near the skirts of it, had the world totally to begin again. Who could have imagined that a breastwork which had stood for ages should at length give way? or that these subterraneous floods, which had been bedded in darkness since the memory of man, should ever have burst from their black abode? This dreadful inundation, though the first shock of it was most tremendous, continued still spreading for many weeks, till it covered the whole plain, an area of 500 acres, and, like molten lead poured into a mould, filled all the hollows of it, lying, in some parts, thirty or forty feet deep, reducing the whole to one level surface." (Gilpin's Observations on the Mountains and Lakes of Cumberland.)-In order to clear the arable and pasture land of this accumulation of moss, Mr. Wilson, from Yorkshire, adopted a very ingenious plan. He formed, in the higher grounds, two large reservoirs, which he filled with water, the whole force of which he directed against a large knoll in front of Netherby house, and afterwards against the accumulated masses, which he succeeded in washing away into the channel of the Esk. Doctor Graham, of Netherby, had sent for a person to survey the ground, and estimate the expense of removing the moss in the ordinary way. The estimate was £1300; but while the matter was under consideration, Wilson suggested that it might be done cheaper; and by the method which we have mentioned, he effected it for less than £20.-Another account of the eruption of this moss, by Mr. J. Walker, of Moffat, will be found in the Philosophical Transactions for 1772, vol. lxii, p. 123. According to Mr. Walker, the mossy ridge was reduced no less than twenty-five feet; but what is not easily explained, he makes the eruption take place on the sixteenth of December, 1772, whereas Gilpin places it on the thirteenth of November, 1771. Mr. Walker mentions the remarkable case of a cow, the only one, out of eight in the same byre, that was saved. It had stood sixty hours up to the neck in mud and water; and when it was taken out, it did not refuse to eat, but it would not taste water, nor even look at it, without manifest signs of horror. It was soon, however, reconciled to it, and was then likely to recover. SORBETTO. (See Sherbet.) SPASM (from onaw, to draw); a cramp, or convulsion. An involuntary contraction of the muscular fibres, or that state of the contraction of muscles which is not spontaneously disposed to alternate with relaxation, is properly termed spar When the contractions alternate with relaxation, and are frequently and preternaturally repeated, they are called convalsions. Spasms are distinguished by authors into clonic and tonic spasms. Ir clonic spasms, which are the true convulsions, the contractions and relaxations are alternate, as in epilepsy; but in toni spasms, the member remains rigid, as i locked jaw. (See Convulsion, and Tetanus.) SPASMODIC CHOLERA. (See Cholera in this Appendix.) SPECTRES. (See Visions.) SPINNING FRAME. (See Cotton Mensfacture.) SPIRITS. (See Visions.) Spirits.) (See Famibe SPURZHEIM, Gaspard. Since the publication of the eleventh volume, whici contained an imperfect notice of this di tinguished man, he has visited this country, and paid the great debt of nature ir the midst of us. He arrived in the U. States in August, 1832, with the intention of remaining about two years in the country, lecturing in the principal town, and visiting the different tribes of Indians within our territory. He began his lectures in Boston, where he delivered one course on the anatomy of the brai... designed principally for medical men. He had nearly, likewise, completed two popular courses of lectures on phrenology. one in Cambridge, and the other in Boston, when death interrupted his labors. Nov. 10, 1832. From the beginning of his popular course in Boston, the number of his hearers continually increased, and, towards the latter part of the time. had become so great that it was found necessary to change the room in which they were commenced for a larger hal. Doctor Spurzheim had, during his short residence in Boston, won the affection of a large number of his hearers, by the urbanity and gentleness of his manners, and the benevolence and enlarged philat thropy of his sentiments and disposition. while his elevated morality and scientitir acquirements commanded the genera respect. His funeral obsequies were. therefore, solemnized in one of the churches of that city; and a eulogy was pronounced over his remains by professor Follen, of Harvard university. His body, which had been embalmed, was depos ited in such a situation that it might be transmitted to his friends in Europe, if desired, with the intention that it should otherwise be permanently entombed at Mount Auburn, and that a monument should be erected over it at the public expense. The following works of doctor Spurzheim have been republished in Boston: Phrenology, or