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phenomenon often surpasses, and that of its ultimate cause always surpasses the apprehension of the human intellect.'

The saltness of those great collections of waters, that have no effluent rivers, nor visible communication with the sea, has been mentioned in the preceding quotation. But there are other lakes, through which rivers run into the sea; and these, how extensive soever, are, notwithstanding, very fresh: for admitting the first opinion, concerning the influx of rivers into the sea, and consequently of their salts; yet these rivers do not deposit their salts in the bed of the lake, but carry them, with the currents, into the ocean. Thus the lakes Ontario and Erie, in North America, although for magnitude they may be considered as inland seas, are, nevertheless, fresh water lakes, and kept so by the river St. Lawrence, which passes through them.-I shall only mention further, on this head, the opinions of Bernier and Marsigli: the former ascribes the saltness of the ocean to the fossil or mineral salts, brought into it by subterraneous currents, and dissolved in the water: the latter observes, that, in Provence, the bottom of the sea is wholly stony, and is nothing but a continuation of the mountains of the Cevennes; being even found to consist of several strata, among which are salt and pit-coal; and hence he derives the salt and bitterness of the sea-water.

The saltness of the sea has been considered by some as a peculiar blessing from Providence, in order to keep so great an element pure and wholesome. This appears to be the sentiment of Sir Richard Blackmore, in the beautiful lines with which I shall conclude this paper; observing, however, that the saltness of the sea can by no means be considered as a principal cause in preserving its waters from putrefaction; which, in my next essay, I shall endeavour to demonstrate.

What does the sea from putrefaction keep?
Should it lie stagnant in its ample seat,

The sun would through it spread destructive heat.
The wise Contriver, on his end intent,
Careful this fatal error to prevent,

And keep the waters from corruption free,
Mixt them with salt, and seasoned all the sea.
What other cause could this effect produce?
The brackish tincture through the main diffuse?
You, who to solar beams this task assign,
To scald the waves, and turn the tide to brine,
Reflect, that all the fluid stores, which sleep
In the remotest caverns of the deep,
Have of the briny force a greater share,
Than those above that meet the ambient air.
Others, but oh how much in vain, erect
Mountains of salt, the ocean to infect.

Who, versed in nature, can describe the land,
Or fix the place on which those mountains stand?
Why have those rocks so long unwasted stood,
Since, lavish of their stock, they through the flood,
Have, ages past, their melting crystals spread?
And with their spoils the liquid regions fed ?

No. LIX.

FURTHER REFLECTIONS ON THE OCEAN.

And thou, majestic main!

A secret world of wonders in thyself!

Sound His stupendous praise, whose greater voice
Or bids you roar, or bids your roarings fall.

THOMSON.

IN my preceding paper I observed, that the saltness of the sea can by no means be considered as a principal cause in preserving its waters from putrefaction. The ocean has its currents, like rivers,

which circulate its contents round the globe; and these may be said to be the great agents that keep it sweet and wholesome. Sir Robert Hawkins, one of our most enlightened navigators, gives an 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 Azores, almost six months; the greatest part of which time we were becalmed. Upon which all the sea became so replenished with various sorts of gellies, and forms of serpents, 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 two yards long; which had I not seen, I could hardly have believed. And hereof are witnesses all the companies of the ships which were then present; so that hardly a man could draw a bucket of water clear of some corruption. In which voyage, toward the end thereof, many of every ship fell sick, and began to die apace. But the speedy passage into our country, was a remedy to the crazed, and a preservative for those that were not touched.'

This shows, sufficiently, how little the saltness of the sea is capable of preserving it from putrefaction. Mr. Boyle, moreover, once kept a quantity of sea water, taken from the English channel, for some time, barrelled up; and, in a few weeks, it began to acquire a fetid smell. He was also assured by one of his acquaintance, who had been becalmed, for about fourteen days, in the Indian ocean, that the water, for want of motion, began to stink; and, that had the calm continued much longer, the stench would probably have poisoned him. It is the mo

tion, therefore, and not the saltness of the sea, that preserves it in its present state of salubrity; and this, very probably, as I have lately observed, by dashing and breaking in pieces the rudiments, if I may so call them, of the various animals, that would otherwise breed and putrefy in the sea.

The saltness of the sea, however, is not unproductive of some advantages. 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 is a stronger kind, made in warm climates, such as Italy, Spain, and the southern provinces of France, by evaporation in the sun that called common salt is made by evaporation in pans over the fire, and is of a much inferior quality to the former.

Another benefit arising from the quantity of salt dissolved in the sea, is, that it thus becomes heavier, and, consequently, more buoyant. Mr. Boyle, who examined the difference between sea water and fresh, found that the former appeared to be about a fortyfifth part heavier than the latter. Those persons also, who have had opportunities of bathing in the sea, pretend to have experienced a much greater degree of ease in swimming there, than in fresh water. However, as we see that they have only a forty-fifth more of their weight sustained by it, I am inclined to doubt, whether so minute a difference can be practically perceptible. Be this as it may, as sea water alters in its weight from fresh, so also it is found to differ from itself in different parts of the In general, it is perceived to be heavier, and consequently, salter, the nearer we approach the line'.

ocean.

It appears from some experiments formerly made in a

There is one question, concerning the saltness of the sea, which does not yet appear to be decided; namely, whether it be heavier at the surface, or at the bottom. Mr. Boyle found, that equal bulks of water taken up in the English channel at the surface, and at the depth of fifteen fathoms, were equally heavy, and hence he concludes, that the superficial water was as salt as that at a great depth.

On the other hand, Count Marsigli obtained by evaporating the water a thirty-second part only of its weight of salt from water, taken up on the surface of the sea in the gulf of Lyons, while that taken up at the same time and place, from a great depth, gave him a twenty-ninth part of its weight of salt; and he thence infers, the greater saltness of the sea at the bottom than at its surface. In this conclusion he has been supported by experiments made in the gulf of Bothnia.

There can be no reason to suspect the accuracy with which any of these experiments was made: in different places the facts will probably be different. The river Rhone discharges much fresh water into the gulf of Lyons: this fresh water being lighter than the sea water, will not readily mix itself with it, and for this reason the superficial water will be most diluted by it, and from that circumstance will contain less salt, in a definite quantity, than the water which is at a greater depth. At Northwich the manufacturers of salt pump their brine, which is to be boiled into salt, into a very large circular basin, sunk in the ground, and lined with brick, from which, when its impurities are subsided, it is conveyed to the boiling pans. This basin is exposed to

voyage from Bombay to the East Indies, that the weight of the sea water was the greatest, not precisely at the equator, but where the sun was vertical, and, consequently, in similar circumstances, where the heat was greatest. Watson's Chem. Essays, vol. ii. page 114.

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