could not find room on the benches.

The section shows that the radiating flights of steps intercepting the benches do not run through their whole extent, but are themselves intercepted and taken up again, other lines or flights commencing intermediately and at intermediate heights. Access is given to these flights at their upper ends by doorways from the corridors behind, sometimes directly, and sometimes by means of the internal staircases; and in most cases a short reversed flight of steps is made on the outside of the doorways, or vomitories, as they are termed, to afford headway, and avoid intercepting the benches further back than could be possibly helped. Almost every thing that appears in the section above the level of the third story, except the external wall itself, is restored from analogy and conjecture. The peristyle, or encircling range of columns before the upper gallery, is entirely from conjecture; but for the galleries themselves there is sufficient evidence in the existing indications of stairs, and in the toothings of the remaining walls and piers. The benches in the grand series were probably of stone, perhaps of marble; but in the galleries it is most likely they were of wood, and graduated so as to give their occupiers a view of the arena.

The most distinguished seats were those on the podium, and these were assigned to the emperor, whose place was, by way of eminence, called the suggestum, and to the senators, to foreign ambassadors, and to the great officers of the state. The magistrates appear to have sat here in their curule chairs: and the person who gave the games seems to have occupied a sort of pulpit on the podium, called the editoris tribunal. The cunei, or wedges, behind and above, were assigned to different classes, according to their rank, station, and tribe. The Vestal virgins had one of the best positions assigned to them, and with them sat uch ladies of high rank as could obtain the advantage; but the women generally occupied the open gallery at the top.

As the plan indicates, the four central entrances those which lie on the ends of the diameters of the ellipsis-are wider than the corresponding parts of the rest of the structure. They were arcaded through, and finished more carefully, especially those leading from the sides, or on the minor axis; these, it is most likely, were reserved for those persons who went to the seats on the podium, and as they gave access also to the arena, they would of necessity be more strictly guarded. It does not appear that any part of the structure above the level of the ground, and outside of the arena, was appropriated as dens for the beasts which were used in the shows; for indeed the corridor leading to the principal seats in the amphitheatre must have been traversed by them in their way to the arena, if that were the case. Substructions were discovered and excavated a few years ago over the whole extent of the arena; these lead to a belief that it was floored with wood, so that the animals required for the day may have been kept in dens under the floor, and allowed to issue at traps in it. But some have supposed dens ranged all round the arena, within its surface and below the podium, from which the beasts would issue to the combat directly. In the Colosseum the great crowning cornice of the external elevation is pierced through at regular intervals with square holes or mortises, from which grooves are cut down through the rest of the entablature flush with the outer surface of the wall; and every mortise and groove is immediately above a strong projecting stone or corbel at about two-thirds the height of the pilastraded ordinance. These are supposed to have been used to insert and receive poles to carry an awning strained over the whole inclosure to protect the spectators from the sun and from rain. It is however difficult to understand how such an extent of cloth or canvass could have been borne in that manner without some intermediate support, of which we are not aware.

The external elevation is composed, as it has been already described, and as the elevation indicates, of three series or stories of attached or engaged columns with their usual accesssories, and a pilastraded ordinance, forming a species of attic, which is pierced with windows, -one in every other interspace. The lowest ordinance of columns rests on the upper step of the substructions, or on the ground floor of the structure; it is of what is termed the Doric style or order, but in the debased Roman manner, and its entablature wants the distinguishing feature of that style, the triglyph. The intervening arches are semicircular; they spring from moulded imposts, and have moulded archivolts on their outer faces. The second ordinance is in the Roman Ionic style, having voluted capitals to the columns; and the third is in the Corinthian or foliated style: these, as before stated, rest upon continued, but broken or recessed, stylobata, but their entablatures are, like the rest, perfectly unbroken throughout, and the arches in the intercolumniations in both, correspond exactly-except in minor details-with those of the lowest or Doric ordinance. The pilasters have foliated capitals also, and are called composite; they rest on deep plinths under which there is a continued and recessed dado superimposing the Corinthian entablature;-this dado is pierced with holes or small windows, alternating with those of the ordinance above, to give light to the corridor behind the lower and under the upper gallery on the inside. The crowning entablature is made bold and effective by deep modillion blocks or consoles occupying the whole depth of the froze.

