and gives the least strain to the muscles. They should occasionally found in the rudest and most uncivilized never be suffered to hang down. The left hand should states of society, and which is even more powerful than never move alone, but accommodate itself to the mo- the most laboured forms of art. The address of an tions of the right. The hands should generally be Indian warrior has frequently been found to operate open: but in expressions of compunction and anger in a most powerful way on the passions and to rouse they may be closed. The feet should continue steady, the consciousness of right that had previously lain dorand not give the body a wavering and giddy motion, mant in the mind of his oppressor. As however we by frequently shifting, though some persons fall into are not all of us gifted with this innate power, and as that habit, without moving their feet. Philip the many must from necessity make a profession of the Roman orator was wont to tell his friends, "he was art who are ignorant of its natural attributes, care has never fit to talk till he had warmed his arm." He been taken to select from the great masters in oratory doubtless, therefore, used a more violent motion with those rules by which they succeeded in tracing out his arms and hands than is common with us. And the path to eminence. Cicero calls the arm projected, "the orator's weapon." To speak low at first has the appearance of modesty, and is best for the voice, which, by rising gradually, will with more ease be carried to any pitch that may be afterwards necessary, without straining it. However, some variation of the voice is always proper, to give it harmony. Sometimes it is not improper for an orator to set out with a considerable degree of warmth, expressed by such an elevation of the voice, and gestures of the body, as are suited to represent the emotions of his mind. But this is not ordinarily the case. We have some happy instances of this in Cicero; as in his oration for Roscius, where the heinousness of the charge could not but excite his indignation against the accusers. And in that against Piso, and the first two against Catiline, which begin in the same manner, from the resentment he had conceived and wished to inspire against their persons and conduct.

In narration the voice ought to be raised to a higher pitch. Facts should be stated distinctly and accurately, with a proper emphasis laid upon the principal circumstances. The proposition should be delivered with a clear and audible voice, and its divisions distinctly marked. The confirmation admits of a great variety both of voice and gesture; and the reasoning ought to be accompanied with suitable actions. In confutation, the arguments of the opposite party should be stated plainly and distinctly, unless they appear unworthy of a serious answer, in which case they may be answered with humour, or exposed. Tubero, having made it part of his charge against Ligarius that he was in Africa during the civil war between Cæsar and Pompey, Cicero, in his reply, said, "Cæsar, my kinsman, Tubero has laid before you a new crime, and till this day unheard of, that Q. Ligarius was in Africa." In a conclusion, both the voice and gesture should be brisk and sprightly, which may seem to arise from a sense of the speaker's opinion of the goodness of his cause, and that he has offered nothing but what is agreeable to reason and truth; as likewise from his assurance that the audience agree with him in the same sentiments. In every undertaking that requires care and thought persons are apt at first to be sedate and moderate; but when it is drawing to an end, and is nearly finished, it is very natural to appear more gay. If an enumeration of the principal arguments of the discourse be convenient, as it sometimes is, where they are pretty numerous, or the discourse is long, they ought to be expressed in the most clear and forcible

manner.

We have in the preceding article laid before our readers the principal rules employed for the guidance of those who would attain eminence in the art of oratory. There is however a natural eloquence which is

ORCHALL, OF ARGOL; a species of lichen, celebrated for yielding a fine purple colour, which is employed in dyeing. It is chiefly obtained, in commerce, from the Canaries, Cape Verd islands, and the Grecian archipelago. It is the substance generally employed for colouring the spirits of wine used in thermometers; and it is a remarkable circumstance that, after the colour has been destroyed by time, it is again restored on breaking the tubes.

ORCHESTRA, in architecture; that portion of the area of a theatre in which the band is usually placed. In the early English theatres, the musicians were placed in a small balcony over the stage, and it was not till a comparatively late period that they occupied the front of the pit. During the performance of oratorios, a temporary orchestra is erected on the stage. In the Grecian theatres, the orchestra was that part of the proscenium, or stage, where the chorus used to dance. In the middle of it was placed the pulpit, or rostrum. The orchestra was semicircular, and surrounded with seats. In the Roman theatres it made no part of the scena, but answered pretty nearly to the pit in our playhouses, being taken up with seats for senators, magistrates, vestals, and other persons of distinction. The actors never went down into it.

