be more astonishing and marvellous than that of navigation, in the state in which it is at present; an art which doubtless affords one of the most certain irrefragable proofs of the amazing powers of the human understanding. This cannot be made more evident than when, taking a retrospective view of the tottering, inartificial craft to which navigation owes its origin, we compare it to a noble and majestic edifice, containing 1000 men, together with their provisions, drink, furniture, wearing-apparel, and other necessaries for many months, beside 100 pieces of heavy ordnance; and bearing all this vast apparatus safely, and as it were on the wings of the wind, across immense seas to the most distant shores. The following example may serve for the present to delineate at full length, as it were, the idea above alluded to. But first I must premise that a huge, unwieldy log of wood, with the greatest difficulty, and in the most uncouth manner, hollowed out in the inside, and somewhat pointed at both ends, and in this guise set on a river for the purpose of transporting two or three persons belonging to one and the same family across a piece of water a few feet deep, by the assistance of a pole pushed against the ground, cannot with any propriety be considered as the image of navigation in its first and earliest stage. For it seems evident to me, that people in the beginning only took three or four trunks of trees, and fastened them together, and then, by means of this kind of raft, got across such waters as were too deep for them to ford over, and across which they could not well swim with their children, and various kinds of goods which they might wish to preserve from being wet. The canoe, however, is a specimen of the art in a more advanced state, as this kind of craft is capable of having direction given to it, and even of so capital an improvement as that of having a sail added to it. For this reason I choose this vehicle for a standard, in preference to a mere raft, to which, imperfect as it is, it is so much superior. Let us, then, compare this with a large majestic floating edifice, the result of the ingenuity and united labour of many hundreds of hands, and composed of a great number of well-proportioned pieces, nicely fastened together by means of iron nails and bolts; and rendered so tight with tow and pitch, that no water can penetrate into it. Now, in order to give motion and direction to this enormous machine, some astonishingly lofty pieces of timber have been fixed upright in it, and so many moveable cross pieces have been added to it, together with such a variety of pieces of strong linen cloth, for the purpose of catching the wind, and of receiving its impulse and propelling power, that the number of them amounts to upward of thirty. For changing the direction of these yards and sails, according to particular circumstaces, it has been also requisite to add a vast quantity of cordage and tackling; and, nevertheless, even all this would not be sufficient for the perfect direction and government of the vessel, if there were not fastened to the hinder part of it, by means of hinges and hooks, a moveable piece of wood, very small indeed in proportion to the whole machine, but the least inclination of which to either side is sufficient to give immediately a different direction to this enormous large mass, and that even in a storm, so that two men may direct and govern this swimming island with the same or with greater ease than a single man can do a boat. But if, besides, we consider that, in a vessel like this, not a single piece is put in at random, but that every part of it has its determined measure and proportion, and is fixed precisely in that place which is the most advantageous for it; that, throughout every part of it, there is distributed an astonishing quantity of blocks, stays, and pulleys, for the purpose of diminishing the friction, and of accelerating the motion of these parts; that even the bellying and vaulted part of the fabric, together with its sharp termination underneath, are proportioned according to the nicest calculations, and the most accurately determined rules; that the length and the thickness of the masts, the size of the booms and yards, the length, width, and strength of the sails and tackling, are all in due proportion to one another, according to certain rules founded upon the principles of motion: when we consider all this, I say, our admiration increases more and more at this great masterpiece of human power and understanding. Still, however, there are wanting a few traits to complete this description. A man in health consumes, in the space of twenty-four hours, about eight pounds of victuals and drink: consequently, 8000lb. of provisions are required daily in such a ship. Now let us suppose her to be fitted out for three months only, and we shall find that she must be laden with 720,000lb. of provisions. A large forty-two pounder weighs about 6100lb. if made of brass, and about 5500lb. if of iron; and generally there are twenty-eight or thirty of these on board a ship of 100 guns, the weight of which, exclusive of that of their carriages, amounts to 183,000lb. On the second deck thirty twenty-four pounders, each of which weighs about 51001b. and therefore all together, 153,000lb. and the weight of the twenty-six or twenty-eight twelvepounders on the lower deck amounts to about 75,400lb. that of the fourteen six-pounders on the upper deck to about 26,600lb. and beside that, on the round tops, there are even three-pounders and swivels. Now, if to this we add, that the complete charge of a forty-two pounder weighs about 64lb. and that at least upward of 100 charges are required for each gun, we shall find this to amount nearly to the same weight as the guns themselves. In addition to this, we must reflect, that every ship must have, by way of providing against exigencies, at least another set of sails, cables, cordage, and tacklings, which altogether amount to a considerable weight. The stores, likewise, consisting of planks, pitch, and tow; the chests belonging to the officers and sailors; the surgeon's stores, and various other articles requisite on a long voyage; as also the small arms, bayonets, swords, and pistols, are no inconsiderable load; to which we must finally add the weight of the crew, which is not very trifling; so that one of these large ships carries at least 2162 tons burden, or 4,324,000lb. and at the same time is steered and governed with as much ease as the smallest boat. Now, the consideration of these circumstances alone is sufficient to excite the most serious reflections in a contemplative mind; and yet, if such a ship sailed along the coast only, and never lost sight of the shore, as the navigators of old used to do, we might still be tempted to look upon navigation as an easy and trifling business. But the finding the straightest and shortest way over an ocean of more than 60 or 80 degrees in longitude, and 30 or 40 in latitude; or across a track from 4000 to 6000 miles in extent, by day or by night, in fair weather or in foul, as well when the sky is overcast as when it is clear, and often with no other guide than the compass, and the being able to determine the true position of the ship at sea by the height of the sun, though this latter be enveloped in clouds, or to direct its course by the moon and stars with such exactness and precision as not to make a mistake of the value of half a degree or 30 miles; this at least shows the progress and great perfection of an art practised by a set of people, of whose understand ings many conceited and supercilious landmen have but a mean opinion, and whose plain and simple manners they frequently take the liberty of turning into ridicule. "A violent storm of wind will make us tremble with fear, even in a strong well-built house, and in the midst of a populous city; yet we have seldom, or never either seen or experienced the vast power of the enraged waves, when beat about by the winds, and dashed against each other till they seem transformed into froth and vapour, and the whole surface of the ocean presents to the eye a confused scene of immense watery mountains and bottomless precipices; and yet on such a sea as this the true seaman, provided he has but a good ship, rides with calm and unshaken courage, and thinks himself as safe in the midst of the ocean as in the best fortified castle.' No. LVII. ON THE NATURE OF THE TIDES. Alternate tides in sacred order run. BLACKMORE. The ebbs of tides, and their mysterious flow, DRYDEN. THE tides of the sea have ever been considered among the most wonderful phenomena in nature. The conjectures of the most ancient philosophers concerning them were equally various, visionary, and wild. Some of them considered the tides as ebullitions occasioned by subterraneous fires, or as |