The style of ese architectural decorations is, for the most part, rude and tasteless; the Colosseum, however, from its magnitude, from its general form, and nɔ doubt also from the feelings arising from the contrast between its present state and ancient splendour, never fails to

produce a profound impression on the spectator. Internally the amphitheatre must always have been strikingly grand and impressive; here none of the littlenesses of storied columns appeared, but the long unbroken lines of the podium, and the graduated series of the benches, and the galleries with the encircling peristyle above-when it existed -would have been as beautiful in general effect, as anything architecture ever produced.

There are varieties in the arrangement of the details of the amphitheatre, as other examples show. Intermediate concentric galleries, platforms, or precinctions sometimes intercepted the great bank of graduated benches to serve as passages of communication; and sometimes each staircase communicated directly and exclusively with one vomitory, instead of leading to encircling corridors which communicated generally, and gave access alike to every part of the enclosure.

Next in importance to the Colosseum at Rome, of existing structures of the kind, is the Ampitheatre of Verona. The prefixed vignette will give a tolerable idea of its state of preservation. The great external cincture is entirely gone, with the exception of four arches and their accessories; but the great bank of concentric benches, with the staircases leading to them, and the parts about the arena, remain in a comparatively perfect state. The outer cincture was pierced with seventy-two arches, which number appears in the inner, with the corresponding radiating walls to the traversing passages and staircases, -for this had not a second encircling corridor on the outside of the stairs block as the Colosseum has. The outer dimensions of this structure were 502 feet by 401 feet; the length of its arena is 242 feet, and its breadth or length, on the conjugate, 146 feet; the form, of course, was ellipitical.

The amphitheatre at Nimes in Languedoc is large (430 feet by 378), and in comparatively good preservation. The great external cincture of an amphitheatre (436 feet by 346) remains in a very perfect state at Pola in Istria. Rome contains the remains of a second amphitheatre called the Castrensian. There are also considerable remains of an amphitheatre at Capua, rivalling in size that at Verona; and of another at Pozzuoli near Naples. That of Pompeii, it has been already remarked, was an extensive structure. It was also in many respects peculiar, but it is not so well preserved as some other examples which have been more exposed, as it suffered considerably from earthquakes before it was buried. At Pæstum, there are indications of an amphitheatre, though not a large one; at Catania, in Sicily, the upper and outer encircling corridor of an extensive amphitheatre is accessible, considerably under the level of the modern city, buried by the torrents of lava from Mount Etna. Syracuse and several other of the ancient cities of Sicily exhibit remains or indications of small amphitheatres. In our own country, as has been noticed, there are several vestiges of amphitheatres; indeed, wherever Roman remains are found to any extent, whether at home or abroad, some indication may be almost certainly discovered of the existence at some time of an amphitheatre. AMPHITRITE, is represented by Hesiod as a goddess, the wife of Poseidon or Neptune, to whom she bore three sons; and she changed Scylla into a horrible monster when she had become jealous of her. By later poets she is treated as the goddess of ocean generally. There was a temple to Neptune and Amphitrite at Tenos, as is shown by an inscription on one of the marbles of the Elgin collection in the British Museum; and in the temple of Poseidon on the Corinthian Isthmus, there was a statue of the goddess. Amphitrite was represented in Greek art as resembling Aphrodite, but her hair was confined by a net. There is a colossal statue of her in the Villa Albani at Rome. She is also frequently represented on coins, especially on those of Syracuse. AMPHITRITE. One of the group of small planets revolving between Mars and Jupiter. [ASTEROIDS.]