ORDER, in architecture, is a system of the several members, ornaments, and proportions of columns and pilasters; or a regular arrangement of the projecting parts of a building, especially the columns, so as to form one beautiful whole. For a description of the various orders see ARCHItecture.

ORDNANCE, in military affairs; a general name for all large guns used in war. It is not certainly known at what period this species of missile weapon was first employed. The introduction of them into the western part of the world is only of modern date, but it is certain that in some parts of Asia they have been used for many ages, though in a very rude and imperfect manner. Philostratus speaks of a city near the river Hyphasis, in the Indies, which was said to be impregnable, and that its inhabitants were relations of the gods, because they threw thunder and lightning upon their enemies; and other Greek authors speak of the same weapons having been employed against Alexander the Great. One thing, however, seems certain, that guns were used in China as far back as the year of Christ 85, and that they have continued in use in that country ever since.

The first hint of the invention of guns in Europe is in the works of Roger Bacon, who flourished in the thirteenth century. In a treatise written by him about the year 1280 he proposes to apply the violent explosive force of gunpowder for the destruction of armies. And, though it is certainly known that the composition of gunpowder is described by that author, yet the invention has usually been ascribed to Bar

Names.

Cannon royal, or carthoun
Bastard cannon, or carthoun 36

tholdus Schwartz, a German monk, who, it is said, these uncommon names were generally abolished, and discovered it only in the year 1320. Schwartz having the following more universal ones took place, viz :— for some purpose placed pounded nitre, sulphur, Weight of ball. Weight of piece, and charcoal together in a mortar, which he afterPounders. 48 wards covered imperfectly with a stone, a spark of fire accidentally fell into the mortar, which, setting the mixture on fire, the explosion blew the stone to a considerable distance. Hence it is probable that Schwartz might have discovered the simplest method of applying it in war, but that Bacon proposed its first application in ordnance.

Demi-carthoun
Whole culverins
Demi-culverins
Falcon.

Sacker

{

Falconet
Rabinet

largest size
ordinary
lowest sort

Soon after, the time of Schwartz we find guns These were commonly used as instruments of war. originally made of iron bars soldered together and Basilisk strengthened by strong iron hoops or rings, several Serpentine of which are still to be seen in the Tower of London Aspic and in the Warren at Woolwich. Others were made Dragon of thin sheets of iron rolled up together and hooped, Syren and on particular emergencies some have been made of leather and of lead, with plates of iron or copper. Stone balls were thrown out of them, and a small quantity of powder used on account of their weakness. They were of a cylindrical form, without ornaments, and were placed on their carriages by rings. At a later period the Tyrolese successfully resisted the French revolutionary generals with wooden cannon hooped with iron.

Moyens

in cwts.

90

79

24

60

18

50

These singular names, derived from beasts and birds of prey, were adopted on account of some peculiar property which they were supposed to possess, as the falconet, falcon, sacker, culverin, &c., for their swiftness in flying; the basilisk, serpentine, aspic, dragon, syren, &c., for their cruelty. But, at present, cannon take their names from the weight of a ball adapted to their peculiar caliber. Thus a piece that discharges a cast-iron ball of twenty-four pounds is called a twenty-four-pounder, one that carries a ball of twelve pounds is called a twelve-pounder, and so of the rest, divided into the following sorts, viz.: Ship-guns, consisting of 42, 36, 32, 24, 18, 12, 9, 6, and 3 pounders; Garrison-guns, of 42, 32, 24, 18, 12, 9, and 6 pounders; Battering-guns, of 24, 18, and 12 pounders; and Field-pieces, of 12, 9, 6, 3, 2, 14, 1, and pounders.

The Venetians used cannon at the siege of Chioggia, in 1366, which were brought thither by two Germans, with some powder and leaden balls, and also in their wars with the Genoese in 1379. But, before that, king Edward III. is said to have made use of cannon at the battle of Cressy in 1346, and at the siege of Calais in 1347. Cannon were employed by the Turks at the siege of Constantinople, then in possession of the Christians, in 1394, and in that of 1452, which threw balls of 100 lbs., but they commonly burst at the first, second, or third firing. Louis XII. had one cast at Tours of the same size, which threw a ball from the Bastile to Charenton; one of these extraordinary cannon was taken at the siege of Dieu in 1546, by Don John de Castro, and is now in the castle of St. Julian da Barra, ten miles from Lisbon; the length of it is twenty feet seven inches, its dia-iron. Three side-cutters equidistant were requisite meter at the middle six feet three inches, and it threw a ball of 100 lbs. weight. It has neither dolphins, rings, nor button, is of an unusual kind of metal, and has an inscription upon it which says it was cast in 1400.

