GINSENG, in botany. See PANAX. GIRDERS, in architecture, some of the largest pieces of timber in a floor. Their ends are usually fastened into summers and breast-summers, and joists are framed in at one end to the girders. The size of girders and summers, upon the rebuilding of London, were ordained by act of Parliament, to be in length from ten to twenty-six feet, in breadth from eleven to seventeen inches, and in depth from eight to fourteen inches. It was also ordained by the same statute, that no girder or summer should be less than ten inches in the wall, and that their ends should be laid in loam; as also that they be of good hearty oak, as free from knots as may be, because that will be the least subject to breaking, and may with more safety be relied on in this cross and transverse work.

GIRT, in the measuring of timber, is the circumference of a tree, though some use this word for the fourth part of the circumference only, on account of the use made of it. The square of the fourth part is considered as equal to the area of the section of the tree, which square therefore multiplied by the length of the tree is accounted the solid content. This content is about one fourth less than the true quantity, being nearly equal to what it will be after the tree is hewn square, and is probably intended to make an allowance for the squaring the tree.

GIRT, in naval affairs, the situation of a ship which is moored so tight by her cables as to be prevented turning to any change of the wind or tide, to the current of which her head would otherwise be directed. The cables, to produce this, are extended by a strong application of mechanical powers within the ship, so that as she veers, or endeavours to swing about, her side bears upon one of the cables, which interrupts her in the act of traversing.

GIRTH line, a rope passing through a single block on the head of the lower masts to hoist up the rigging, and the persons employed to place the rigging and cross trees on the mast heads. The girth-line is the first rope employed to rig a ship, after which it is removed till the ship is to be unrigged.

GISEKIA, in botany, so named in honour of Paulus Dietericus Giseke, a genus of the Pentandria Pentagynia class and or

tulaceæ, Jussieu. Essential character: calyx five-leaved; corolla none; capsule five, approximating, roundish, one-seeded. There is but one species, viz. G. pharnacioides, trailing Gisekia, an annual plant, and a native of the East Indies.

GIVEN, among mathematicians and philosophers, the same with data. If a magnitude be known, or we can find another equal to it, it is said to be given in magnitude. Or when the position of any thing is known, it is said to be given in position : when the diameter or radius of a circle is known, the circle is given in magnitude. The circle is given in position, when the position of the centre is given. See Data.

GLABRARIA, in botany, a genus of the Polyadelphia Polyandria class and order. Essential character: calyx five-cleft; petals five; nectary composed of bristles the length of the calyx; stamens thirty, always in sixes; pericarpium a drupe, There is but one species, viz. G. tersa, a large tree resembling the camphor tree, the wood of which is very light and pale coloured, and not being liable to rot or to be injured by insects, it is much used for building both houses and ships. It is a native of the East Indies.

GLACIERS. Those vast piles of eter nal ice with which it has pleased the author of nature to crown the immense chasms between the summits of the Alps, objects more grand, sublime, and terrific, than are any others of the phenomena of nature which remain stationary. These tremendous spires and towers of uncertain and brittle fabric, seem to forbid the attempts of travellers to explore the depth between them, or even the rocks and rich vallies around them; but courage and perseverance have been attended with commensurate success, and we are enabled by their labours to learn preyiously concealed wonders, and to reason upon the causes which produced them. In treating on this subject, it must be remembered, with satisfaction, that great part of our information is derived from the exertions of our own countrymen, ever distinguished for patient investigation and intrepid exploration.

M. Bourrit, Precentor of the Cathedral Church at Geneva, mentions in the relation of his journey to the glaciers of Savoy, the enterprise of Messrs. Windham and Pocock, in 1741, who inspired by the artless relations of the peasants, descriptive of the

sublimity of their country, when they descended with honey and chrystals for sale, determined to visit those frightful regions of ice which had received the appellation of Les Montagnes Maudites, or the accursed mountains; the gentlemen alluded to took every precaution for securing their safety; but entertaining many well-grounded fears, naturally arising from a first attempt, they did not reach any considerable distance beyond the edge of the ice in the valley of Montanvert, yet their example operated so powerfully as to induce several others to imitate them, and proceed to the boundary whence they returned; at length M. de Saussure had the resolution and courage to penetrate across the ice to the very extremities of the vallies; Mr. Coxe followed soon after and every possible information may be obtained from their publications which the nature of the subject will permit.

The most astonishing phenomenon attending the glaciers, is their near approach to the usual vegetation of summer, for what can be more wonderful than to view wheat ready for the sickle, parched brown by the rays of the sun, separated only by the intervention of a few feet from the chilling influence of an endless bed of ice, which seems impenetrable to its rays.

