has attended the speculation of Mr. Rupp; but, at one time, Bonaparte contracted for all the timber which he could send to the Rhine, and thereby prevented at least a stagnation of the commodity.

There are seyeral scientific considerations connected with the facts now detailed, which seem to have puzzled Mr. Playfair not a little, and which, indeed, weighed with him so far as to make him refuse his consent to have his paper inserted in the Transactions of the Society, before whom it was read. The rapidity of the descent, 'so much greater than could possibly have been anticipated, is not he thought easily to be reconciled with the notions concerning friction, that are usually received even in the scientific world. It appears, however, that Professor Playfair was not familiarly acquainted with the most recent notions concerning friction entertained among practical engi

neers, and particularly with the fine experiments of the French • writer, Coulomb: and consequently, whilst reasoning on the subject,

hazarding his conjectures, and proposing his solutions, he was not aware that what appeared to him perfectly new, had been long received as established principles among men engaged in practical mechanics. It is pleasing, at the same time, to observe, that the inferences which the Professor draws from the facts before him, by means of mathematical reasoning, are substantially the same with those which experience has pointed out to less scientific persons; for the conclusions at which he has arrived, through a process of deep calculation, are found to coincide astonishingly well with the practical maxims of the ship-builder, when he launches a vessel from the slips, and with the operations of the engineer, in the movement of very heavy bodies on an inclined plane. In short, it seems to be now perfectly established, that heavy bodies when put in motion on an inclined plane, are relatively less retarded by friction than lighter ones are: and secondly, that friction, in all cases, is diminished in proportion as the velocity of the sliding is increased. What the precise ratio is at which the friction is lessened relatively to the augmented velocity is, we believe, a point not yet clearly determined; but in regard to the fact itself, so little doubt is now entertained, that we are only astonished Mr. Playfair should have esteemed the announcement of it as a novelty in mechanics.

It is very true, however, as the Professor remarks, that we have here a strong instance of the danger of concluding in the researches of mechanics, from experiments made on a small scale, in regard to what should be the practice when applying the result to a large scale. When our experiments lead to the knowledge of a fact and not of a principle, there is the utmost caution requisite in extending the conclusions beyond the limits by which the experiments have been confined. And this is particularly the case with the experiments on friction, where we know only facts and have no principle to guide us; that is, we have not been able to connect the facts with

any

of the known and measurable properties of bodies.

" That friction belongs to the cases in which great caution is necessary in extending the conclusions of experiments, is indeed most strongly evinced by the operations that have now been described; the result of which is such as could not have been anticipated from these experiments. The danger here, however, is quite of an opposite kind from that which commonly takes place in such instances. The experiments on the small scale, usually represent the thing as more easy than it is upon the great, and engage us in attempts that prove abortive, and

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are followed by disappointment and even ruin. In the present case, the experiments on the small scale represent the thing as more difficult than when tried on the great one it is found to be; and would lead us by an error the direct opposite of the last, to conclude things to be impracticable that may be carried into effect with ease. Had the ingenious inventor of the slide at Alpnach, been bet. ter acquainted with the received theories of friction, or the experiments on which they are founded, even those that are the best and on the greatest scale, such as those of another most skilful engineer, M. Coulomb, or had he placed more faith in them, he never would have attempted the great work, in which he has so eninently succeeded.”

It appears, however, in fact, that Mr. Rupp, the inventor of the slide at Alpnach, was much better acquainted than Professor Playfair with the received theories of friction, and in particular, we may be allowed to suppose, with the improved views derived from the ingenious experiments of Coulomb; and, moreover, that it was because he had faith in the received theories, so modified and confirmed, that he engaged in the immense enterprise which is likely to hand down his name to posterity, as one of the most enlightened engineers of the nineteenth century.

The volumes now given to the world as the works of Mr. Playfair, contain his “ Illustrations of the Huttonian Theory;" the “ Dissertation on Physical Science,” published in the Supplement to the Enclyclopædia Britannica; a variety of papers originally printed in the Transactions of the Royal Societies of London and Edinburgh; and, lastly, a selection from the articles which he contributed to the Edinburgh Review. The " Dissertation exhibiting a general View of Mathematical and Physical Science since the Revival of Letters in Europe,” is worthy of the author's name; but unfortunately, owing to his death before the materials could be finally prepared for the press, it remains in an unfinished state, and must for ever continue in the shape of a mere fragment.

One of the last things Mr. Playfair wrote, and with which he seems to have amused himself during part of the time he was confined with illness, is a Memoir relating to Naval Tactics, as improved by the late John Clerk of Eldin.

It is a singular incident in the history of human affairs, that a person who had never been at sea in his life, should have introduced into military seamanship the most important improvement which that difficult art has received in modern times. From his early youth, a fortunate instinct seems to have directed his mind to this line of study.

