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with no impediment so great as to hinder him from carrying his con. quering arms to the utmost limits of Europe. This done he threw the cup into the Hellespont, with a golden bowl, and a Persian scymitar; and the foot and horse began to pass over that bridge, which was next to the Euxine, while the carriages and beasts of burden passed over the other, which was placed nearer the Ægean sea. The bridges were boarded, and covered over with earth, having rails on each side, that the horses and cattle might not be frightened at the sight of the sea. The army spent seven days and nights in passing over, though they marched day and night, without intermission, and were, by frequent blows, obliged to quicken their pace. At the same time, the fleet made to the coasts of Europe. After the whole army was passed, Xerxes advanced with his land forces, through the Thracian Chersonesus to Doriscus, a city at the mouth of the river Hebrus, in Thrace: but the fleet steered a quite different course, standing to the westward for the promontory of Sarpedon, where they were commanded to attend farther orders. Xerxes, having encamped in the large plains of Doriscus, and judg. ing them convenient for reviewing and numbering his troops, dispatched orders to his admirals to bring the fleet to the adjacent shore, that he might take an account both of his sea and land forces. His land army, upon the muster, was found to consist of one million seven hundred thousand foot, and fourscore thousand horse; which, together with twenty thousand men that conducted the camels, and took care of the baggage, amounted to one million eight hundred thousand men. His fleet consisted of twelve hundred and seven large ships, and three thousand gallies and transports: on board all these vessels, there were found to be five hundred and seventeen thousand six hundred and ten men. So that the whole number of sea and land forces, which Xerxes led out of Asia to invade Greece, amounted to two millions three hundred and seventeen thousand six hundred and ten men. We are told, that, on his passing the Hellespont, to enter Europe, an inhabitant of that country cried out: "O Jupiter, why art thou come to destroy Greece, in the shape of a Persian, and under the name of Xerxes, with all mankind following thee; whereas thy own power is sufficient to do this, without their assistance?" After he had entered Europe, the nations on this side the Hellespont that submitted to him, added to his land forces three hundred thousand more, and two hundred and twenty ships to his fleet, on board of which were

twenty-four thousand men. So that the whole number of his forces, when he arrived at Thermopyla, was two millions six hundred and forty-one thousand six hundred and ten men, without including servants, eunuchs, women, sutlers, and other people of that sort, who were computed to equal the number of the forces: so that the whole multitude of persons that followed Xerxes in this expedition, amounted to five millions two hundred and eighty-three thousand two hundred and twenty. Among these millions of men, there was not one that could vie with Xerxes, either in comeliness or stature, or that seemed more worthy of that great empire. But this is a poor commendation, when it is not accompanied with other qualifica tions. Accordingly, Justin, after he has mentioned the number of his troops, emphatically concludes, but this vast body wanted a head." Besides the subordinate generals of each nation, who com. manded the troops of their respective countries, the whole army was under the command of six Persian generals; viz. Mardonius, the son of Gobry us; Triatatœchmes, the son of Artabanus; Smerdones. the son of Otanes (the two latter were cousins to Xerxes); Masistus, the son of Darius by Atossa; Gerges, the son of Ariazus; and Megaby zus, the son of the celebrated Zopyrus. The ten thousand Persians, who were called the Immortal Band, obeyed no other commander but Hydarnes. The fleet was commanded by four Persian admirals: and likewise the cavalry had their particu lar generals and commanders. [Anc. Univ. Hist.

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SECTION IV.

Spectacle of a Sea fight at Rome.

AUGUSTUS, to divert his mind from fixing on his domestic mis. fortunes, exhibited the most magnificent and expensive shews that had ever been seen at Rome. Chariot races in the Circus, representations on the stage, combats by gladiators, &c. were now become common. Augustus, therefore, the better to divert both himself and the people, revived these sports, which had been for a considerable time laid aside, on account of the extraordinary charges that attended them. He caused a canal to be dug eighteen hundred paces in length, and two hundred in breadth, conveying into it the Flaminian water, and building scaffolds quite round it, capable of holding numberless multitudes of spectators. And in. deed the concourse of people was so great, that the emperor was

obliged to place guards in all quarters of the city, lest the thieves should lay hold of that opportunity to plunder the empty and abandoned houses. Augustus had frequently entertained the people with fights of lions, tygers, elephants, rhinoceroses, &c. but now the new canal appeared all on a sudden covered with crocodiles, of which thirty-six were killed by Egyptians brought from the banks of the Nile for that purpose. The multitude were highly delighted by this sight, which was quite new; but the sea-fight, which ensued, allorded them still greater diversion. For, at the opposite ends of the lake or canal, two fleets appeared, the gallies one being built after the Greek, and those of the other after he Persian, mauner. Both fleets engaged; and, as they fought in good earnest, most of the combatants being persons sentenced to death, the battle proved very bloody. [Anc. Univ. Hist.

CHAP. VII.

BRIDGES AND LIGHT-HOUSES.