Many systems and theories have been ingeniously suggested to ascertain the first cause of the glaciers, their maintenance, and whether they increase or diminish in extent, of which Gruner's, improved and illustrated with actual observation by M. de Saussure, is the most rational and probable, and Mr. Coxe implicitly adopts it. Admitting that a person could be raised sufficiently above the summits of the Alps of Switzerland, Savoy, and Dauphine, to comprehend the whole at one view, he would observe a vast chaos of mountains and vallies, with several parallel chains, the highest of which are situated in the centre, and the remainder gradually lessening as they retire from it. The central chain he would find to-be surmounted by stupendous fragments of rock, towering in rude masses, which bear vast accumulations of snow and ice where they are not decidedly perpendicular, or do not overhang their bases; on each side he would see the intervening chasms and gulphs, filled with ice, descending thence even into the verdant vallies rich with foliage and cultivation. The inferior ranges of mountains, next the central, present the same appearance in a lesser degree,

but in those more remote the snow and ice is confined to the most elevated points; and others, still further removed, are covered with grass and plants, which, in their turn, give place to the hills and vallies common in any part of the world.

Mr. Coxe divides the glaciers in the above general survey into two classes, the first occupy the deep vallies situated in the bosom of the Alps, and the second adhere to the sides and summits of the mountains. Those in the vallies are far more extensive than the upper glaciers, some are several leagues in length, and that of Des Bois is three miles broad and fifteen long; but they do not communicate with each other, and there are few parallel to the central chain; their upper extremities are connected with inaccessible precipices, and the lower proceed as already mentioned, quite into the vales; the depth of these astonishing accumulations of frozen fluid vary from 80 to 600 feet, and they generally rest on an inclined plane; urged forward by their own enormous weight, and but weakly supported by the pointed rocks inserted in their bases, they are universally intersected by yawning chasms of dreadful aspect to the curious investigator, who beholds fanciful representations of walls, towers, and pyramids, on every side of him; but upon reaching those parts were the glacier rests upon an horizontal plane, his progress is seldom impeded by considerable fissures, and he walks in safety over a surface nearly uniform, and not so perfectly polished as that of ponds and rivers suddenly and violently frozen. The absence of transparency, the various marks of air bubbles, and the general roughness, so perfectly rescmble the congelation of snow, when half. restored to fluidity, that M. de Saussure was immediately led to form the following probable theory of the formation of the glaciers.

Snow is constantly accumulating in the recesses or depths of the mountains, during nine months of the year, by the usual fall of moisture, and the descent of vast masses borne down by their weight from the precipices and crags above. Part of this is necessarily reduced to water by slight thaws and casual rains, and being frozen in this state the glacier is composed of a porous opaque ice.

The upper glaciers, Mr. Coxe subdivides into those which cover the summits, and those which extend along the sides of the Alps; the former originate from the snow

frequently falling and congealing into a firm body, though not becoming actual ice, which the brilliancy of the projections has induced some philosophers to suppose it. M. de Saussure having explored Mont Blanc, ascertained that the top was encrusted with ice, which might be penetrated by a stick, covering a mass of snow on the declivities, so chilled and dry as to be incapable of coherence.

The sides of the Alps support a congelation of half dissolved snow, which is different from the pure snow of the summits and the ice of the lower glaciers. Two causes operate to produce this effect, the first is the descent of water from the higher regions, where a dissolution of the snow sometimes occurs; and the second arises from the more favourable situation of these parts for reflecting the rays of the sun and the consequent melting of the snow. From hence downwards the ice adhering to the cavities becomes gradually more solid by the freezing of the snow-water, then nearly divested of that air which in the less dissolved portions renders the ice, formed from it, porous, opaque, and full of bubbles.

Considerable difference of opinion has prevailed amongst philosophers, whether the masses of ice and snow in these regions of endless winter increase, decrease, or remain nearly stationary; Mr. Coxe seems inclined to think they vary in their size, that gentlemen observes, that the glacier of Montanvert is generally bordered with trees; near the base of this vast body of frozen matter the ice is excavated into an arch, perhaps one hundred feet in height, whence the Arveron rushes with impetuosity and in a large sheet of water. As he approached the ice he passed through a forest of firs, those near the arch were very ancient and about eighty feet high, the trees between them and the glacier were evidently younger from the inferiority of their size and other intrinsic marks, others still less, had been enveloped by the ice, and many were thrown down; arguing from this gradation in the appearance of the firs, he concludes, that the glacier has originally extended to the full grown ancient trees, and dissolving, young ones have grown on its former site, which have been overturned by a fresh increase of ice.

This inference seems almost conclusive, but it is still further supported by the fall of large pieces of granite called moraine by the inhabitants, which, borne along by the

ice, sink through it as it dissolves, and falling into the plain, form a border along its extremity; those have been urged forward by the pressure of new ice, and extend even to the place occupied by the large firs.

