against the sides of mountains (many of which far exceed the usual height to which vapours would of themselves ascend), are compelled by the stream of air to mount up with it to their summits. There, being condensed into water, they presently precipitate, and, oozing down by the crannies of the stones, part of them enters into the caverns of the hills. These being once filled, all the overplus of water that comes thither runs over by the lowest place, and, breaking out by the sides of the hills, forms single springs. Many of these running down by the vallies, between the ridges of the hills, and coming to unite, form little rivulets or brooks. Many of these again meeting in one common valley, and, by gaining the plain ground, having grown less rapid, become a river: and many of these uniting, form such prodigious streams of water as the Volga, the Danube, and the Rhone.

Thus, one part of the vapours that are blown on the land is returned by the rivers to the sea whence it came. Another part falls into the sea before it can reach the land; which is the reason why the rivers do not return so much water into the Mediterranean as is raised by vapour. A third part falls upon the low grounds, and furnishes the pabulum or nutriment of plants. But the circulation does not end even here; for it is again exhaled into vapour by the action of the sun, and returned to the great world of waters whence it first arose.

Thomson, in his poetical account of the origin of fountains, seems to have blended the theories of Mariotte and Halley:

Where lurk the dark eternal springs,
That, like creating Nature, lie concealed
From mortal eye, yet with their lavish stores
Refresh the globe, and all its joyous tribes?

O thou pervading Genius, given to man,

To trace the secrets of the dark abyss,

O, lay the mountains bare! and wide display
Their hidden structure to th' astonished view!

Amazing scene! Behold! the glooms disclose;
1 see the rivers in their infant-beds!

Deep, deep I hear them, lab'ring to get free?
I see the leaning strata, artful ranged;
The gaping fissures to receive the rains,
The melting snows, and ever-dripping fogs.
Strowed bibulous above I see the sands,
The pebbly gravel next, the layers then
Of mingled moulds, of more retentive earths,
The guttered rocks, and mazy-running clefts;
That, while the stealing moisture they transmit,
Retard its motion, and forbid its waste.
Beneath th' incessant weeping of these drains,
I see the rocky syphons stretched immense,
The mighty reservoirs of hardened chalk,
Or stiff-compacted clay, capacious formed.
O'erflowing thence, the congregated stores,
The crystal treasures of the liquid world,
Through the stirred sands a bubbling passage burst;
And welling out, around the middle steep,
Or from the bottoms of the bosomed hills,
In pure effusion flow. United, thus,
Th' exhaling sun, the vapour-burdened air,
The gelid mountains, that to rain condensed
These vapours in continual current draw,
And send them, o'er the fair-divided earth,
In bounteous rivers to the deep again,
A social commerce hold, and firm support
The full-adjusted harmony of things.

But although the theory of Dr. Halley appears thus beautiful, and seems indeed to be most genetally adopted, it must still be confessed to be encumbered with great difficulties. The perpetuity of many springs, which always yield the same quantity when the least rain or vapour is afforded, as well as when the greatest, is a strong objection to both. Dr. Derham mentions a spring at Up

minster, in Essex, which he could never perceive by his eye to be diminished, in the greatest droughts, even when all the ponds in the country, as well as an adjoining brook, had been dry for several months together; nor ever to be increased in the most rainy seasons, excepting, perhaps, for a few hours, or, at most, for a day, from sudden and violent rains. He, therefore, justly concludes, that had this spring its origin from rain or vapour, there would be found an increase or decrease of its water, corresponding to the causes of its production. Another important thing must not be forgotten of this Upminster spring, and of thousands of others; namely, that it breaks out of so inconsiderable an eminence, as can have no more influence on the condensation of the vapours, or stopping the clouds, than the lower lands about it.-Ricciolus, and other naturalists, deny that rain or dew can be a sufficient supply for the great perennial springs, and much less for the constant current of the larger rivers. The Volga alone, they say, pours forth as much water in a year's time into the Caspian sea, as would suffice to drown the surface of the whole earth. They affirm, moreover, that this river, and the other rivers on the several parts of the globe, upon a very moderate calculation, discharge at least as much water into the sea, as falls upon the surface of the whole earth in rains, mists, dews, snows, &c. in a like space of time.-Nor, upon Dr. Halley's theory, can they account for the origin of hot and salt springs, nor of those springs which rise in places where there falls little or no rain.-Hence they have recourse, and particularly Dr. Plot, in his 'Tentamen de Origine Fontium,' to certain subterranean communications between the sea and the sources of fountains, rivers, and the larger springs, by which these are supplied; and they