SECTION 1.

Bridges most curious or interesting.

A BRIDGE is the work of carpentry or masonry, built on a river, canal, or the lake, for the convenience of passing from one side to the other; and may be considered as a road over water, supported by one or more arches, and these again supported by proper piers or buttments. Besides these essential parts, may be added the paving at top, the banquet, or raised footway, on each side, leav ing a sufficient breadth in the middle for horses and carriages, also the parapet wall either with or without a balustrade, or other ornamental and useful parts. The breadth of a bridge for a great city should be such, as to allow an easy passage for three carriages and two horsemen abreast in the middle way, and for three foot pas. sengers in the same manner on each banquet: but for other smaller bridges a less breadth.

The conditions required in a bridge are, that it be well designed, commodious, durable, and suitably decorated. It should be of such a height as to be quite convenient for the passage over it, and

yet easily admitting through its arches the vessels that navigate upon it, and all the water, even at high tides and floods: the neglect of this precept has been the ruin of many bridges. Bridges are commonly continued in a straight direction perpendicular to the stream; though some think they should be made convex towards the stream, the better to resist floods, &c. And bridges of this sort have been executed in some places, as Pont St. Esprit, near Lyons. Again, a bridge should not be made in too narrow a part of a navigable river, or one subject to tides or floods; because, the breadth being still more contracted by the piers, this will increase the depth, velocity, and fall of the water under the arches, and endanger the whole bridge and navigation. There ought to be an uneven number of arches, or an even number of piers; both that the middle of the stream or chief current may flow freely without the interruption of a pier; and that the two halves of the bridge, by gradually rising from the ends to the middle, may there meet in the highest and largest arch; and also, that by being open in the middle, the eye in viewing it, may look directly through there. When the middle and ends are of different heights, their difference however ought not to be great in proportion to the length, that the ascent and descent may be easy; and in that case also it is more beautiful to make the top in one continued curve, than two straight lines forming an angle in the middle. Bridges should rather be of few and large arches then of many smaller ones, if the height and situation will possibly allow of it; for this will leave more free passage for the water and navi. gation, and be a great saving in materials and labour, as there will be fewer piers and centres, and the arches, &c. will require less materials; a remarkable instance of which appears in the difference between the bridges of Westminster and Blackfriars, the expence of the former being more than double the latter.

For the proper execution of a bridge, and making an estimate of the expence, &c., it is necessary to have three plans, three sections, and an elevation. The three plans are so many horizontal sections, viz. first a plan of the foundation under the piers, with the particular circumstances attending it, whether of gratings, planks, piles, &c.; the second is the plan of the piers and arches; and the third is the plan of the superstructure, with the paved road and banquet. The three sections are vertical ones, the first of them a longitudinal section from end to end of the bridge, and

through the middle of the breadth; the second a transverse one, or across it, and through the summit of an arch; and the third also across, but taken upon a pier. The elevation is an orthographic projection of one side or face of the bridge, or its appearance as viewed at a distance, shewing the exterior aspect of the materials, with the manner in which they are disposed, &c.

In the construction of stone bridges many difficulties must be encountered, particularly those of laying foundations and walling under water; these are best overcome by means of the coffer.dam. A due regard must be paid to the size and shape of the arch, and the magnitude of the pier. Much information on these subjects may be obtained from the works of Alberti, Gautier, Blonde Rio, Palladio, Labelye, Perronet, and the ingenious and useful treatises of Dr. Hutton and M. Bassuet.

The chief foreign bridges are, the bridge of Trajan, over the Danube, the bridge of Avignon, the Pont de Garde, in France, the bridge at Munster, in Bothnia, the aqueduct bridge of Alcantara, near Lisbon, and the Rialto of Venice. There are nearly 500 bridges of different sizes over the canals at Venice. The Rialto, the principal of these, is esteemed a master-piece of art: it consists of one flat and bold arch, nearly 100 feet span, and only 23 feet high above the water, and was built in 1588,-1591, after a design by Michael Angelo. The breadth of the bridge, which is 43 feet, is divided by two rows of shops, into three nar. row streets, that in the middle being the widest; and there is in the centre an open archway, by which the three streets communicate with one another. At each end of the Rialto, is an ascent of 56 steps the view from its summit is very lively and magnificent. The whole exterior of the shops and of the bridge is of marble. The foundation extends 90 feet, and rests upon 12,000 elm piles. This structure cost the republic 250,000 ducats.

We have many bridges of considerable note in our own country: such is the bridge at York, whose master arch in the middle, is 82 feet and a half in the clear wide, and 27 feet high. Rochester bridge is built in the same style with that of London; it is 550 feet long, and consists of 11 arches, the biggest of which is more than 50 feet. The two middle arches of this fine old bridge have been recently thrown into one by that skilful and scientific architect Mr. Daniel Alexander. The bridge of Blenheim consists of three arches, the chief of which spans 101 feet. There is a bridge over the river Don, near Old Aberdeen, very much celebrated, in

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