HAVING considered sea cause of the saline quality of the water, we now enquire what is the use of it. Some have said there are two uses, to keep it from corruption, and to give it greater strength to support the ships that sail upon it. But we know that fresh water is equally fit for every purpose of navigation, as salt; nor does it appear from experience, that salt water resists putridity more than fresh. Let any person take an equal quantity of each in separate vessels, either open or closely stopped, and put it by in the shade, or in the sun, and he will find upon trial that the sea water will grow putrid sooner than the fresh. Perhaps, we do not as yet fully know the uses of the ocean being salt; but we certainly know that motion contributes more to prevent corruption in the sea, than salt does.

The ocean, besides its tides, has its currents, which circulate its contents round the globe; and these may be said to be the great agents that keep it sweet and wholesome. Its saltness alone would by no means answer that purpose: and some have even supposed, that the various substances with which it is mixed, rather tend to promote putressence than impede it. Sir Robert Hawkins, one of our most enlightened ancient navigators, gives the following account of a calm, in which the sea, continuing for some time without motion, began to assume a very formidable appearance. "Were it not," says he, " for the moving of the sea, by the force of winds, tides, and currents, it would corrupt all the world. The experiment of this I saw in the year 1590, lying with a fleet about the islands of the Azores, almost six months; the greatest part of which time we were becalmed. Upon which all the sea VOL. IV.

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become so replenished with several sorts of jellies, and forms of s erpents, adders, and snakes, as seemed wonderful: some green, some black, some yellow, some white, some of divers colours: and many of them had life; and some there were a yard and a half, and even two yards long; whic h had I not seen, I could hardly have believed. And hereof are witnesses

all the company of the ships which were then present: so that hardly a man could dip a bucket of water clear of some corruption. In which voyage, towards the end thereof, many of every ship fell sick, and began to die apace. But the speedy passage into our own country, was a remedy to the crazed, and a preservative for those that were not touched."

This shews sufficiently how little the saltness of the sea is capable of preserving its waters from putrefaction: but to put the matter beyond ail doubt, Mr. Boyle kept a quantity of sea water, taken up in the English channel, for some time barrelled up; and in the space of a few weeks, it began to acquire a fœtid smell. He was also assured, by one of his acquaintance, who was becalmed for some time in the Indian ocean, that the water, for want of motion, began to stink: and that had it continued much longer, the stench would probably have poisoned the whole crew. It is the motion, therefore, and not the saltness of the sea, that preserves it in its present state of salubrity.

There are some advantages, however, which are derived from the saltness of the sea. Its waters, being evaporated, furnish that salt which is used for domestic purposes; and although in some places it is made from springs, and in others dug out of mines, yet the greatest quantity is made only from the sea. That which is called bay-salt-from its coming to us from the Bay of Biscay-is of a stronger kind, made by evaporation in the sun that called common salt, is made by evaporation in pans over the fire, and is of a quality much inferior to the former.

We have before observed that it requires a much greater degree of cold to freeze salt water than fresh, and this is perhaps the greatest benefit which we derive from the saline quality of the ocean. For while rivers and pools are converted into ice, or, at least, covered with it, the sea is in most places, open, and always fit for navigation, When at land, the stores of nature are all locked up from us by the cold, the sea is still accessible with its riches, and patient of the hand of industry.

But it must not be supposed, because in our temperate climate we never see the sea frozen, that it is in the same manner open in every part of it. Mariners inform us that in the polar regions it is embarrassed with mountains, and moving sheets of ice, that often render it impassable.

These treinendous floats are of different magnitudes; sometimes rising more than a thousand feet above the surface of the water; sometimes diffused into plains of above two hundred leagues in length; and in many parts sixty or eighty broad. They are usually divided by fissures ; one piece following another so close, that a person may step from one

to the other.

Sometimes mountains are seen rising amidst these plains, and presenting the appearance of a variegated landscape, with hills and walleys, cities, churches, castles, and towers.

These are appearances in which all naturalists are agreed; but the great contest is respecting their formation. Buffon asserts that they are formed from fresh water alone; which congealing at the mouths of great rivers, accumulate those huge masses that disturb navigation. But this great naturalist seems not to have been aware that there are two sorts of ice floating in these seas; the flat ice, and the mountain ice : the one formed of sea water; the other of fresh.

The flat, or driving ice, is composed of sea water: which upon dissolution, is found to be salt: and is readily distinguished from the mountain or fresh water-ice, by its whiteness, and want of transparency. This ice is much more terrible to mariners than that which rises up in lumps; a ship can easily avoid the one, as it is seen at a distance; but it often gets in among the other, which, sometimes closing, crushes it to pieces. This, which manifestly has a different origin from the fresh water ice, may perhaps have been produced in the Icy Sea, beneath the pole.

The mountain ice is different in every respect, being formed of fresh water, and appearing hard and transparent; it is generally of a pale green colour, though some pieces are of a beautiful sky blue; many large masses, also, appear grey; and some black. If examined more nearly, they are found to be incorporated with earth, stones, and brush-wood, washed from the shore. On these also, are sometimes found, not only earth, but birds nests with eggs, at several hundred miles distance from land. The generality of these, though almost totally fresh, have nevertheless, a thick crust of salt water frozen upon them, probably from the power that ice has sometimes to produce ice.

Such mountains as are here described, are most usually seen at spring time, and after a violent storm, driving out to sea, where they at first terrify the mariner, and are soon after dashed to pieces by the continual washing of the waves; or driven into the warmer regions of the south, there to be melted away. They sometimes, however, strike back upon their native shores, where they seem to take root at the feet of the mountains; and rise sometimes higher than the mountains themselves. They have been seen of a blue colour, full of clefts and cavities made by the rain, and crowned with snow, which alternately thawing and freezing every year, augmented their size. These, composed of materials more solid than those which drive at sea, present a variety of agreeable figures to the eye, that, with a little help from fancy, assume the appearance of trees in blossom; the inside of churches, with arches, pillars, aud windows; and the blue coloured rays darting from within, often presents the the resemblance of a glory.

