The Surgeon and Chaplain resemble the same officers in

the army.

358. Marines have nothing to do in working the ship, but defend it in war, and attack the enemy when fighting. There is generally a company on board each ship, about forty in number, under a captain and two lieutenants. The present establishment of marines amounts to more than 30,000. Their principal stations are at Chatham, Woolwich, and Portsmouth. In a sca-fight, their small arms are of very great advantage, in scouring the decks of the enemy, and when they have been long enough at sea, they must be infinitely preferable to seamen, if the enemy attempts to board by raising a battalion with their fixed bayonets.

359. Officers of the navy are, the treasurer who receives monies out of the exchequer, to pay charges of the navy. The controller who attends and controls all payments of wages, knows all the rates of stores, examines and audits all accounts. The surveyor knows the state of all stores, sees all wants supplied, estimates repairs, &c. and at the end of each voyage, audits and states all accounts. The clerk of the acts, records all orders, contracts, bills, warrants, &c.

Navy-Bills, or victualling-bills, are orders for the payment of money, issued by the commissioners of the navy on the treasury of the navy, in payment for stores, &c. furnished by contract for the use of his Majesty's dock yards, and the navy. These bills since 1796, are negotiated like bills of exchange, payable at ninety days after date, and bearing inte rest at 31d. per. cent. per diem.

The privileges conferred on sailors are much the same as on soldiers, with regard to relief, when maimed, wounded, or superannuated. Greenwich Hospital receives such seamen as are disabled from further service, and provides for the widows and children of such as are slain.

SECTION VII,

TELEGRAPHS.

360. It immediately follows military and naval tactics, that we give the reader some idea of telegraphs, those modes of quick and certain communication between one place and another.

The telegraph, though brought into general use

by circumstances arising from the French Revolution, is of great antiquity, for the principle appears to have been known from the earliest ages, as the ancient Greeks used signals to convey information to distant friends. The news of the burning of Troy was conveyed to Greece by means of telegraphic signals, else how could that event be known in that country soon after it had happened?

The Chinese, when they send couriers on the great canal, or to have every thing prepared when any great man travels, make signals by fire, from one day's journey to another. Most barbarous nations used, formerly, to give the alarm of war, by fires lighted on hills, or rising grounds. Various modes have been adopted for communicating intelligence by signals for every letter in the alphabet, which are observed by telescopes, and repeated at the respective stations. Both day and night telegraphs have been proposed by different writers, and others have insisted on the adoption of a vocabulary in which every sign should represent a word, instead of a single letter as now practised.

The late telegraph, set up by government in a chain of stations from the admiralty to the sea-coast, consists of six octagonal boards; each of which is poised upon an axis in a frame. And this is done in such a manner, that the board can be either placed vertically, so as to appear with its full size to the observer at the nearest station, or it becomes invisible to him, by being placed horizontally, so that the narrow edge alone is exposed, which edge is invisible from a distance. These six boards make thirty-six changes by the most plain and simple mode of working; and will make many more if more were necessary. By a change in the position of one of these octagonal boards, any letter may be made, and in certain positions, a variety of things may be signified, according to the will of the persons at the two extreme posts, employed in making the signals. Thus one board being in an horizontal position, and the others shut, or in a perpendicular situation, may denote the letter a; two only being in an horizontal position may give the letter b: three in the same manner the letter c, and so on. As there may be made as many changes with these boards, as with the same number of bells, the letters of the alphabet may be made with ease, and a sufficient number of signals may be formed for extraordinary purposes.

These have been supplanted by a mast or pole at each station in which are fixed arms that move by pullies and cords ;

and according to the angle these arms make with the pole so is the word conveyed.

Knight Spencer's Anthropo-Telegraph consists of two circular disks, of basket work, about eighteen inches in diameter, painted white, with a black ball in the centre of each. These are held by the person to make the signals, one in each hand. By displaying one or both, according to the signal intended at different angles; all necessary information, orders, and commands, may be conveyed by the commanders of armies to every part of their line, &c. This invention was rewarded by the Society for the Encouragement of Arts and Manufactures, with their silver medal, and is described at lengh in their Transactions for 1809, but no general officer has yet reduced it to practice.