A'MPHORA (aupopeús), in its ordinary acceptation, means an earthen vessel, used as a measure for liquids both by the Greeks and Romans, and for preserving wine, grapes, olives, oil, and other articles which required careful keeping. It received its name on account of its two ears or handles. It is generally two feet, or two feet and a half in height : and the body, which is usually about six inches in diameter, ending upwards with a short neck, tapers toward the lower part almost to a point. This pointed end was inserted in a hole in the ground, or in a stand to keep the vessel upright. The Attic amphora contained three Roman urnæ, or seventy-two sextaries, equal to about two gallons five pints and a half of English wine-measure. The Roman, sometimes called the Italic amphora, contained two urnæ or forty-eight sextaries, about seven gallons one pint English. Homer mentions amphoræ both of gold and stone; in later times glass amphora were not uncommon; and the Egyptians had them of brass. There are various specimens of earthen amphora in the British Museum, in the Elgin and Townley Galleries.

There was another amphora among the Romans, which was a dry. measure, and contained about three bushels.

Earthen amphora of the Roman time have been frequently found in England. Like other domestic vessels of the Romans, they appear to have been sometimes used as funeral urns. They were also used as coffins the amphora was cut in half in the direction of its length, and the corpse having been placed inside, the two halves were united again and buried. Amphoræ used for wine were usually lined with pitch or some other coating, on account of the porous nature of the material of which they were formed. Amphora were placed as urinals

It must be measured towards the north or south points of the horizon, according as the declination is north or south. For the fixed stars, the amplitude remains the same throughout the year: but for the sun it varies with the declination, being nothing at the equinoxes, and about 34 points of the compass at the solstices, or more exactly 39° 44' of amplitude, in the latitude of London; that is, at the summer solstice, it rises between N.E. by E. and N.E., and sets between N.W. by W. and N.W.; and at the winter solstice, it rises between S.E. by E. and S.E., and sets between S. W. by W. and S. W. The term amplitude was also applied to what is more commonly called the range of a gun; that is, the whole horizontal distance which the gun will carry. It is sometimes also used in the integral calculus. AMPUTATION, from amputo, to cut off; the operation of cutting off a limb from the body. Such is the constitution of the animal body in general, and especially of the more perfectly organised body, that if one part of it be diseased, the whole system suffers, while a general disturbance of the system cannot exist long without producing specific disease in some individual organ. Hence constitutional and local diseases are found to exert a most important influence over each other. Some local diseases are of an incurable nature, and proceed progressively from bad to worse. At first, these diseases may not materially affect the general health, but in their progress they produce so much constitutional disturbance, as to endanger life, and ultimately to destroy it. In this case, life is really endangered and destroyed by the local malady; remove that, provided the removal can be effected before the general health is irreparably impaired, and not only is death averted, but health itself is restored. Hence, in all ages, the necessity and advantage have been obvious enough, of removing a part of the body for the sake of preserving the remainder, and men have always been willing to submit to the loss of a limb in order to save the body, on the ground" that it is better to live with three limbs than to die with four." But although it must always have been clear, that it is a gain to save life even at the cost of a limb, when nothing but the removal of the limb can preserve the body, yet it was not always easy to make the sacrifice. Whoever understands the circulation of the blood, and considers the quantity that is sent, and that must necessarily be sent, to each member of the body for its nourishment, and the magnitude of the blood-vessels that are divided in cutting off a limb, will readily perceive how impossible it must have been to perform the operation of amputation before any certain mode was known of stopping the flow of blood from the wounded blood-vessels. But no such mode of stopping hæmorrhage was known to the ancients: consequently, though they daily saw the necessity of performing the operation of amputation, yet they looked upon the operation with terror, and shrunk from the responsibility of undertaking it. And no wonder : when they did venture upon it, the consequences were appalling. They cut through the flesh with a red-hot knife, hoping by this means to prevent a fatal loss of blood. After having performed this operation, they dressed the wound with scalding oil, in order to complete what the burning knife may have left imperfect. But these expedients stopped only for a short time the flow of blood. The whole surface of the wound was converted into an eschar, which for a time stopped the bleeding. But the eschar being dead matter it was at length thrown off by the action of the living parts beneath. The moment this took place, the mouths of the blood-vessels were again opened, hæmorrhage took place just as at first, and the patient perished from loss of blood. The uniformity with which this event took place after amputation performed in this mode, could not but cause the operation to be regarded with dismay. Nevertheless, it is pretty clear, that in the time of Celsus, the surgeons of that age were not without some notion of the true mode of stopping hæmorrhage from wounded blood-vessels, for that writer gives particular directions to take hold of the vessels, to tie them in two places, and then to divide the intermediate portion; certain, however, it is, that this practice was not extended to amputation, because nothing was ever amputated by the ancients but a part absolutely mortified or dead; and in a part thus mortified or dead, it is not practicable to secure the blood-vessels by the needle and ligature. The general introduction into surgery, of the method of stopping hæmorrhage by taking up the divided blood-vessel with a needle, and placing a ligature around it, must, therefore, be considered as much a modern improvement, as if no allusion whatever had been made to it by ancient writers.

