. For objects about 250 feet away, the optic an

er.

gle is small, and the sensation of effort slight; for those much beyond this, both these in effect vanish, and relief is no longer a perception, but only an inference; for distances far within the limit, the convergency and sensation become marked. Looking into the stereoscope, the effort to converge the eyes must be made, the sensation of such effort attends, and relief is perceived. It may be in this way that two views of an object a mile distant, and taken by the double camera in common use, its lenses little further apart than the eyes, still show relief when seen in the instrument; and that, as has been stated, even two flat pictures exactly alike have in the instrument been made to afford a view in relief. Brewster argues that to produce perfect stereoscopic effect, the two views should always be taken through lenses of the double photographic camera, having no more than inch diameter, and placed no more than 21 inches apart, or successively through one such lens shifted only to such distance, so as to answer exactly to the pictures furnished in nature to the two eyes. When there are moving objects in the field, and also in taking "instantaneous views," so called, the double camera becomes requisite, or two single cameras, stationed at suitable distance and acting togethFor stationary objects the single camera is conveniently used, the pictures being taken in succession. In taking stereoscopic pictures, it has been customary (though probably the tendency is now back toward the natural conditions) to exaggerate the effect both in respect to distance between stations and to the size of lens. When the plates used are less sensitive, larger lenses may be employed to accelerate the process; sometimes those of 2, 3, or 4 inches diameter. So a broad base or distance between stations of the camera is resorted to for the purpose of exaggerating the relief; for near persons or statues, sometimes as much as 6 to 8 inches; for landscapes, 10 to 20 inches, or even several feet. Thus, strongly differing sides, perspectives, or projections of the objects are obtained. In the double camera, the tubes through which light enters, to be thrown by a convex lens in each on the prepared plates, are not parallel, but inclined to each other at a certain angle, which is usually less in the cameras for taking portraits than in those for views. But in taking the photographic visiting cards, by 4 parallel tubes directed toward the person and view at the same time, 4 pictures are obtained; then, without shifting the person or instrument, 4 others upon another portion of the same slide; and it is unexpectedly found that of these, any right-hand image being suitably placed in the stereoscope with any left-hand image, perfect relief is the result. With near objects, a long base line and marked difference of perspective result in distorting the objects in the direction from before backward (that of depth); all streets, buildings, and similar views extending away from the eye, appear disproportionately long; and in

persons, the head, or an advanced foot, or the dress, is thrown forward to a disagreeable extent. This principle, however, becomes useful in case of bodies so distant that to the eyes, near together as they are, they cannot present the solid form. Remote mountains, buildings, &c., flat to ordinary vision, are made to give unlike views by placing the cameras many feet apart, as they would to a person whose visual organs could be correspondingly separated; and in the stereoscope such views actually give the solid form. This is also the principle of the tele-stereoscope of Helmholtz, in which 4 mirrors are so placed diagonally, the outer pair many feet apart, and the inner at the distance suiting the eyes, that the binocular parallax or angle between the two lines of sight is greatly enlarged, and distinct relief is secured in objects very remote. The angle made by the axes of the two eyes at the point viewed (the "optic angle") is, by both the two methods last named, in effect greatly enlarged-this angle being always a horizontal one-as if the object were very near; but the visual angle of the object, usually regarded especially in the vertical direction, remaining just what it would be with the ordinary base between the eyes, the result is that the judgment of the observer is deceived, and, unless proportionate magnifying power of lenses be employed, the object appears actually diminished in size. The principle of increased distance between stations is availed of in taking stereoscopes of the moon, as has been done by L. M. Rutherfurd of New York, and by W. De la Rue of London. At different seasons the moon presents slightly different faces toward the earth; and two views taken from positions in the earth's orbit 15° apart, and placed in the stereoscope, give a perfect and beautiful globe, its surface diversified with the well known lights and shades of that luminary. M. Claudet, of London, has devised a method in which relief is secured by means of the image of a single picture or object thrown on a ground glass screen, hence termed a stereomonoscope. In this case it is asserted that the image in relief is visible to several spectators at the same time. Another method, by Mr. Maugham, applies glasses of complementary colors, say green and red, to the rays which are thrown by a magic lantern on the screen, and corresponding glasses to the two eyes of each observer, in order to keep separate the rays of the two images; but much light is in this way lost, and the image is faint. Mr. Thomas Skaife, of Blackheath, England, using a small thin lens, of 1 inch focus, has obtained almost instantaneous views which, when magnified, are still extremely well defined and perfect, and which he has termed pistolographs. Enclosed between two plates of glass, and the three semi-fused into one, one of these miniature pictures retains its beauty, while it is protected and preserved; the combination he has termed the chromo-crystal. It is stated that Mr. John Sang, of Kirkcaldy, has recently, by