assert that there are certain charybdes, or apertures, which swallow the sea for this purpose

Whither then shall we wander in search of certainty, when the most learned disagree; when long and laborious calculations are adduced by all sides, that seem only to involve the subject in obscurity? But, whatever be the uncertainty of philosophers on this subject, the unspeakable advantages which we derive from fountains and rivers are obvious to the most uninformed. Omniscience alone can comprehend all the operations of Omnipotence. Nor is it only in the great work of our Redemption, but in the astonishing mysteries of Nature, that we may exclaim with the Apostle Paul: O the depth of the riches both of the wisdom and knowledge of God! How unsearchable are his judgments, and his ways past finding out!....Of him, and through him, and to him, are all things: to whom be glory for ever, Amen.'

I might enlarge this discussion with a variety of interesting particulars relative to fountains and rivers. But I shall wave these, for the present, in order to lay before my readers a poetical description, never published before, of the progress of a river from its source to the sea. As it is intended to be descriptive only of scenes that may be supposed to be familiar to an English eye, it takes no notice of the thundering cataracts, golden sands, and other objects of savage climes; nor will it be considered, perhaps, as defective, in not containing a single allusion to river-gods and water-nymphs, or to any of the trite machinery of antient fiction.

The most accurate experiments on evaporation are those of Mr. Dalton. For an account of them, with their application to the present subject, the reader may consult the Manchester Memoirs; or, for a succinct view (though too extended for insertion here), the article Evgporation, in that valuable work the PANTOLOGIA.

Behold the riv'let, from its parent-source,
Steal thro' the thicket with unheeded course;
Of future greatness yet unconscious stray,
Like infant princes, in their infant play;
O'er its rough bed in lulling murmurs flow,
Or thro' the breezy sedge meand'ring slow.
And now in waves, impelling-soft, it roves
Thro' sunny banks, or deep involving groves;
From sister-streams receives enriching aid,
And wonders at the progress it has made.
Now tufty isles the doubtful stream divide,
The sacred haunts of Cygnus' plumy pride:
O'er the clear crystal hangs the woody scene,
The weeping willow, or bright ever-green.
The trembling branches, all inverted, seem
To point to other skies below the stream.
The sun reflected, gilds th' illusive deep,
Or shadowing winds the mantling surface sweep
Here thick'ning grass invites the mower's scythe,
The busy groups of men and maidens blithe;
Here the shorn meadow brightens to the eye;
The scattered herds lie ruminating nigh:
Each rising charm the bounteous stream bestows,
The grass that thickens, and the flower that blows
And while the vale the humid wealth imbibes,
The fost'ring wave sustains the finny tribes;
The carp, with golden scales, in wanton play;
The trout, in crimson-speckled glory gay;
The red-finned roach, the silver coated eel,
The pike, whose haunt the twisted roots conceal;
The healing tench, the gudgeon, pearch, and bream,
And all the sportive natives of the stream.
The vig'rous stream now drives the busy mill,
And now disdains the little name of rill.
The clust'ring cots adorn its flow'ry sides,
Where blest Content, with rosy Health, abides.
Or here the villa's simple charms invite,
Where rural ease and elegance unite.
There, gaudy Art her cumb'rous pomp displays,
Where gay Caprice bedecks the verdant maze
The palace, column, temple, statue, rears;
While Nature fashionably drest appears,
And now the bridge, by busy mortals trod,
High over-arches the ambitious flood.
Now crowded cities, lofty turrets rise,
And smoking columns mingle with the skies;