But if a knowledge of the mode of stopping hæmorrhage by tying the blood-vessel, be indispensable to the safety of surgical operations in general, the knowledge of some mode of preventing the loss of blood

during the actual performance of an operation is indispensable to the safety of the operation of amputation in particular. So large are the trunks of the main blood-vessels that supply the limbs, and so great is the quantity of blood that flows from them in a short space of time, that loss of life is always the consequence of a want of command over these great vessels. By the invention of the instrument termed the tourniquet, an invention of the 17th century [TOURNIQUET], this command is obtained. By these instruments, then, namely, the tourniquet, and the needle and ligature, modern surgeons have such a perfect command over the blood-vessels, that operations may be performed, in which the largest trunks are divided without the loss scarcely of a single drop of blood. On this account, the mere removal of a limb excites in the modern surgeon no degree of anxiety; the operation of amputation is scarcely ever attended with the slightest hazard; nevertheless, there are circumstances connected with amputation of the greatest possible importance, delicacy, and difficulty, on a clear and correct view of which life depends; to obtain such a view, the most extensive knowledge, and the most accurate discrimination, are requisite; while, to act in conformity with it, a high degree of moral courage is often no less necessary. Perhaps the determination of the exact time at which to amputate is sometimes among the most difficult points of surgery; that is, the determination of the time when the preservation of the limb is no longer possible; and when, therefore, it is right to put an immediate stop to any further exhaustion of the health and strength by the removal of the limb. The recent introduction of the use of anaesthetics, in order to produce a state of insensibility in those submitting to the operation of amputation, has been found to exercise a most beneficial effect on recoveries after amputation. [ANESTHETICS.]

AMULET, in barbarous Latin, Amuletum, or Amoletum. It comes from the Arabic Hamalet, a thing suspended. An amulet hung round the neck, or carried in any other way about the person, is absurdly believed to have the effect of warding off morbid infections and other dangers, and even of curing diseases by which the body has been already attacked. The belief in the efficacy of amulets has subsisted at some time among almost every people, and the thing has been denoted by a great variety of names, which it is unnecessary here to enumerate. The phylacteries, or bits of parchment with passages from the Bible written upon them, which the Jews were wont to carry about with them, were amulets; such were probably the ear-rings mentioned in Genesis xxxv. 4; and in Hosea ii. 13. Jerusalem is represented as decking herself with the ear-rings of Baalim. Of the same character as the Jewish phylacteries are the scraps of paper inscribed with sentences from the Koran, which the Moorish priests sell to the negroes of Africa, and to which the latter give the name of Fetishes. This superstition, which existed also among the Greeks and Romans, appears to have in early times prevailed extensively among the converts to Christianity, if we may judge by the denunciations directed against it by St. Chrysostom, and others of the fathers. But even down to our own day, it has continued to be an article of the popular creed, that certain medical preparations, and other things, merely carried about the person, have the power both of repelling and of healing diseases. Even the celebrated Robert Boyle adopts this notion, assuring us that he once experienced the efficacy of such an amulet in his own case. "Having been one summer," he says, "frequently subject to bleed at the nose, and reduced to employ several remedies to check that distemper; that which I found the most effectual to stanch the blood was some moss of a dead man's skull (sent for a present out of Ireland, where it is far less rare than in most other countries), though it did but touch my skin till the herb was a little warmed by it." ('Essay of the Porousness of Animal Bodies.' See also his Essays on the Usefulness of Natural Philosophy,' and his 'Experimental Discourse on some Unheeded Causes of the Insalubrity and Salubrity of the Air.') The anodyne necklace, which consists of beads formed from the roots of white bryony, and is sometimes hung around the necks of infants with the view of assisting their teething, is an instance of the still surviving confidence in the medical virtue of amulets. Such also is the belief generally entertained by seafaring people, that a child's caul on board their ship will preserve them from being lost-and many other examples might be easily quoted. Even in 1858, though probably without much superstitious belief, charms were advertised set as jewels, and among them were pieces of the Atlantic cable. AMYGDALIC ACID. (CH2801). Produced by the action of alkalies upon amygdalin.