means as yet kept secret, imparted the stereoscopic effect, or relief, to copies of flat surfaces, such as paintings and engravings.-Several instruments have been invented for the purpose of exhibiting a large number of views in succession, usually involving the revolution of an endless band carrying holders, in which the slides or views are previously placed, and by which they are brought successively into suitable position. Prof. H. W. Dove, by covering slides with printed lines, each one repeated, for one eye commencing evenly, and for the other every alternate line being set in or indented, has secured a perfect imitation of the effect of a double-refracting crystal. He has accordingly proposed to detect spurious bank notes which are copies of the genuine, by observing any suspected note alongside of one known to be genuine in the stereoscope; if the former be spurious, slight misplacements of words or lines, inappreciable to the unaided eye, will distinctly show the double-refractive effect, by an apparent projection of such out of the plane of the paper. Copies of prints or drawings may in like manner be known from the originals; with genuine duplicate notes or prints the effect is not observed. Other applications have been proposed, though not yet probably to any great extent adopted. But as a means of amusement, within the past 10 years the stereoscope has risen to a very prominent place in commerce as well as in art; and experienced artists are already visiting almost every portion of the earth's surface, known or supposed to offer objects of historical interest or scenery of striking character; while groups illustrative of domestic and other supposable scenes and situations are multiplied continually.-Prof. E. Emerson, of Troy university, N. Y., has devised a simple means of remedying a common defect of the lenticular stereoscope. (See the "American Journal of Science," Nov. 1861.) The two semilenses being fixed at the distance from each other supposed to be that ordinarily required, there may still be very great difficulty or even an impossibility of uniting the two pictures on the slides into one impression in relief; and this mainly from two causes-that the pictures are at improper distances apart, the distance between their centres varying from 2 to 3 inches; and that the width between the observer's eyes may also change much. An instrument enabling us to see equally well views whose separation may vary by an inch or more thus becomes a desideratum. In the ordinary arrangement, moreover, the size of each picture is confined to about 3 inches each way, or an area of 9 square inches; the views must be taken under an angle correspondingly small; and even if these be afterward magnified in viewing, still nothing is added in this way to the actual completeness of details. Now, while the lenses employed in the stereoscope are each constant in focal length, yet each will vary in the power of de

flecting a ray, this power increasing from the centre out to the thin edge. Consequently, pictures at such distance apart as to be readily united through the middle part of the lenses, require to be separated more and more as we separate the lenses themselves, looking through their more deflecting portions. This circumstance suggests the means of giving to the instrument a general character, and adapting it to all sorts of views as well as to differences in the width between the eyes. The modification given is that of rendering the lenses movable in a horizontal direction, approaching till the edges touch, or separating as far as the eyes will allow, each lens moving through slightly more than an inch. The lenses must move simultaneously, at the same rate, and in opposite directions; when the right lens moves to the right, the left goes to the left, and vice versa. This is accomplished by fitting the lenses to slide in a brass frame, and attaching the lower edge of each to a nut; within the right nut turns a right-hand screw, and within the left a left-hand screw; and the threads of both screws being cut in the same horizontal rod, both lenses are actuated simultaneously and oppositely by turning the rod by a milled head at one side of the instrument. With this arrangement, the separation of the centres may vary from 2 as far as to 4 inches, or with achromatic lenses to 5 inches; and as an incidental advantage, views may thus be employed which, as taken, cover an area of 20 square inches, or twice that of those in general use.

STEREOTYPE PRINTING. See PRINTING. STERLING. See POUND STERLING. STERLING, JOHN, a British author, born at Kaimes castle, in the isle of Bute, July 20, 1806, died at Ventnor, in the isle of Wight, Sept. 18, 1844. His father, Edward Sterling, had been educated for the Irish bar, had served for a time as captain in the army, was now occupied as a gentleman farmer, and afterward became a leading writer of the London "Times." John was the second of 7 children, 5 of whom died in youth. The family removed to Paris during the peace of 1814, but fled on the return of Napoleon from Elba, and settled in London. At the age of 16 he was sent to the university of Glasgow, whence he was removed in the following year to Trinity college, Cambridge, where he was the chief speaker in the union debating club, and was intimate with a group of young men including F. D. Maurice, R. C. Trench, J. M. Kemble, Charles Buller, and Monckton Milnes. 1828 he and his friend Maurice became proprietors and editors of the recently established "Athenæum," which soon passed out of their hands. Sterling continued to reside in London, and gained the friendship of Coleridge, of whom he was a most enthusiastic admirer. In 1829-'30 he wrote his novel of "Arthur Coningsby" (3 vols., 1833), the hero of which foreshadowed his own career by passing through radicalism, by means of what Car

