instructions relative to the management of the machine given by the Captain in "The Miner's Friend," is too liberal and honest an appeal to experiment for mere plagiarism, if the construction of an engine from so enigmatical a description could be so branded. The Doctor, however, accuses him of having bought up and burnt all the Worcester pamphlets. Such an act might have been prompted by the interest depending on the patent; but it is not proved; and in any case, as Lord Orford said, would have been an amazing piece of folly. He also relates that the Captain invented a story, as the first hint of his invention; which story, however, does not appear in "The Miner's Friend." It seems that Savery, having emptied a Florence flask, had thrown it on the fire, when perceiving the little wine left in it had filled the bottle with steam, he took it by the neck, and plunging its mouth under the surface of the water in which he was washing his hands, the water was immediately driven up by the pressure of the air. "Now," exclaims Desaguliers," he never made such an experiment then, nor designedly afterwards." To prove this rash assertion, he then details, that on his making the trial, the pressure of the atmosphere was so strong as to beat the flask out of his hand, and throw it against the ceiling. This is a most unwarrantable and unphilosophical conclusion for a man of science and probity;-the same quantity and quality of wine, as well as the same thickness of glass, and the same heat, would be required for fair comparison; and the Doctor's atmospherical pressure is not the least extraordinary part of the experiment. Nor was this the only attack on the Captain;-he was accused by the French of having merely improved upon the schemes of Papin and Amontons; we will therefore briefly refer to what was passing in France.

About the year 1682, that dexterous hypocrite, Sir Samuel Moreland, being at St. Germains, exhibited a project for raising water by steam to the French king. There is no record of the experiment; but a manuscript in the Harleian Collection, in the British Museum, proves that he only followed the Marquis of Worcester. At the same time, Dr. Papin, in trying to dissolve bones in a digester by steam of a very high pressure and temperature, is said to have introduced the simple but invaluable accompaniment of the steam-engine, the safety-valve, and thereby contributed to mature a machine which must otherwise have been abandoned. There is also an inference, though he never followed up the idea by actual experiment, that he invented the well-known atmospheric steam-engine. With these admissions in his favour, we are constrained to add, that the attempts of Dr. Papin to employ the force of steam are scarcely entitled to notice, either on the score of originality, merit, or precedency; for his principal work, in which he concedes priority to Savery, was not published till 1707. And M. Amontons has still smaller claim: his invention consisted of a firewheel for the production of circular motion, and was announced in 1699; but as the motion of this wheel was to be produced by the alternate dilatation and contracting of air, and not of the steam of

* Dr. Desaguliers attempted an amendment on Savery's engine; but his sugges. tion was not adopted, as it caused the death of the manager. Dr. Harris asserted that Savery's was not to be hurt "but by stupidity and negligence."

boiling water, it has nothing in common with the Captain's machine, except that the first cause of motion is fire.

A few years after the publication of the "Miner's Friend," the wellknown Mr. Newcomen, an ironmonger, together with Cawley, a glazier of Dartmouth, conceived the idea of improving upon Savery's engine; but their exertions terminated in the adoption of a new principle, of memorable consequence in the history of the invention. It consisted in abandoning the force of expansion, and employing only the condensation of steam to obtain a vacuum, and thus cause the pressure of the atmosphere-which was rendered effective in a very powerful degreeto act, unbalanced, upon a piston fitted into a cylinder; and as the force was therefore exerted on a moveable piston, the engine was capable of being applied to give motion to pumps and machines, whereas its predecessors were confined to the raising of water. This was less a matter of original discovery than a judicious combination of the inventions of others, for it consisted of Savery's condensation with Otto Guericke's exhausted cylinder. Savery hence laid his claim to a participation in the firm, and became, in consequence, associated in the patent obtained in 1705; and, in strict justice, that of Humphrey Potter-the boy who, to gain time for play, contrived tackles to make the machine work of itself-might have been afterwards added. From the union of principles in this new engine, a reciprocating motion was obtained, which was applied to the working of a forcing-pump, by the intervention of a great beam, suspended on gudgeons at the middle, and swinging like the beam of a balance. A rod from the centre of the piston was attached to one end of this beam by a short chain; and to the other end, the rod of the forcing-pump was similarly connected; every time, therefore, that the piston sunk in the cylinder, the rod of the pump which extracted the water from the mine, was drawn up; and as this end was purposely made heavier than the piston end, the piston rose when the steam was let in under it, although this steam might possess so little elasticity as only to be just a counterpoise to the weight of the atmosphere.