the Doctrine of the Mental Phenomena (2 vols.); Outlines of Phrenology; Elementary Principles of Education; and Philosophical Catechism of the Natural Laws of Man. From doctor Follen's Funeral Oration (published in Boston, in 1832) we extract the following additional notices of doctor Spurzheim's life:-He was the son of a farmer, and received his classical education at the college of Treves, being destined, by his friends, for the profession of theology. In consequence of the war, in 1795, the students of that college were dispersed, and Spurzheim went to Vienna. Here he devoted himself to the study of medicine, and became the pupil, and afterwards the associate, of doctor Gall, who was at that time established as a physician at Vienna. (See our articles Gall, and Phrenology, in the body of the work.) It was here, in 1800, that Spurzheim first attended a private course which doctor Gall had repeated from time to time, during the four preceding years, in order to explain, to a select audience, his new theory of the organs and functions of the brain. The dissection of the brain itself still remained very imperfect until 1804, when Spurzheim became his associate, and undertook especially the anatomical department. From that time, in their public as well as in private demonstration of the brain, Spurzheim always made the dissections, and Gall explained them to the audience. The great interest excited by these lectures in Vienna, and throughout Germany, roused the fears of that inveterate enemy of all innovations, the government of Austria. An imperial decree, which prohibited all private lectures unless by special permission, silenced the two teachers, and induced them, in 1805, to quit Vienna. They travelled together through Germany, explaining and demonstrating their physiological discoveries in the principal universities and cities, particularly in Berlin, Dresden, Halle and Munich. Their anatomical demonstrations excited, every where, great interest and applause. The peculiar physiological doctrine on the organization of the brain being adapted to various innate qualities of the mind, found many opposers, but also some warm adherents, and gave rise to a great number of publications, in which the subject was discussed. In the year 1807, Gall and Spurzheim went to Paris, where they demonstrated their theory of the brain, in the presence of Cuvier, and before many other distinguished men. Cuvier, at first, expressed his approbation of the general features of the new doctrine, but, in a report to the institute on the subject, in 1808, spoke of it with less favor. In Paris, they published their great work on the Anatomy and Physiology of the Nervous System (1810), and continued to lecture and labor together till 1813, when Spurzheim went to England, and began to lecture in London. Mr. Abernethy acknowledged the superiority of his anatomical demonstration over the previous mode of dissecting the brain. After lecturing in several cities of England and Ireland, doctor Spurzheim went to Edinburgh, where he was particularly desirous of exhibiting his demonstrations and explaining his doctrines, in consequence of the appearance of an abusive article on phrenology, in the Edinburgh Review (June, 1815). During the three years which he spent in England, he published several of his works on phrenology, among which was one under the title of the Physiognomical System. In 1817, he returned to Paris, where he gave lectures on the anatomy, physiology and pathology of the brain, and also devoted himself to the practice of medicine; and, in 1821, became doctor of medicine of the university of Paris. In 1825, he again visited England, where he lectured to crowded audiences; and, in 1828, once more returned to Paris. There he again renewed his lectures; and he remained there till his visit to this country. STARS, FIXED. (See Fixed Stars.) STIRRUP. The ancients were not acquainted with the use of this convenient article of equestrian costume, the emperor Mauritius, who flourished towards the end of the sixth century, being the first writer who makes mention of it, in his Treatise on the Military Art. The Roman youth were accustomed to leap upon their horses sword or lance in hand. A jasper, explained by Winckelmann; a basso-rilievo, engraved by Roccheggiani; and the painting of a Greek vase, published in Millin's Recueil de Monumens, all exhibit warriors mounting on horseback by the help of a cramp-iron attached to the pike or lance. Distinguished persons and old men had servants to place them on their horses, and conquered sovereigns were often compelled to perform this office for their vanquishers. Caius Grac chus caused to be placed at certain distances along the high roads, after the example of the Greeks, large stones to assist the horsemen in mounting. STONE, John Hoskins, governor of Maryland, distinguished himself in the revolution. In early