In

lyle calls the "Coleridgean legerdemain," up to faith in the church, in which he finally takes orders. In 1830 he was married, and.soon after, for the benefit of his health, went with his wife to the island of St. Vincent in the West Indies, where he resided 15 months on a sugar estate. In 1833, under the influence of his former tutor, J. C. Hare, and of Coleridge, he resolved to enter holy orders, was ordained deacon at Chichester in 1834, and at once became curate of Hurstmonceaux in Sussex, where his friend Hare was rector. At the end of 8 months ill health compelled him to retire from the ministry, which he never resumed. He removed to London, where he now first met Carlyle, who soon filled the place of Mentor to him, which had before been held by Coleridge. From this time literature was his chief pursuit. Carlyle describes him as busy but unproductive, roaming among his friends, a welcome illumination to all, his address everywhere pleasant and enlivening. His ill health continuing, in 1836 he went to the south of France, and in the following year to Madeira; part of the years 1838 and 1839 he passed in Italy; visited Madeira again in 1840; and in 1841 settled at Falmouth, from which he made frequent visits to London. Meantime he had contributed to "Blackwood's Magazine" his delightful "Legendary Lore;" wrote for the "Westminster Review," then under the charge of John Stuart Mill; and was engaged on other compositions, in prose and verse. For the purpose of meeting him on his hasty visits to London, the Sterling club had been formed, among the members of which, beside his friends already mentioned, were Tennyson and Sir G. C. Lewis. He published in 1839 a collection of minor poems; in 1841 "The Election," a poem of English life and society; and in 1843 a drama entitled "Strafford." During the last named year both his wife and mother died, and his own health was rendered more precarious by the bursting of a blood vessel. He retired in 1843 to the isle of Wight, and there commenced a poem entitled "Coeur de Lion," which he did not live to complete. In 1848 a collection of his "Essays and Tales," from periodicals, was edited by Archdeacon Hare, with a biography prefixed (2 vols.). The biography dwelt specially upon the religious aspects of his character, as a heroic truth-seeker and a laborious curate. Mr. Carlyle, deeming this the least significant phase of his career, holding that artistic admiration was his forte, and not devotion in any form, and condemning his entrance into the church as "a weak, false, unwise, and unpermitted step," published in 1851 his own "Life of Sterling," one of his best productions and one of the most remarkable of biographies. In 1851 "Twelve Letters by John Sterling" were edited by his relative, Mr. Coningham.

STERNBERG, ALEXANDER Von, baron, a German novelist, born near Revel, in Esthonia, April 22, 1806. He was educated at Dorpat,

and abandoned the study of law for literature. He left Russia in 1830, passed several years in travel, and since 1843 has lived in Berlin. His writings are lively, satirical, and aristocratic. Several collections of his works have been published.

STERNE, LAURENCE, an English divine and author, born in Clonmel, Ireland, Nov. 24, 1713, died in London, March 18, 1768. His parents were both English, and his father, Roger Sterne, a grandson of Dr. Richard Sterne, archbishop of York in the time of Charles II., was a lieutenant in Handaside's regiment, the movements of which, "from barrack to transport, from Ireland to England," young Laurence followed until his 10th year, when he was put to school at Halifax in England. Having been adopted by his kinsman, Mr. Sterne of Elvington, he was in 1733 admitted of Jesus college, Cambridge, where he was graduated in 1736; soon after which he took orders and was presented, through the influence of his uncle, the Rev. Jaques Sterne, to the living of Sutton in Yorkshire, to which preferment a few years later was added a prebend in York cathedral. In 1741 he was married after an ardent courtship of several years, although he lived long enough to cordially hate his wife; and about the same time, through her connections, he obtained the living of Stillington, adjoining Sutton. For nearly 20 years he pursued the career of a rural incumbent, enjoying good health and amusing himself with "books, painting, fiddling, and shooting;" and during this period his only publications appear to have been two sermons, although he probably wrote political paragraphs for the newspapers, and is said to have conducted for some time a periodical electioneering paper in the whig interest. In 1759 he published at York, under the pseudonyme of "Mr. Yorick," the first two volumes of "Tristam Shandy," which were reprinted in London early in 1760. The 3d and 4th volumes appeared in 1761, the 5th and 6th in 1762, the 7th and 8th in 1765, and the 9th in 1767. Long before the completion of the work, the charm and the novelty of the style, abrupt and exclamatory rather than continuous, the whimsical digressions, the exquisite touches of pathos and humor, and its many admirably conceived characters, had taken an extraordinary hold upon the public, and Sterne took his place by the side of Fielding and Richardson and Smollett as a great writer of prose fiction. He was extensively lionized in London, where people were invited a fortnight in advance to dine with him; and Boswell has recorded Johnson's remark that "the man, Sterne, had engagements for three months." The erudition which so greatly astonished the not very learned readers who welcomed the appearance of "Tristam Shandy," will however scarcely stand the test of modern criticism; and it has been shown by Dr. Ferriar in his "Illustrations of Sterne" (1798), that the quaint imagery and the quainter conceits and fancies scattered through

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