Liebig and Wöhler. It is met with in bitter almonds, the leaves of the cherry laurel, the kernels of peaches, and is probably also contained in all those parts of vegetables which yield hydrocyanic acid when distilled with water.

Amygdalin is prepared as follows:-Bitter almonds are strongly pressed between hot plates of iron, so as to expel the fixed oil they contain. The resulting mass is extracted with boiling alcohol of 90 or 95 per cent., and to the filtered and clarified alcoholic solution, evaporated to one-sixth its volume, is added half its bulk of ether, which precipitates the whole of the amygdalin. The precipitate is finally washed with ether and purified by recrystallisation from alcohol. Four pounds of bitter almonds yield about an ounce of amygdalin.

Amygdalin crystallises in white pearly plates, which are very slightly soluble in cold, but easily soluble in boiling absolute alcohol. It dissolves readily in water, but is insoluble in ether. Its aqueous solution possesses a slightly bitter taste. The most interesting property of amygdalin is, that when its solution is placed in contact with emulsin, it is transformed by a species of fermentation into hydrocyanic acid, hydride of benzoyl (essential oil of bitter almonds), and

Bitter almonds contain both amygdalin and emulsin, and, therefore, when treated with water they yield the well known essential oil mixed with hydrocyanic acid; but sweet almonds contain emulsin and no amygdalin, and consequently do not yield these products when macerated with water. AMYGDALUS-Medical Properties of. Amygdalus communis, a tree native of Asia and Africa, cultivated in the southern parts of Europe,

of which there are two varieties, sweet and bitter. Of the sweet almonds, the parts which are officinal are the seeds or kernels. When covered with the skin, these are of a clove-brown colour, smooth, with vessels traversing the skin, and forming a raphe. Deprived of the skin, the egg-shaped seed, formed of two cotyledons, is seen of a white colour. They have a sweet and mucilaginous, rather oily taste, and scarcely any odour when fresh but when spoiled a disagreeable rancid

taste.

Almonds, as an article of dessert, are nutritive, but rather indigestible. In some persons they occasion-more particularly bitter almonds-an eruption similar to nettle-rash, and other troublesome symptoms.

Oil of Almonds.-The almonds having been freed from the skins, must be bruised, and pressed in the cold, or, if warmed, they must be pressed in iron presses. The oil when first obtained is turbid, but becomes pure by time or by filtration. It is yellowish, or nearly white, if the almonds have been completely freed from the skins before being pressed, translucent, and when cold-drawn is without odour. The taste is purely oily. Specific gravity, 0·911 to 0.920. Consists of, elain 75; stearin 25. It is fluid at the ordinary temperature of the air, and rarely or never becomes turbid or white. Alcohol when cold takes up 1-25th part. Sulphuric ether and the volatile oils combine with it in every proportion Caustic potash forms with it a very solid soap. When it has been carefully expressed, it, does not become rancid so easily as is

believed.

It may be obtained from either variety, but is yielded in greatest abundance by the bitter almond: 10 lbs. of sweet, when cold-drawn, yield from 4 to 4 lbs.; 16 lbs. of bitter almonds yield 7 lbs.

Almonds which have become rancid yet yield by expression good oil, if a little calcined magnesia be added to the bruised almonds before being subjected to pressure.