(To be concluded in our next.)

U. S. JOURN., No. 55, JUNE, 1833.

P

NARRATIVE OF THE CAPTURE OF THE DIAMOND ROCK, effected BY SIR SAMUEL HOOD, IN THE CENTAUR.

BY CAPTAIN BOSWALL, R.N.

AFTER the surrender of the Dutch colonies of Demerara and Berbice, in September, 1803, the Centaur, 74, Commodore Sir Samuel Hood, and Captain Sir Murray Maxwell, proceeded off the island of Martinique, for the purpose of blockading Ports Royal and St. Pierre, the two principal harbours on the west side of the island, to intercept any man-of-war, or vessels coming from France with stores or provisions for the garrison, of which our commodore had intelligence, by the capture, a few days before, of a French packet direct from Brest.

Having at this time very few men-of-war on the Barbadoes station, and those employed with the troops under General Greenfield on the before-mentioned services, the commodore in the Centaur undertook this important service of preventing supplies being thrown into Martinique, which was very effectually done for a short time, by the surest of tests to us on board—a few good captures. But powerful as our good ship was in men, guns, and swift in the breeze, we felt it no easy service for a single man-of-war to keep such an extended line of station from the Diamond to St. Pierre, so as to command the north and south passages round the island, as the prevailing trade-winds and strong currents often, during the night, and at other times, forced the ship so far to leeward of her proper station, that it occasioned us many an anxious chase after suspicious vessels, when descried within blockading limits.

We were not, however, long without a consort; for on the 2d of December, the Sophie, a French privateer, was taken by us, after an interesting chase of twenty-four hours. Sir Samuel Hood immediately put her into commission as a tender to the ship; the command of this schooner was given to Lieut. William Donett, and he was sent off the Diamond to keep a good look-out to windward, and to signal the approach of all vessels from that quarter, or attempting to pass between the rock and the mainland of Martinique.

While Mr. Donett was engaged on this service, he made frequent trips to the Diamond, for the object of procuring food for his stock, and found an abundance of thick, broad-leaved grass, well adapted for making straw hats for the seamen, which soon became a matter of some importance to them, as the schooner's crew had many orders from the ship for a supply. There was also growing on the rock, and almost covered it, an excellent substitute for spinach, called by the natives calallo; it is much the shape of the large common dock-leaf, and turned out a most useful vegetable to our people, as they had been long on salt beef; and the calallo, when boiled in large quantities and served out daily, put a stop to a heavy sick-list of scurvy cases.

The Diamond Rock now became a favourite spot, as the schooner had brought us so many good things; and I remember, when cruising on our usual station off Point Solomon, the schooner joined us. Mr. Donett came on board, when Sir Samuel then determined to take possession of the Diamond, fortify it, and to put it upon the establishment of a sloop of war. Next day, blacksmiths and carpenters were set to work, making intrenching tools, hand-barrows, &c., and the seamen to

make and prepare the necessary purchases. All in about a week was ready, as far as the resources on board the ship would admit; and a working party of fifty seamen and twenty-five marines, under the orders of Lieutenant Andrew Maurice, with fourteen days' provisions, were landed on the Diamond Rock. As the party was to keep the launch completely armed with her 24-pounder carronade, she was secured at the only landing-place, and the gun mounted on a projecting point, commanding this little cove. Immediately opposite the landing-place a very large cave was discovered, in which the forges were erected, and the carpenters and other artificers established their workshops; indeed it was so capacious, that it contained the whole party and material for the first night. The interior of this cave, generally with the whole rock, being grey limestone, was very dry. From the roof were suspended numerous stalactites, which made a most brilliant appearance when the forge and other lights were burning; added to which, the mirth and fun of the party at getting on shore after long confinement on board, and our very novel employment of fitting out such a nondescript vessel as his Majesty's sloop the Diamond Rock, made this evening pass off very cheerfully; and at the next dawn our party entered most zealously into the various duties they had to do, so very different from what they had lately been accustomed to.