“I had,” says he, in a document referred to by Mr. Playfair, “acquired a strong passion for nautical affairs when a mere child. At ten years old, before I had seen a ship, or even the sea at a less distance than four or five miles, I formed an acquaintance at school with some boys who had come from a distant sea-port, who instructed me in the different parts of a ship, from a model which they had procured. I had afterwards frequent opportunities of seeing and examining ships at the neighbouring port of Leith, which increased my passion for the subject; and I was soon in possession of a number of models, many of them of my own construction, which I used to sail on a piece of water in my father's pleasure grounds, where there was also a boat with sails, which furnished me with much employment. I had studied Robinson Crusoe, and I read all the sea voyages I could procure.”

Upon the commencement of the American war, Mr. Clerk, who continued to pay the utmost attention to the subject of naval tactics, and derived all the knowledge he could possibly acquire from read

ing and conversation, and particularly from studying the details of the several actions which took place between the belligerents, saw more and more reason to suspect that there was something very erroneous in the method heretofore pursued by the British admirals, for bringing their fleets into battle.' He perceived, that while nothing could exceed the skill with which the ships individually were work. ed and maneuvred, the plan followed in bringing a whole fleet to meet the enemy was extremely uncertain and precarious: and, in a word, he was convinced from the conduct of our bravest and most skilful admirals, that an expedient for forcing their antagonists to fight, on equal terms, was an addition to the art of naval warfare that remained still to be discovered.

It had usually happened, that the British fleet was eager to engage, and that the enemy was unwilling to risk a general action; the object of our commanders, therefore, had almost always been to gain the weather gage, as it is called, of the enemy, or to place themselves to the windward of his fleet. When that fleet was drawn out in line, in the manner necessary for allowing every ship its share in the action, the British fleet bore down from the windward upon the enemy; who was so placed as to have his whole line, and also the broadside of each individual ship, nearly at right angles to the direction of the wind. In such circumstances, the British had usually adopted one of the two following methods, in order to make the attack. They either formed their fleet into a line parallel and directly opposite to that of the enemy, whence each ship bore down upon that which was immediately opposed to it; or, sailing on the tack' opposite to that on which the enemy stood, ran along parallel to their line, and within fighting distance, till the whole of the one line was abreast of the other, and each ship ready to engage her antagonist.

If the former of 'these methods was pursued, each ship on coming down had to sustain a destructive fire from the broadside of the one immediately opposed to her in the enemy's line, which she could only return very ineffectually from the few guns mounted in her bows. The rigging, consequently, which presented the best mark, when the ship was moving end on before the wind, was in general so dreadfully cut by the enemy's shot, that the vessel was always much disabled, and sometimes rendered totally unmanageable, before she arrived within fighting distance.

If the second method was pursued, the headmost ship had to endure the fire of the whole line before she arrived in her place; the next, the fire of all but one; the third had to sustain the broadsides of all but two, and so on; so that it was very improbable that any, except the sternmost ships, could reach their station in the line without having received material damage. This mode of fighting, it requires not to be observed, would give to the enemy who remained quietly on the defensive, a great advantage over the attacking squadron, and enabled him almost to a certainty to maim his antagonist's fleet, with very little loss to himself, or even to gain a victory without exposing to any great hazard either his men or his ships.

“Mr. Clerk had the merit of pointing out the evils now enumerated, in a manner most clear and demonstrative, and of describing a method by which the attack might be made, without incurring any of the disadvantages that have been mentioned, and almost with a certainty of success. As the evil arose from an enVOL. I. No. 3.-Museum.

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dearour to diffuse the force of the attack, if one may say so, over the whole sur, face of the line attacked; so the remedy consisted in concentrating the force of the attack, and in bringing it to bear with pmportionably greater energy on a single point, or a small portion of the enemy's line. For this purpose the admi. ral of the attacking and win lward squadron is supposed to come down, not in a line, but with his feet in divis.ons, so as to be able to support the particular divi. sion destined to break tirough the line of the enemy. The consequence must be, that if this attack is directed against the rear of the enemy, the ships ahead must either abandon those that are cut off, or mist double back either by tacking or wearing. Mr. Clerk shows, that if the enemy follow the first of these methods, and make his line either tack in succession or altogether, such a distance must be left between them and the three or four sternmost ships, that not only must these last be easily carried, but that several more must probably be thrown into such a situation, as to subject them almost unavoidably to the same fate. If the enemy attempt the same thing by wearing, his condition will be still worse. The feet by falling to leeward must not only desert the ships altogether, but must leave the sternmost of the wearing ships so much exposed, as to render it certain that they will be entirely cut ofl.”