Almond oil is often adulterated with poppy oil. It is employed more as an external application, especially to the ears, than internally. It is

also used for hair oil.

Amygdal. Amara, bitter almonds, are smaller and flatter than the sweet. Those most esteemed come from Provence; those least esteemed from Barbary. They have a very bitter taste, and scarcely any odour, but if rubbed between the fingers with a little water, they emit a peculiarly agreeable odour. Triturated with water, they form an emulsion, which by distillation yields a volatile oil, containing hydrocyanic acid. This oil is procured in very variable quantity; 1 lb. of almonds yielding in some instances 1 drachm, in others only 50 grains, in others only 10 grains.

A fat or fixed oil is also contained, which may be procured by

expression. Hence, in the Pharmacopoeia, Oleum amygdalarum is directed to be expressed from the kernels of either variety. For the sake of economy, this fixed oil is first procured, and the cake which remains is employed either to yield the volatile oil containing hydrocyanic acid or to furnish amygdalin.

The essential oil of bitter almonds is prepared by distilling the emulsion of bitter almonds.

It is sold in different degrees of dilution to cooks, confectioners, and others, to flavour cakes and liqueurs, under the name of essence of ratafia, peach-essence, &c. (See 'Lancet,' June 8, 1844; and 'The Chemist, vol. v. p. 335.) From its indiscriminate use, as well as variable strength, many fatal cases result from it. It is also used as a criminal means of destroying life. [AMYGDALIN; BENZOYL, HYDRIDE OF.]

The following are some of the most important of these compounds :

Hydrated oxide of amyl (Amylic alcohol) (CHO). This body,

from which amyl and all its compounds are derived, is formed along with common alcohol during the fermentation of the mash of potato starch, and the starch of common grains. The process of its formation under these circumstances is not well understood, although it undoubtedly depends on some peculiar conditions of the fermentation. It is on account of its being obtained from the decomposition of starch (Amylum) that it has obtained its name. The latter portions of the alcohol produced in the distillation of these fermented matters contain which consists of amylic alcohol. It is the occurrence of this oil in an oil separable by water and termed Fusel oil, the greater portion of crude distilled spirits that gives them a part of their noxious qualities, and it is the object of the distiller to prevent the development of fusel oil. When fusel oil is submitted to distillation, its boiling point gradually rises until it reaches 270° F., at which point it then frequently remains stationary during the remainder of the distillation. The portion of the fusel oil distilling at 270° is pure hydrated oxide of amyl. It is a colourless, somewhat oily liquid, almost insoluble in water, and boiling at a temperature of 270°. It has a powerful odour, which is very unpleasant, and produces when inhaled a sense of suffocation. Its taste is given off, and valeric acid is formed, which unites with the potash. is nauseous and acrid. When heated in contact with potash, hydrogen Distilled with a mixture of dilute sulphuric acid and bichromate of potash, it also yields valeric acid,

and is now the source of the salts of this acid used in medicine. When heated with dry phosphoric acid, it yields the carbo-hydrogen C10 H10, which is isomeric with olefiant gas, and which is known by the name of Amylene or Valerene. This substance has lately obtained some repute, since it has been administered in common with chloroform and ether as an anesthetic. [ANESTHETICS; MATERIA MEDICA; ALCOHOLS.]

Iodide of Amyl (C,H,,I) -This compound is formed by distilling together a mixture of 10 parts of amylic alcohol, 12 parts of iodine, and 14 parts of phosphorus. The product, after being washed with water, and then dried over chloride of calcium, is again submitted to rectification, a thermometer being inserted through the tubulure of the retort. That portion which distils over whilst the thermometer stands at 295° F. is pure iodide of amyl, and must be collected apart.

Its

Iodide of amyl is a colourless and transparent liquid, refracting light strongly, possessing a slight ethereal odour and a pungent taste. specific gravity is 1511. It boils at 295° F. Exposed to direct sunlight, it gradually becomes brown from the separation of free iodine. It is decomposed by an alcoholic solution of potash, amylic alcohol being reproduced.