The low flat ground, as seen in the wood-cut (p. 213), was soon cleared of its long grass and wild spinach ; and a number of small dry caves and openings at the base of the rock were selected by the seamen for suspending their hammocks, and forming themselves into messes, while the officers were in tents, pitched on the flattish part of the ground, containing about three quarters of an acre. There were also two other caves of large dimensions, which became of importance to the safety of the rock, as well as conducive to the health of the squadron cruising amongst the French islands. It was armed with a 32-pounder carronade; and here was afterwards executed the grand magazine called "Hood's Battery." It is about half way up the rock, (see wood-cut,) at least 360 feet from the water-line. This gun was sent up traversing on the jack-stay, or rope, secured at the top of the cave and on the low ground, and the latter was always used afterwards, by attaching a large tub to it, to convey stores and provisions to the upper parts of the rock; and when taken away, in the event of an enemy getting possession of the guns on the low grounds, the upper ones being deemed impregnable as long as they had ammunition or provisions, which was the case when the French fleet attacked it. They landed and stormed the lower forts, covered by their ships, after a heavy loss. Unfortunately, when our sailors retreated to the upper guns, they had not sufficient ammunition and water, and were obliged to surrender.

The other cave, on the east side of the rock, was built up in front to the height of three stories, and converted into a most excellent and wellaired hospital, (where the sick and wounded were sent, instead of conyeying them to Barbadoes or Antigua,) amply supplied, after we left it, with a good medical staff, and every comfort for such an establishment.

About this time a serious accident happened to our tender, the Sophie, which caused the most sincere regret and sorrow from the officers and crew of the Centaur. From some cause or other, which we never could learn, the schooner blew up off Point Solomon, and only one seaman

saved, by a French fishing canoe.
The service lost, in my poor
Donett, a gallant and promising officer.

friend

As there was no water to be found on the rock, a large tank was constructed to receive the numerous rills falling from the upper ridges, accumulated by the heavy dews which always fall in this climate during Then followed the night, and continue between sunset and sunrise. erection of the one-gun battery, (a long 24-pounder, named after the Centaur,) to command the channel between the rock and the mainland of Martinique. During the progress of these works, the ship at last came to an anchor on the south and most perpendicular side of the Diamond Rock.

The first thing to be done was to secure the Centaur by her bowers and spare anchors, and to suspend the hand-masts and fire-booms in a horizontal direction from her larboard side towards the base of the rock; the end of the stream-cable, to serve as a jack-stay, was then sent up by a line from the party on the top of the rock, and well secured round a projecting part of it, about eighty or one hundred feet below the summit. The inner, or ship end of the cable, was rove through a purchase, (called a vial,) used in line-of-battle ships for increasing the mechanical power of the capstan when they cannot weigh their anchors in stiff or tenacious ground, and well secured within the midship port on the main-deck,, after having been rove sufficiently taut to bring the handmasts and fire-booms to bear a steady pressure against the rock. The long 24-pounder was then suspended in the sling attached to the vialblock, and with a gun-tackle purchase, (simply a single block at the gun-slings, and the double one lashed at the upper part of the rock, through which was rove a small five-inch hawser,) the word was given at the capstan to heave round; and to all the inspiring tunes the band could play, away marched the first gun up its tremendous and perilous journey of seven hundred feet from the level of the sea, and four hundred feet horizontally from the ship. The men at the capstan were relieved every hour; and commencing at half-past ten A.M., the gun was landed at the upper end of the stream-cable at five o'clock P.M., having been seven hours in heaving him up to the first landing-place, when the party on shore parbuckled him up to his berth on the top of the rock with three cheers.

This battery was named according to the various fancies of the sailors, who had never undertaken such an extraordinary piece of service in their lives.

The next day they began on board the ship earlier, and the second gun was got up about three P.M., by the same means as the first; but the men were nearly nine hours at the capstans, in consequence of the wind blowing very fresh this day, causing the recoil of the waves from the base of the rock to be so powerful, that the ship became unsteady, swinging the gun at such a fearful rate, that three times the end of the stream-cable was cast off from the ship, and the gun remained suspended from the rock. Indeed, they almost despaired on board of getting it up, but fortunately they did succeed, as the gun was scarcely landed, when one of the cables which held the ship was discovered severely cut by the rocks, and in danger of going adrift every moment, which, towards evening, took place, as the cable parted from the anchor, and obliged her to put to sea, leaving Lieutenant Maurice and his party to mount the guns in battery.