If we inquire into the origin and formation of these, which, as we see are very different from the former, we shall find a very satisfactory account of them in Krantz's History of Greenland.

"These mountains of ice, (says he) are not salt, like the sea water, but sweet, and therefore can be no where formed except on the mountains, in rivers, in caverns, and against the hills near the sea shore. The mountains of Greenland are so high that the snow which falls upon them, particularly in the north side, is, in one night's time, converted into ice they also contain clefts and cavities, where the sun seldom or never injects his rays: besides these, there are projections, or landing places, on the declivities of the steepest hills, where the rain and snow waters lodge, and quickly congeal.

When now the accumulated flakes of snow slide down, or fall with the rain from the eminences above, on those prominences, or, when here and there a mountain-spring comes rolling down to such a landing place, where the ice has already seated itself, they all freeze, and add their tribute to it. This by degrees waxes to a body of ice, that can no more he overpowered by the sun; and which, though it may indeed, at certain seasons, diminish by a thaw, yet upon the whole, through annual acquisitions, it assumes an annual growth.

Such a body of ice is often prominent far over the mountains. It does not inelt at the top, but underneath; and also cracks into many larger. or smaller clefts, whence the thawed water trickles out. By this it becomes at last so weak, that being overloaded with its own ponderous bulk, it breaks loose, and tumbles down the rocks with a terrible crash. Where it happens to overhang a precipice on the shore, it plunges into the deep with a shock like thunder; and with such an agitation of the water, as will overset a boat at some distance, as many a poor Greenlander has fatally experienced."

Thus are these amazing ice mountains launched forth to sea, and found floating in the northern regions. It is partly owing to these dangerous masses, and partly to the field ice, that the polar regions are inaccessible to our navigators.

In the midst of such tremendous masses of ice many navigators have been arrested and frozen to death. In this manner the brave Sir Hugh Willoughby perished with all his crew in 1553. And in the year 1773. Captain Phipps-now lord Mulgrave-was caught in the ice, and very nearly met the same unhappy fate. The reader may see the account at large in Phipps's Voyage to the North Pole. The scene, as there described, divested of the horror from the eventful expectation of change, was the most beautiful and picturesque imaginable-Two large ships becalmed in a vast bason, surrounded on all sides by islands of various forms; the weather clear; the circumambient ice tinted with a thousand colours; many finepools of water appeared upon the flats crystalline with the young ice; the small space of sea, in which they were confined, perfectly smooth. After fruitless attempts to force a passage, their limits were perpetually contracted by its closing upon them; till at last each vessel became immovably fixed. The smooth extent of surface betwixt the islands was soon lost; the pressure of the pieces of ice, by the violence of the swell, caused them to pack; fragment rose upon fragment, till they were in many places higher than the mainyard. The movements of the ship were

tremendous and involuntary, in conjunction with the surrounding ice, actuated by the currents.

The water shoaled to fourteen fathoms. The grounding of the ice or of the ships would have been equally fatal. The force of the ice might have crushed them to atoms, or have lifted them out of the water and overset them, or have left them suspended on the summits of the pieces of ice at a tremendous height, exposed to the fury of the winds, or to the risk of being da hed to pieces by the failure of their frozen dock. An attempt was made to cut a passage through the ice; after a perseverance worthy of British seamen, it proved fruitless. The commander, at all times master of himself, directed the boats to be made ready to be hauled over the ice, till they arrived at navigable water-a task alone of seven days unremitting labour-and in them to make their voyage to England. The boats were drawn progressively three whole days. At length a wind sprung up, and the ice separated sufficiently to yield to the pressure of the full-sailed ships, which after labouring long against the ice, at length got safe out into clear water.

The collision of the great fields of ice, in high latitudes, is often attended with a noise that, for a time, takes away the sense of hearing any thing else; while the smaller fields produce a grinding noise of unspeakable horror. These are some of the wonders of Jehovah in the great deep. Wonders which ancient navigators had no conception of. It is in modern days only that the ocean has been traversed both in the equatorial and polar regions, and its productions and appearances in both, have been accurately described.

These fields and islands of ice, though formed only in the high regions near the poles, are nevertheless, by currents and storms, driven far into milder latitudes. Thus the country of Iceland is frequently visited with them, though none are formed near that island, unless great quantities are driven upon its shores first. The ice comes on here by degrees, always with an easterly wind, and frequently in such quantities as to fill up all the gulphs on the north-west side of the island, and even to cover the sea as far as the eye can reach. Sometimes, remaining long upon the coast, it does incredible damage. Mountains of it have been found here sixty fathoms in height, and sometimes these enormous masses have been grounded in shoal water, and have continued for

years before they have been dissolved, chilling the atmosphere with their influence for a great way round. It is said, that when many such bulky and lofty ice-masses are floating together, the wood which is often found drifting between them, is so much chafed, and pressed with such violence together, that it sometimes takes fire: which circumstance has occasioned fabulous accounts of the ice being in flames.

In the years 1753 and 1754, Iceland was visited with vast shoals of ice, which occasioned such coldness of the atmosphere, that horses and sheep dropped down dead by reason of it; vegetation was every where stopped by it, so that some horses were observed to feed upon dead cattle, and sheep to eat each others wool through hunger.

Besides these calamities, in this country a great number of bears arrive with the ice, which often make great ravages among the sheep.