life, and at an early period of the war, he was first captain in the celebrated regiment of Smallwood. At the battles of Long Island, White Plains and Princeton, he behaved with great gallantry; and, at that of Germantown, he received a wound which disabled him for the residue of his life. But he still exerted himself in the service of his country, as a member of the executive council of Maryland, until 1794, when he was chosen governor, and remained so for three years (as long a time as was allowed by the constitution). He died at Annapolis, in 1804, leaving behind him the reputation of an honest and honorable man, an intrepid soldier, and a liberal, hospitable and friendly citizen. STRENGTH OF MATERIALS. [The following article is extracted from Arnott's Elements of Physics.] "Strength depends on the magnitude, form and position of bodies, as well as on the degree of cohesion in_the_material.”—Of similar bodies the largest is proportionally the weakest. Suppose two blocks of stone left projecting from a rock that has been hewn, of which blocks one is twice as long, and deep, and broad, as the other. The larger one will by no means support as much more weight at its end than the other, as it is larger; and for two reasons: 1. In the larger, each particle of the surface of attachment, in helping to bear the weight of the block itself, has to support by its cohesion twice as many particles beyond it, in the double extent of projection, as a particle has to support in the shorter block; and, 2. both the additional substance, and any thing appended at the outer extremity of the larger, are acting with a double lever advantage to break it, that is, to destroy the cohesion. Hence, if any such projection be carried out very far, it will break off or fall by its own weight alone. What is thus true of a block supported at one end, is equally true of a block supported at both ends, and, indeed, of all masses, however supported, and of whatever forms. That a large body, therefore, may have proportionate strength to a smaller, it must be made still thicker and more clumsy than it is made longer; and, beyond a certain limit, no proportions whatever will keep it together, in opposion merely to the force of its own weight. This great truth limits the size and modifies the shape of most productions of nsture and of art,—of hills, trees, animals, architectural or mechanical structures,&c. Hills. Very strong or cohesive material may form bills of sublime elevation, with very projecting cliffs and very lofty perpendicular precipices; and such are seen, accordingly, where the hard granite protrudes from the bowels of the earth, as in the Andes of America, the Alps of Erope, the Himalayas of Asia, and the Mountains of the Moon in Central Africa. But material of inferior strength exhibits more humble risings and more rounded surfaces. The gradation is so striking and constant from granite mountains down to those of chalk, or gravel, or sand. that the geologist can generally tell the substance of which a hill is composed by the peculiarities of its shape. Even in granite itself, which is the strongest of rocks, there is a limit to height and projection; and, if an instance of either, much more remarkable than now remains on earth, were by any chance to be produced again, the law which we are considering would prune the monstrosity. The grotesque figures of rocks and mountains seen in the paintings of the Chinese, or actually formed in miniature for their gardens, to express their notions of perfect sublimity and beauty, are caricatures of nature, for which originals can never have existed. Some of the smaller islands in the Eastern ocean, however, and some of the mountains of the chains seen in the voyage towards China, along the coasts of Borneo and Palawan, exhibit, perhaps, the very limits of possibility in singular shapes. In the moon, where the weight or gravity of bodies is less than on the earth, on account of her smaller size. mountains might be many times higher than on the earth; and observation proves that the lunar mountains are much higher than ours. By the action of winds, rains, currents and frost upon the mineral masses around us, there is unceasingly going or an undermining and wasting of supports, so that every now and then immense rocks, or almost hills, are torn by gravity from the station which they have held siner the earth received its present form, and fall in obedience to the law now explained. The size of vegetables, of course, is obedient to the same law. We have no trees reaching a height of 300 feet, even when perfectly perpendicular, and sheltered in forests that have been unmolested from the beginning of time; and oblique or horizontal branches are kept within very narrow limits by the great strength required to support them. The truth that, to have proper strength, the breadth or diameter in bodies must increase more