Exclusive of these circumstances, Mr. Coxe discovered, that the glacier of Grindelwald had diminished, at least, 400 paces between the dates of his two visits in 1776 and 1785; and in the valley of Chamouny, the Muraille de Glace, which he had described as forming the border of the glacier of Bosson, in 1776, no longer existed in 1785, and young trees had grown on the site of the edge of the glacier of Montanvert.

In opposition to the evidence thus adduced, it is argued that the operations observable in the vallies arising from the concentration of solar heat, form no data for judging of those on more elevated situations, where it is asserted a greater quantity of snow falls and becomes ice than can possibly be dissolved annually, and experience proves, beyond doubt, that mountains have been covered, passages obstructed, pastures and habitations destroyed by the ice within the memory of man. In replying to these arguments the result obtained is extremely satisfactory. The rain and sleet falling during summer not only thaws the ice and snow, but forms various channels in it, the water descending must wear and carry along part of the frozen sides and depths, and prepare the way for separating and throwing down large masses of each, which are termed avalanches in some parts of the country, and lauwine in others; those tremendous bodies accumulating by adhesion in their progress, overwhelm every thing in their way, and rush to the vallies from the highest summits, whence various other causes serve to detach them. Here the traveller often meets a dreadful and instantaneous fate; but humanity has endeavoured to obviate it as far as human abilities will permit. Matthison, who visited the monastery of St. Bernard, founded for the relief of those who cross the Alps, speaks thus of the lauwine or avalanche, and the excellent canons of St. Bernard: "In the very worst seasons, as often as it snows, or the weather is foggy, some of these benevolent persons go forth with long poles, and, guided by their excellent dogs, seek the highway, which these sagacious animals never miss, how difficult soever to find. If then the wretched traveller has sunk

beneath the force of the falling lauwine, or is immersed in the snow in a benumbing swoon, how deeply soever he may be buried, the dogs never fail of finding the place of his interment, which they point out by scratching and snuffling, when the sufferer is dug out and carried to the monastery, were every possible exertion is used for his restoration. The number of those who lose their lives in the field of battle is known to all Europe, but no one could give me an account what number have thus had the gift of life conferred on them a second time. Yet notwithstanding all the care and attention of these real friends of mankind, and their faithful dogs, scarcely a year passes, but as the snow melts away in summer, the dead bodies of travellers are discovered, who remote from their homes, and all that was dear to them, have perished here unnoticed and unknown. As the ground for a considerable extent round the monastery is solid rock, the dead bodies are collected together in a chapel, lying on its eastern side, which is made to admit a thorough draft of air, by openings in the walls, guarded by large iron bars. The sight of so many unfortunate persons, probably collected from various parts of the world, yet howsoever remote from each other in life, brought hither by an unfortunate similarity of fate to rest together in death, afflicted my inmost soul. They are all covered with palls, and as in this frozen region no exanimate body moulders, but only gradually shrivels and dries away, so the features remain undisfigured for a considerable length of time, and some have even been recognized by friends and relations, after having lain here for two or three years. The bodies are not disposed one over the other, but are all placed upright, and each fresh corpse leans its head on the breast of the former; this disposition has something familiar in it, and gives them the semblance of being united only in a general slumber. Four rows of these slumberers already rest here, from the faces and han.ls of many of whom the palls have slipped off and left them uncovered: these have all a, perfect mummy-like appearance." The fall of the avalanche necessarily reduces the quantity of snow and frozen fluid on the summits, and the transfer of it to a warmer region, must facilitate its dissolution. The lower glaciers, though not subject to equally precipitate descent, cannot otherwise than gradually advance towards the vallies, which may be inferred from the

constant passage of torrents under them, and their own enormous weight; besides the chasms that universally intersect them, plainly evince that their foundations being partially undermined, they glide slowly downward overturning trees, and pushing stones before them; the edges obtruded on the earth by this means naturally dissolve far more rapidly than if they remained stationary.

Another means of dissolution arises from evaporation, which takes place on every portion of the globe, however elevated. Exclusive of the above causes, are the constant play of the beams of the sun on the surfaces of the glaciers, which being capable of redoubled heat by concentration and refraction in some favourable positions, must produce very violent thaws; the air heated by this and similar means in other parts of the mountains, often meets the traveller in streams, which seem as if proceeding from a hot bath, consequently those projections subject to their influence, must vanish rapidly; but a more certain and regular change occurs from the mean temperature of the earth, where the transition from summer heats to winter colds cannot ever take place. "This mean temperature," says Mr. Coxe, termed by some philosophers the internal heat of the earth, is always above the freezing point, as is evi dent from the heat of the springs which issue from the bowels of the earth. In winter, therefore, or in those high regions of the globe, where the cold is usually be low the freezing point, when any spot of ground is covered with only a thin coat of snow, it may be so far cooled, to a certain depth, by the influence of the external air, as not to be capable of dissolving any part of the superincumbent snow. But when the mass of snow is of such a thickness as to protect the surface of the ground from the effects of the atmospherical cold, the mean temperature which is always above the freezing point will be sufficient to melt the contiguous surface of snow, and to occasion a constant thaw, which supplies those currents of water that flow at all seasons from the upper and lower glaciers."