The Camp-Telegraph, consists, for day signals, of three flexible balls mounted on staves about ten or twelve feet in height, one of which is distinguished by being double, and used as a centre point; the other two are carried to different distances, to the right or left of the centre point, according to the intended signal. This invention is both simple and portable, the whole apparatus not being more cumbrous than three halberts, or pikes. Questions have been asked by it, and answers obtained, frequently, at the distance of six miles within the space of three minutes. But the most important part of the invention is, that by which night signals are made. It consists of lights, or lanthorns, constructed with hollow lenses, filled with different coloured fluids, the effects of which are such, that communications both on shore and afloat, may be made, with more certainty, than any hitherto made by day.

Lieutenant Spratt, of the Royal Navy, obtained in 1809, from the Society of Arts, &c. their silver medal for his invention of the homograph, or a method of making signals by sea or land, by means of a white pocket handkerchief held in different positions with the body. It is described at length in the Transactions of the Society, vol. xxvii. p. 163.

Various other telegraphs have been invented by Hooke, Garnett, and Pasley.

To this Class belongs also Coutel's Balloon at the Battle of Fleuris.

361. Coutel, Captain of the Aeronautic corps, was the man who ascended with the Entreprenant Balloon, on the 26th of June, 1794, and who conducted the wonderful and important service of re

connoitering the hostile armies at the battle of Fleuris, accompanied by an Adjutant and a General, He ascended twice on that day, to observe, from an elevation of 440 yards, the position and maneuvres of the enemy.

On each occasion, he remained four hours in the air, and by means of preconcerted signals with flags, carried on a correspondence with General Jourdan, the Commander of the French army. His intended ascent had been made known to the enemy, who, at the moment the balloon began to take its flight, opened the fire of a battery against the aeronauts. The first volley was directed too low: one ball, however, passed between the balloon and the car, and so near to the former, that Coutel imagined it had struck it. When the subsequent discharges were made, the balloon had already reached such a degree of altitude, as to be beyond the reach of cannon-shot, and the aeronauts saw the balls flying beneath the car. Arrived at their intended height, the ob servers, remote from danger, and undisturbed, viewed all the evolutions of the enemy; and from the peaceful regions of the air, commanded a distinct and comprehensive prospect of two formidable armies engaged in the work of death. Colossus of Rhodes, was rather a Light-house, than a Telegraph; but there is reason to suppose it answered both purposes.

362. This enormous building has justly been classed among the wonders of ancient architecture. It was a vast structure of brass or statuary metal, erected in honour of Apollo or the sun, the tutelary god of the island; and answered the purpose of a lighthouse to the mariners, who were sailing to or from the island in the night time. The light proceeded from an immense fire contained in a brass vase held in the uplifted right hand of the Colossus.

Its stride was fifty feet asunder, each foot being placed on a rock at this distance from each other, and which bounded the entrance into the haven: its height, according to Pliny, was not less than a hundred and five feet, or seventy cubits; and hence ships of considerable burden were capable of sailing between its legs. It is said to have been erected by the Rhodians with the money produced by the sale of the engines

of war which Demetrius Polioreetes employed in fruitlessly besieging the city for a twelvemonth, and which he gave to them upon his reconciliation. Pliny affirms that it was commenced by Chares of Lindus, a disciple of Lysippus, and finished upon his death by Laches of the same town. It was thrown down by an earthquake sixty years after its completion. As a proof of the immensity of this brazen statue, it is only necessary to observe, that the fingers of it were as large as the body of a full grown man, and the thumb so thick, that few men with outstretched arms were able to encompass it.

CHAPTER XVI.

PHYSICS.

SECTION I.

GENERAL PROPERTIES OF MATTER.

363. EVERY being or substance that exists is made up of matter, whose properties we can investigate, though of itself we can know nothing. Now it is the property of some kinds of matter to act upon our senses immediately, of others, only by the perceptible effects they produce upon other bodies. And we do therefore arrange under the former all sorts of matter as are capable of being seen, as wood, stone, &c.; and under the latter, such species of matter as prove their existence only by their effects upon other bodies, as the atmospheric air, gasses, &c.

364. The properties of matter are solidity, or impenetrability, divisibility, mobility, and inertia. SOLIDITY is that property by which two bodies cannot occupy the same place at the same time.

If a piece of wood, or stone, occupy a certain space, before you can put another body into that space, you must first