quickly than the length, is well illustrated by the contrast existing between the delicate and slender proportions of a young oak or elm, while yet in the seedsman's nursery, and its sturdy form when it has braved for centuries all the winds of heaven, and has become the monarch of the park or forest. Animals furnish other interesting illustrations of this law. How massive and clumsy are the limbs of the elephant, the rhinoceros, the heavy ox, compared with the slender forms of the stag, antelope and greyhound! And an animal much larger than the elephant would fall to pieces from its own weight alone, unless its bones were made of much stronger materials. Many have questioned whether the mammoth, or antediluvian elephant, could have lived on dry land, or must have been amphibious, that its great body might generally be borne up by water. The whale is the largest of animals, but feels not its mighty weight because lying constantly in the liquid support of the ocean. A cat may fall with impunity where an elephant or ox would be dashed to pieces. The giants of the heathen my thology could not have existed upon this earth, for the reason which we are now considering; although on our moon, where, as already stated, weight is much less, such beings might be. In the planet Jupiter, again, which is many times larger than the earth, an ordinary man from hence would be carrying, in the simple weight of his body, a load sufficient to crush the limbs which supported him. The phrase a little compact man, points to the fact that such a one is stronger in proportion to his size than a taller man. The same law limits the height and breadth of architectural structures. In the houses of fourteen stories, which formerly stood under the castle of Edinburgh, there was danger of the superincumbent wall crushing the foundation. Roofs. Westminster hall approaches the limit of width that is possible without very inconvenient proportions or central supports; and the domes of the churches of St. Peter, in Rome, and St. Paul, in London, are in the same predicament. Arches of a Bridge. A stone arch much larger than those of the magnificent bridges in London, would be in danger of crushing and splintering its material. Ships. The ribs or timbers of a boat have scarcely a hundredth part of the bulk of the timbers of a ship ten times as long as the boat. A ship's yard of ninety feet contains, perhaps, twenty times as much wood as a yard of thirty feet, and, even then, is not so strong in proportion. If ten men may do the work of a three-hundred-ton ship, many more than three times that number will be required to manage a ship three times as large. Very large ships, such as the two built in Canada in the year 1825, which carried each nearly 10,000 tons, are weak from their size alone; and the loss of these two first specimens of gigantic magnitude will not encourage the building of others like them. The degree in which the strength of structures is dependent on the form and position of their parts, will be illustrated by considering the two cases of longitudinal and transverse compression; and the rule for giving strength will be found to be, to cause the force tending to destroy, to act, as equally as may be, on the whole resisting mass, at the same time, and with as little mechanical advantage as possible. In longitudinal compression, as produced by a body on the top of a pillar, the weight, while the support remains straight, can only destroy the support by crushing it in opposition to the repulsion and impenetrability of all its atoms. Hence a very small pillar, if kept perfectly straight, supports a very great weight; but a pillar originally crooked, or beginning to bend, resists with only part of its strength; for the whole weight above is supported on the atoms of the concave side only, which are therefore in greater danger of being overpressed and crushed, while those on the convex side, separated from their natural helpmates, are in the opposite danger of being torn asunder. The atoms near the centre, in such a case, are almost neutral, and might be absent without the strength of the pillar being much lessened. Long pillars or supports are weaker than short ones, because they are more easily bent; and they are more easily bent because a very inconsiderable, and therefore easily effected, yielding between each two of many atoms, makes a considerable bend in the whole; while in a very short pillar, there can be no bending without a great change in the relatior of proximate atoms, and such as can be effected only by great force. The weight or force bending any pillar may be considered as acting at the end of a long lever, reaching from the end of the pillar to its centre, against the strength resisting at a short lever from the side to the centre. The strength, therefore, has relation to the difference between these. Shortness, then, or any stay or projection