Cannon were formerly dignified with uncommon names. Thus Louis XII. in 1503 had twelve brass cannon cast of an extraordinary size, called after the names of the twelve peers of France. The Spanish and Portuguese called them after their saints. The emperor Charles V. when he marched against Tunis cast the twelve apostles. At Milan there is a seventypounder, called the Pimontelle; and one at Bois-leduc called the Devil. A sixty-pounder at Dover castle, called Queen Elizabeth's Pocket Pistol. An eighty-pounder in the Tower of London, brought there from Edinburgh Castle, called Mount's-meg. An eighty-pounder in the royal arsenal at Berlin, called the Thunderer. An eighty-pounder at Malaga, called the Terrible. Two curious sixty-pounders in the arsenal at Bremen, called the Messengers of Bad News. And, lastly, an uncommon seventy-pounder in the castle of St. Angelo at Rome, made of the nails that fastened the copper plates which covered the ancient Pantheon. In the beginning of the fifteenth century

Till the middle of the last century iron cannons were cast with a cylindrical cavity, nearly of the dimensions of the caliber of the piece, which was afterwards enlarged to the proper caliber by means of steel-cutters fixed into the dog-head of a boring-har

to preserve the caliber straight and cylindrical; and a single cutter was used at the end of the bar to smooth the breech of the piece. In boring ordnance cast hollow, the piece was fixed upon a carriage that could be moved backwards and forwards in a direct line with the centre of a water-wheel; in this centre was fixed the boring bar, of a sufficient length to reach up to the breech of the piece, or more properly to the further end of the caliber. The carriage with the piece being drawn backwards from the centre of the water-wheel to introduce the boring and finishing bars, it was then pressed forward upon this bar by means of levers, weights, &c.; and, the water-wheel being set going, the bar and fullers were turned round, and thus smoothed the caliber to its proper dimensions.

Experience at last pointed out many inconveniences arising from the method of casting guns hollow, and widening the calibers by these boring bars. For the body of iron of the hollow gun being, at casting, in contact with the core that formed the caliber, it began to consolidate unequally, and cavities were formed in the body of the cannon.

To remedy these defects, iron guns are now cast solid, by which means the column of iron is greatly enlarged and the metal more compressed.

ORDONNANCE, in architecture, is the composition [ence and to the ingredients of mineralization: for of a building, and the disposition of its parts, both instance, whether they are acids or sulphurets. But with regard to the whole and to one another; or, as both sorts of metals, native and mineralized, also Mr. Evelyn expresses it, "determining the measure make their appearance in very different forms, and of what is assigned to the several apartments. Thus this difference is of the greatest importance in the ordonnance is the judicious contrivance of the plan method of separation. They either break in such or outline; as when the court or hall is neither too large pieces that they may be kept clean by themlarge nor too small, the court affords convenient light selves, or they break disseminated in larger or to the apartments about it, and the chambers, &c., smaller particles through the gangue, so that they are of a proper size. When these divisions are either must be freed first by many different operations before too great or too small with respect to the whole, as they can be given over to smelting. The former are where there is a large court to a small house, or a called pure ores, and the most simple preparation is small hall to a magnificent palace, the fault is in the sufficient to make them fit for smelting. But those ordonnance." which are disseminated, or mixed, have to go through different manipulations. These are again divided into coarsely disseminated and finely disseminated orcs : when the particles of ore strewed through the gangue have such a size that they may be separated from it by the hammer, stamps, and percussion sieves, they are called coarsely disseminated. They are called finely disseminated if the metalliferous particles are so small and minute that they can be prepared for smelting merely by stamping and washing. In most modes of reduction, use is made of water, by means of which the different substances of ores and gangues separate, and either precipitate or settle in layers above one another, or are carried away in part by the water, and sink in part through their specific weight.

ORDONNANCE, in painting, is used for the disposition of the parts of a picture, either with regard to the whole piece or to the several parts, as the groups, masses, contrasts, &c.