Having endeavoured to explain the causes of the glaciers and their changes, it will be proper to give an idea of their sublimity in the words of M. Bourrit, who appears to have viewed and described them with all that enthusiasm which such splendid objects must have inspired. "To come at this collected mass of ice (Des Bois) we crossed

the Arve, and travelling in a tolerable road, passed some villages or hamlets, whose inhabitants behaved with much politeness; they invited us to go in and rest ourselves, apologized for our reception, and offered us a taste of their honey. After amusing ourselves some time amongst them, we resumed our road, and entered a beautiful wood of lofty firs, inhabited by squirrels. The bottom is a fine sand, left there by the inundations of the Arveron; it is a very agreeable walk, and exhibits some extraordinary appearances. In proportion as we advanced into this wood, we observed the objects gradually to vanish from our sight; surprised at this circumstance, we were earnest to discover the cause, and our eyes sought in vain for satisfaction, till having passed through it, the charm ceased. Judge of our astonishment, when we saw before us an enormous mass of ice, twenty times as large as the front of our cathedral of St. Peter, and so constructed, that we have only to change our situation to make it resemble whatever we please. It is a magnificent palace, cased over with the purest crystal; a majestic temple, ornamented with a portico, and columns of several shapes and colours; it has the appear- ̧ ance of a fortress, flanked with towers and bastions to the right and left, and at bottom is a grotto, terminating in a dome of bold construction. This fairy dwelling, this enchanted residence or cave of fancy, is the source of the Arveron, and of the gold

which is found in the Arve. And if we

add to all this rich variety, the ringing tinkling sound of water dropping from its sides, with the glittering refraction of the solar rays, whilst tints of the most lively green, or blue, or yellow, or violet, have the effect of different compartments, in the several divisions of the grotto, the whole is so theatrically splendid, so completely picturesque, so beyond imagination great and beautiful, that I can hardly believe the art of man has ever yet produced, nor ever will produce a building so grand in its construction, or so varied in its ornaments. Desirous of surveying every side of this mass, we crossed the river about four hun dred yards from its source, and mounting upon the rocks and ice, approached the vault; but while we were attentively em. ployed in viewing all its parts, astonished at the sportiveness of fancy, we cast our eyes at one considerable member of the pile above us, which was unaccountably supported; it seemed to hold by almost

nothing: our imprudence was too evident, and we hastened to retreat; yet scarcely had we stepped back thirty paces before it broke off all at once with a prodigious noise, and tumbled, rolling to the very spot where we were standing just before."

GLACIS, in fortification, that mass of earth which serves as a parapet to the covered way, sloping easily towards the champaign, or field. The glacis, otherwise called esplanade, is about six feet high, and loses itself by an insensible diminution in the space of ten fathoms.

GLADIATORS, persons who fought for the amusement of the public in the arenas of amphitheatres in the city of Rome, and at other places under the dominion of the Romans. The term is derived from their use of the gladius, or sword; and the ori. gin of this horrid custom is said to have been the practice of sacrificing captives to the manes of chiefs killed in battle. It seems, however, more probable, that it arose from the funeral games of antiquity, when the friends of the deceased fought in honour of his memory; an instance of which occurs in the twenty-third book of the Iliad, at the burning of the body of Patroclus, Achilles having ordained every solemn rite usual upon those occasions, Homer adds,

"The prizes next are ordered to the field, For the bold champions who the castus wield."

The leather which composed the cæstus be

ants to give each other mortal blows, though ing loaded with lead, enabled the combatthe hands only were used. Epeus, of giGrecian chiefs, who were terrified at his gantic stature, challenged the whole of the bulk, and Euryalus alone accepted his defiance:

"Him great Tydides urges to contend, Warm with the hopes of conquest for his friend;

Officious with the cincture girds him round,

And to his wrist the gloves of death are bound."

The captives slain on this occasion were not commanded to fight; they had been led to the pile, and died with the sheep, oxen, coursers, and dogs, that their bodies might be burnt by the flames which consumed that of Patroclus:

"Then, last of all, and horrible to tell, Sad sacrifice! twelve Trojan captives fell."