thus continues: 'It had been long ago asserted by Macrobius, that sea water was never frozen, but that the ice found at sea proceeded from the freezing of the fresh water spread over its surface by the influx of rivers. And in modern times, the opinion, concerning the freezing of sea water, seems to have been admitted with great caution, by our most experienced navigators. They were aware, indeed, that the Baltic and other large seas were frequently frozen quite over, but they appear to have thought, that falls of snow laid a sufficient foundation for the production of that event, without its being at all necessary for the sea water to freeze.' I cannot conceive that there was any great occasion for this cautious mode of expression, since it had been observed, above a hundred years ago, that not only sea water, but water containing double the proportion of salt commonly found in our sea water, and more than is contained in the sea water of any climate, might be frozen by the cold prevailing in our atmosphere'."

A very eminent naturalist, who admits the congelation of sea water, has presented us with a very striking description of the wonderful phenomena which the mountains of ice exhibit in these regions of desolation. But as I have already availed myself of this description in my paper On Winter in the Polar Regions, I need not repeat it here.

The tides, the saltness of the sea, and mountains of ice, which I have thus described, are not the only phenomena observable in the wonderful world of waters. But I cannot, in this paper, enter into the discussion of any other.

1 Cook's Voyage, vol. ii. page 242.

2 No. IV.

No. LX.

CONCLUSION OF REFLECTIONS ON THE

OCEAN.

They that go down to the sea in ships, that do business in great waters; these see the works of the Lord, and his won ders in the deep.

PSALMS.

There are yet hid greater things than these be, for we have seen but a few of his works. We may speak much, and yet come short; wherefore, in sum, He is all.

ECCLUS.

THE works of nature can excite sensations of pleasure, even in minds the least habituated to reflection. Such, however, are content with mere exterior beauty, and extend not their researches beyond the surfaces of things. The vast expanse of waters appears to them in two aspects only; as an object of dreadful sublimity in a storm, or of pleasing magnificence in a calm. But the Contemplative Philosopher extends his view far beyond the distant horizon, and far below the agitated surface. He considers the ocean, with the Son of Sirach, as the immense receptacle of wonders yet undiscovered, and of phenomena, which, perhaps, will continue ever unexplained.

There is one very curious phenomenon in the ocean, which has long exercised the sagacity of philosophers. This is the luminous appearance of its surface during the obscurity of the night. M. Bayon, surgeon-major at Cayenne, made a great number of experiments, at different seasons, in order to find out its true cause; and it always appeared to him, that these luminous points were produced by friction alone. Though he often made use of the best glasses, he could never perceive any insect;

and, therefore, he is inclined to think, that these luminous points are rather the effects of motion and friction than of animal bodies, as has been supposed by some philosophers'. But from the experiments and observations of many learned men on this subject, as far backward as Bacon and Boyle, it appears evident, that various causes, both jointly and separately, produce this phenomenon. The experiments of Mr. Canton3 prove, that the putrefaction of animal substances produces light and scintillation in the sea. A little white fish placed in sea-water rendered it luminous in the space of twenty-eight hours; and certain quantities of salt, and oil of hartshorn, are known to produce a similar effect in common water. On the other hand, it is certain, that there is in the sea a prodigious quantity of shining insects or animalcules, which contribute to this phenomenon. M. Dagelet, a French astronomer, who returned from Terra Australis in 1774, brought with him several kinds of worms, which shine in water, when it is set in motion; and M. Rigaud affirms, that the luminous surface of the sea, from Brest to the Antilles, contains an immense quantity of little, round, shining polypi, of about a quarter of a line in diameter. Other learned men, who acknowledge the existence of these luminous animals, cannot, however, be persuaded to consider them as the cause of all that light and scintillation which appear on the surface of the ocean. They think that some substance of the phosphorus kind,

Memoires pour servir à l'histoire de Cayenne et de la Guienne Française.

2 Particularly Ozanum, in his treatise concerning Phosphori; Bartholin, in his Dissert. de Luce Animalium; Donati, in his History of the Adriatic Sea; Nollet, in the Memoirs of the Royal Academy of Sciences for 1750; and Vianelli, in his Nuove Scoperte intorno le Luci nottorni dell' Aqua Marina.

3 Philos. Trans. 1769.

4 Journal des Savans 1770.

arising from putrefaction, must be admitted as one of the causes of this phenomenon. M. Godehoue has published curious observations on a kind of fish, called in French bonite, and resembling the tunny, in which there is an oil which shines with a considerable lustre; and, although he has observed, and accurately described, several of the luminous insects that are found in sea-water, he is, nevertheless, of opinion, that the scintillation and flaming light of the sea proceed from the oily and greasy substances with which it is impregnated.

Abbé Nollet was long of opinion, that the light of the sea proceeded from electricity; but he afterward seemed inclined to think, that this pheno menon was caused by small animals, either by their luminous aspect, or, at least, by some liquor, or ef fluvia, which, they emitted; he did not, however, exclude other causes: among these, the spawn or fry of fish deserves to be noticed. M. Dagelet, sailing into the bay of Antongil, in the island of Madagascar, observed a prodigious quantity of fry, which covered the surface of the sea above a mile in length, and which he, at first, on account of their colour, took for banks of sand. They exhaled a disagreeable odour, and the sea had appeared with uncommon splendour some days before. The same accurate observer, perceiving the sea remarkably luminous in the road of the Cape of Good Hope, during a perfect calm, remarked, that the oars of the canoes produced a whitish and pearly kind of lustre: when he took in his hand the water which contained phosphorus, he discerned in it, for some minutes, globules of light as large as the heads of pins. When he pressed these globules, they appeared to his touch like a soft and thin pulp; and some days after the sea was covered, near the coasts, with whole banks of these little fish, in innumerable multitudes. In a word, it is probable, as observed be

fore, that various causes contribute to the light and scintillation of the sea; and that the light which M. Bayon attributed to agitation and friction, is dif ferent from that which is extended far and near, which seems to cover the whole surface of the ocean, and produces a very striking and beautiful appear ance, particularly in the torrid zone, and in the

summer season.

The revolutions produced upon the earth by the sea, form another object of contemplation. It is every day making considerable alterations, either by overflowing its shores in one place, or deserting them in others; by covering over whole tracts of country, that were cultivated and peopled at one time; or by leaving its bed to be appropriated to the purposes of vegetation, and to supply a new theatre for human industry, at another.

In this struggle for dominion between the earth and the sea, the greatest number of our shores seem to defy the whole rage of the waves, both by their height, and the rocky materials of which they are composed, which defend the land, and are only interrupted here and there, to give an egress to rivers, and to afford to our shipping the conveniencies of bays and harbours. In general, it may be remarked, that wherever the sea is most furious, there the boldest shores, and of the most compact materials, are found to oppose it. There are many shores se veral hundred feet perpendicular, against which, the sea, when swollen with tides or storms, rises and beats with inconceivable fury.

Hence, therefore, we may conceive, how the violence of the sea, and the boldness of the shore, may be said to have made each other. When the sea meets no obstacles, it swells its waters with a gentle intumescence, till all its power is destroyed, by wanting depth to aid its motion. But when its progress is checked in the midst, by the prominence