ORES. Metals, when found in a state of combina tion with other substances, have the name of ores. They are in general deposited in veins of various thickness, and at various depths in the earth. The mode of obtaining them is to penetrate from the surface of the earth to the vein, and then to follow it in whatever direction it may lie. The hollow places thus formed are called mines, and the men employed in them are denominated miners. When the veins are at a great depth, or extend to any considerable distance beneath the surface of the earth, it is necessary, at intervals, to make openings, or shafts, to the sur- It will be easily conceived that in this process much face, for the admission and circulation of air; and also depends, not merely on the specific weight, but also on to draw off the water, which collects at the bottom, the shape of the particle and its power of coherence. by means of drains, pumps, or steam-engines, as the As to shape, a difference has to be made chiefly besituation or circumstances require. After the metallic tween fossils of a leafy and a compact structure. The ores are drawn from the mine, they in general go former are separated into thin, scale-like particles, the through several processes before they are in a state latter into corns, which are pretty equal in length, fit for use. Some of them are first washed in run- breadth, and thickness. The leafy ones are called during ning water, to clean them from loose, earthy particles. the reduction spathy, the compact ones corny. Both They are then piled together with combustible sub-must, during the whole of the reduction, be separated stances, and burnt, or roasted, for the purpose of carefully, since the water has just an opposite effect ridding them of the sulphur or arsenic with which on each of them. Hardness and coherency also have they may happen to be combined, and which rises a considerable effect on the reduction. But it is suffrom them in a state of fume or smoke. Thus having ficient to keep separate hard and coherent fossils been freed from impurities, they undergo the opera- from soft and less coherent ones; for instance, from tion of melting, in furnaces constructed according to clayey, earthy, and crumbling ones. According to the nature of the respective metals, or the uses to these divisions the reduction must be pursued in a which they are to be subsequently applied. manner adapted to the wants of each of them. We may, therefore, give the sense of the German word aufbereitung, by mechanical separation of the useless fossils which have been sent from the mine from the useful, and also the subseparation of the latter from one another. It is never otherwise than We have seen that the different or heterogeneous mechanical. Chemical is the metallurgical reduction. states in which metals appear in the earth make it The necessity and usefulness of mechanical conimpossible to extract them immediately without a pre-centration or reduction speaks for itself, particularly vious preparation. They must, therefore, be cleared in districts where very different ores make their or separated first from those rocks, earths, or other particles, technically called gangue, which adhere to them, and a distinction or classification of them must be made with regard to their future treatment. After being thus separated or classified, they must be subjected to those further processes through which they present themselves as metals in the narrowest sense of the word.

Having thus given a general outline of the mode of converting ores into their metallic states, we may now proceed to examine the very important processes which are resorted to in practice in the most celebrated mining districts.

The first-named process is termed reduction. Ores are usually subdivided in the reduction into those termed native and those which are mineralized; this division however applies only to their mechanical treatment, without any reference to chemical differ

appearance together. Without a due rejection and separation of useless substances, smelting would become very difficult and injurious. But even if the minerals which appear together are not obnoxious in the process of smelting, or if the ores make their appearance pretty compact and pure, a preliminary separation may be necessary. For instance, copper ores often appear together along with ironstone-two minerals which are so different that it would be absolutely impossible to separate them from one another by the same smelting process, and whose junction will make each of the metals unfit for the purposes required.

The chemical character of the minerals which ac- | ruddling box. To the washing works with which, company the ore must be known, to judge whether principally, engines co-operate, belong the percusthey are obnoxious in the process of smelting or not. Further, the structure of the substances to be concentrated must be well considered, and the treatment regulated accordingly.

sion or tossing tables; but between these two chief divisions of mechanical concentration there is still a labour which in a certain measure may be considered as belonging to both, and which connects both together; this is the washing or separating by the tossing sieve, which has of late made so great a revolution in the concentration works of those mining districts in which it is applicable to the qualities of the ores; by it the pure pieces of ore are separated, whereby expense of labour is created as well as ore lost. Equal qualities of the different ores are obtained; and most of the gangue is got rid of without causing further labour.