at the side of the pillar, which, by making the resisting lever longer, opposes bending, really increases the strength of a pillar. A column with ridges projecting from it is, on this account, stronger than one that is perfectly smooth. A hollow tube of metal is stronger than the same quantity of metal in a solid rod, because its substance, standing farther from the centre, resists with a longer lever. Hence pillars of castiron are generally made hollow, that they may have strength with as little metal as possible. In the most perfect weighing beams for delicate purposes, that there may be the least possible weight with the required strength, the arms, instead of being of solid metal, are hollow cones, in which the metal is not much thicker than writing paper. Masts and yards for ships have been made hollow, in accordance with the same principle. In nature's works, we have to admire numerous illustrations of the same class. The stems of many vegetables, instead of being round externally, are ribbed or angular and fluted, that they may have strength to resist bending. They are hollow, also, as in cornstalks, the elder, the bamboo of tropical climates, &c., thereby combining lightness with their strength. A person who visits the countries where the bamboo grows, cannot but admire the almost endless uses to which its straightness, lightness and hollowness, make it applicable among the inhabitants. Being found of all sizes, it has merely to be cut into pieces of the lengths required for any purpose; and nature has already been the turner, and the polisher, and the borer, &c. In many of the Eastern islands, bamboo is the chief material of the ordinary dwellings, and of the furniture, the fanciful chairs, couches, beds, &c. Flutes and other wind instruments there are merely pieces of the reed, with holes bored at the requisite distances. Conduits for water are pipes of bamboo; bottles and casks for preserving liquids are single joints of larger bamboo, with their partitions remaining; and bamboo, split into threads, is twisted into rope, &c. From the animal kingdom, also, we have illustrations of our present subject-the hollow stiffness of the quills of birds; the hollow bones of birds; the bones of animals generally, strong and hard, and often angular externally, with light cellular texture n, &c.-Transverse Pressure. When a horizontal beam is supported at its extremities, its weight bends it down more or less in the middle, the particles on the upper side being compressed, while the parts below are distended; and the bending and tendency to break are greater, according as the beam is longer and its thickness or depth is less. The danger of breaking, in a beam so situated, is judged of, by considering the destroying force as acting by the long lever reaching from the end of the beam to the centre, and the resisting force or strength as acting only by the short lever from the side to the centre, while only a little of the substance of the beam on the under side is allowed to resist at all. This last circumstance is so remarkable, that the scratch of a pin on the under side of a plank resting as here supposed, will sometimes suffice to begin the fracture. Because the resisting lever is small in proportion as the beam is thinner, a plank bends and breaks more readily than a beam, and a beam resting on its edge bears a greater weight than if resting on its side. Where a single beam cannot be found deep enough to have the strength required in any particular case-as for supporting the roof of a house-several beams are joined together, and in a great variety of ways, as is seen in house-rafters, &c., which, although consisting of three or more pieces, may be considered as one very broad beam, with those parts cut out which do not contribute much to the strength.-The arched form bears transverse pressure so admirably, because, by means of it, the force that would destroy, is made to compress all the atoms or parts at once, and nearly in the same degree. The atoms on the under side of an arch, resting against immovable abutments, must be compressed about as much as those on the upper side, and cannot therefore be torn or overcome separately. The whole substance of the arch, therefore, resists, almost like that of a straight pillar under a weight, and is nearly as strong. To be able to adapt the curve to the size of an arch, and to the nature of the material, requires in the architect a perfect acquaintance with measures, &c. An error which has been frequently committed by bridge-builders is, the neglecting to consider sufficiently the effect of the horizontal thrust of the arch on its piers. Each arch is an engine of oblique force, pushing the pier away from it. In some instances, one arch of a bridge falling, has allowed the adjoining piers to be pushed down towards it, by the thrust, no longer balanced, of the arches beyond, and the |