There can be no doubt that the system proposed and explained by Mr. Clerk was entitled to the full merit of originality. In his work he has entered into a historical detail which tends to establish this point, and in which, from the most authentic documents, he traces the plans of most of our remarkable naval actions, from that of Admiral Matthews, off Toulon, in 1744, to that of Admiral Greaves, off the Chesapeake, in 1781. In most of these actions we find, though conducted by some of our ablest naval officers, that the British fleet being to windward, and by extending the line of battle so as to destroy the whole of the eneiny's line, which was of course, to leeward, was itself disabled, before the ships could reach a situation in which they could annoy their adversaries; while, on the other hand, the French perceiving the British ships in disorder, usually made sail, and after throwing in their whole fire, formed their line again to leeward, where they lay prepared for another attack, should their antagonists feel inclined to make it. In this way, campaign after campaign was frustrated, and baffled, and even defeated, that rare combination of skill and courage, which distinguishes the English seaman, and which was even then so conspicuous and successful in actions with single ships. The analysis and commentary which Mr. Clerk applies to these actions are very instructive to professional men, and form a scientific review of the naval history of Great Britain, which we should look for in vain in any of the treatises expressly written on that subject.

It was on the 12th of April, 1782, that the merits of Clerk's system were put to the trial and approved. The brave Rodney, who, like all able men, showed the utmost willingness to learn, even from a landsman, went to sea determined to avail himself of the new lights in his profession with which he had just been supplied. Before going out to take the command of the fleet in the West Indies, he said one day to Mr. Dundas, afterwards Lord Melville, “ There is one Clerk, a countryman of yours, who has taught us how to fight, and appears to know more of the matter than any of us. If ever I meet the French fleet I intend to try his way.” He did try it; and by his distinguished success set an example to succeeding admirals, which by bringing into full play the native strength and courage of British sailors, has swept from the ocean all the other navies of Europe, and secured for

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our countrymen an ascendancy in nautical warfare, that no nation, ancient or modern, has ever possessed.

Dupin, whose work on the naval force of Great Britain, we noticed in our April number, has given a brief account of Rodney's victory, as the first application of Clerk's principles, and appreciated fully the value of the system which was thereby so powerfully recommended to our admirals.

“ In the victory gained by Rodney over De Grasse,” says he, “the former having cut through the other's line in the centre, and our rear division having yielded to the combined attack of the enemy's whole fleet, the English doubled back upon that portion of the centre which our rear had abandoned. Then the French admiral, with the ships around him, pressed by a superior force, and caught between two fires, were compelled to surrender. This was the most decisive battle since that of La Hogue.”

Trafalgar, we may add, as Dupin himself allows, was a still more direct and brilliant exemplification of the same method of attack: and wonderful as that action was in every respect, there is nothing connected with it so surprising, as the stupid adherence of the French commander to his antiquated tactics. Whilst the centre was involved in inevitable destruction, from the combined onset of the whole British fleet, the wings remained inactive and immoveable. Ces ailes sont en ligne, et cela leur suffit : elles attendent donc avec une effrayante impassibilité que leur contre soit detruit ; il l'est enfin. Alors oubli

. ant leur pieux respect pour l'ordre sacré de la ligne, ellis ne songent plus qu'à la retruite.

That Lord Nelson did not disdain to study the work of a mere theorist, when completing his professional accomplishments, and even in arranging his plan of battle, is evident from the circumstance, mentioned here by Mr. Playfair, that in the very body of the instructions issued by his Lordship before the conflict at Trafalgar, there are several sentences entirely taken from the Naval Tactics. These instructions were transmitted to Mr. Clerk by Sir Philip Durham, one of the commanders in that memorable action, accompanied with the following note, which shows in what light his improvements were regarded by those who were the best able to decide upon their merits.

“ Captain Durham, sensible of the many advantages which have accrued to the British nation, from the publication of Mr. Clerk's Naval Tactics, and particularly from that part of them which recommends breaking through the enemy's line, begs to offer him the enclosed form of battle, which was most punctually attended to in the brilliant and glorious action of the 21st of October. "Mr. Clerk will perceive with pleasure, that it is completely according to his own notions, and it is now sent as a token of respect from Captain Durham to one who has merited so highly of his country. H. M. S. off Cadiz, 29th of October, 1805."

Mr. Playfair informs us that he had before him, whilst writing his remarks, a copy of the first part of the Naval Tactics, with notes on the margin by Lord Rodney himself, which had been communicated by the admiral to the late General Clerk, by whom it was deposited in the family library at Penicuich. These notes, it is said, are full of remarks on the justness of Mr. Clerk's views, and on the instances wherein his own conduct had been in strict conformity with those views. Rodney, (at that time Sir George) even condescends to answer some questions which Mr. Clerk had put in regard to the acton off Martinique in the year 1780. The first signal of the Admi