After this it is necessary to become acquainted with the greater or smaller degree of brightness or frangibility of the single minerals, and from them to judge what power is requisite to reduce them into smaller pieces or dust. In one word, the coherency of each sort must be accurately known, if the metal-without reducing them to an unnecessarily small size, lurgist does not wish to stamp one class to atoms, while the other is not enough stamped, and to lose in one way or the other a great deal of ore: at least, it is a principal requisite to know well the specific weight of the minerals which are to be worked. The mechanical concentration is almost wholly founded on this knowledge, as the dressing is to separate the minerals, according to their specific weight, by means of the water.

Proximity to water is most desirable; but, if this cannot be had, the ores must be cleansed and separated with so much greater care from all useless parts, in order to avoid the expense of freight on their transfer. It is very rare that one single treatment is sufficient for any ores, but generally they must go through different and repeated treatments. It is, therefore, necessary to let one treatment follow the other, so that each separate process facilitates and prepares for the following; in short, every thing should be done with system.

It is difficult to decide wherein the chief advantage of this engine lies, whether in the accurate classification of all the ores, and rejection of the useless substances, and consequent facilitation and simplification of all the works, or in the great saving of the wages in every concentration, as one man, with two of these engines, separates or classifies now, on quartz, 240 cwt. in eight hours, for 4 grains (sixpence), which a few years back cost 18 (three dollars) for manipulation.

Dressing signifies to free to the utmost, by mechanical means, all the fossils, or ores, which have been extracted by the miner, from such particles as are obnoxious to the amalgamation or smelting process. It is an art in itself, and forms so essential a part in mining that the smelter must know it. Ores If, therefore, the ores of a certain mine are such which are to be put into furnaces, and smelted, that they cannot be completely cleaned, or got out, should have as little dust as possible; but such as by one treatment, the part which has been got out are to be amalgamated, or to be roasted with an clean should be put on one side, and the rest should admixture, are to be reduced as impalpably as posbe given over to a different treatment; but one sible. Classification of the ores is likewise necesmust take care not to subject this latter part again sary, not only for the smelting and amalgamating to the same treatment, and so let it afterwards process, but also for fixing their price and value. get amongst the refuse, because this would cause a We may next examine, somewhat briefly, the loss not only of time, but also of ore. If, for in- initiatory process employed in converting ores into stance, we have two sorts of ores; one coarsely dis-metalline bodies, and then proceed to a description seminated, the other finely, which we wish to concentrate by "tossing sieves." The first had been separated from the latter; but the latter, though considerably richer, is so finely disseminated that it is not fit for the tossing sieve; yet it merits a further concentration; this, therefore, must come on the percussion tables, and is to be stamped finer, and to be tossed again in the sieves, because the ore would otherwise be lost, and time and trouble would be applied in vain.

The whole mechanical concentration falls under two principal heads; the separation by hammer, or stamps, and the washing works. The first always precedes the latter, and might, therefore, be looked upon as a preparatory work: it consists of the separation of the ores from the gangue, in the mine and above ground; the beating off by the separation hammer, and by the picking on the picking table.

The washing works may be subdivided into such as are done by men's hands, and those which are executed by engines; they are both preceded by the stamping, which is again to be divided into dry stamping and wet stamping. The washing works, which are done principally by men, fall into three divisions; first, as a preparatory work, the schlemmen in the slime pit; after this the washing on tables, or inclined planes; and, lastly, ruddling in the

of those used in the preparation of copper. We may conjecture that the first rude process by which metals were extracted from the ores was that of putting a quantity of ore upon a heap of wood and setting the pile on fire, in conformity to the manner in which ores were smelted during the burning of forests; but as the force of the fire is greatly diminished by the dispersion of its flame, and as the air acts more forcibly in exciting fire when it rushes upon it with greater velocity, it is likely that the heap of wood and ore would soon be surrounded with a wall of stone, in which sufficient openings would be left for the entrance of the air, and thus a kind of furnace would be constructed.

The Peruvians, we are told, had discovered the art of smelting and refining silver, either by the simple application of fire, or, where the ore was more stubborn and impregnated with foreign substances, by placing it in small ovens or furnaces on high grounds, so artificially constructed that the draught of air performed the function of a bellows, a machine with which they were totally unacquainted. This method of smelting ores on high grounds without the assistance of a bellows, or at least of bellows moved by water, seems to have been formerly practised in other countries as well as in Peru. There are several places in Derbyshire, called boles by the inhabitants, where