waters and to supply them afresh. And in such cases the flux and reflux of the upper head of water must necessarily depend upon the state of that below; and the causes which alternately augment and diminish the latter must produce a similar effect upon the former. And it is possible that these causes may be, as we shall presently find was long ago ingeniously conjectured by the younger Pliny, regular currents of air produced by the penetrating influence of the —a communication with the sea itself: or a periodical return of subterranean heat or other agency below the interior reservoir that may drive additional waters into it, or expand those of which it consists.

sun,

In the present day, however, the common principle upon which this phænomenon is accounted for is that of the hydraulic machine, called the Cup of Tantalus :-an instrument consisting of a vessel furnished with a siphon or tube with two legs, the one shorter than the other, and which may be attached to it in different ways. But this will not account for fountains with irregular ebbs and flows; and hence, Mr. Gough, while he attributes the regularly recurrent springs to the explanation of a siphon, has proposed another theory to account for those of a different kind, and which, in truth, is not far removed from one of the modes conjectured by the younger Pliny. Mr. Gough's theory, together with his explanation of the common theory of the siphon, we shall give in a subsequent part of the present section, allotted to an account of the alternating well at Giggleswick, in Yorkshire.

In Switzerland springs and lakes of this kind are peculiarly common; and Mr. Addison in his Travels endeavours to account for those which he met by a different process, but a process however which it must be obvious can only apply to a few. We saw, says he, in his description of Geneva and the lake, in several parts of the Alps that bordered upon us, vast pits of snow; as several mountains, that lie at greater distance, are wholly covered with it. I fancied the confusion of mountains and hollows, I here observed, furnished me with a more probable reason than any I have met with, for these periodical fountains in Switzerland which flow only at particular hours of the day. For as the tops of these mountains cast their shadows upon one another, they hinder the sun's shining on several parts at such times, so that there are several heaps of snow which have the sun lying upon them for two or three hours

G

together, and are in the shade all the day afterward. If, therefore, it happens that any particular fountain takes its rise from any of these reservoirs of snow, it will naturally begin to flow on such hours of the day as the snow begins to melt; but as soon as the sun leaves it again to freeze and harden, the fountain dries up and receives no more supplies till about the same time the next day when the heat of the sun again sets the snows a-running that fall into the same little conduits, traces and canals, and by consequence break out and discover themselves always in the same place. EDITOR.

2. Comian Spring.

PLINY TO LICINIUS.

I HAVE brought you, as a present, out of the country, a query which well deserves the consideration of your extensive knowledge. There is a spring which rises in a neigbouring mountain, and, running among the rocks, is received into a little banquettingroom, from whence, after the force of its current is a little restrained, it falls into the Larian lake *. The nature of this spring is extremely surprising: it ebbs and flows regularly three times a day.

* Now the Lago di Como, in the duchy of Milan.

Como or Comum is the city in which the younger Pliny was born; and upon the banks of the lake his elegant villa was situated.

In the Natural History of the elder Pliny, book II. chap. ciii. we are also told of a fountain in the vicinity of the same lake which ebbs and flows every hour; and Catani, and various other writers have conceived that both descriptions refer to one common fountain, and have consequently pretended to detect a palpable disagreement between the elder Pliny and his nephew; Catani supporting the testimony of the former from ocular observation, the fountain being, as he tells us, still in existence in his own time, and denominated Pliny's well. It is by no means certain, however, that the fountain described by each of these writers is the same, nor does its character, as given by the one, very strictly accord with that given by the other. The elder Pliny expressly denominates it "a large and broad well;" while the latter represents it as a small enclosed well; or in his own words, " a well received into a little banquetting-room." The point however is not of consequence. There are various other wells of a similar kind which are noticed by the elder Pliny, and especially that of Jupiter, in Dodona, of which the reader will meet with a farther account in another section of this chapter.

EDITOR.

The increase and decrease is plainly visible and very amusing to observers. You sit down by the side of the fountain, and whilst you are taking a repast, and drinking its water, which is extremely cool, you see it gradually rise and fall. If you place a ring or any thing else, at the bottom, when it is dry, the stream reaches it by degrees till it is entirely covered, and then gently retires; and if you wait you may see it thus alternately advance and recede three successive times. Shall we say that some secret current of air stops and opens the fountain-head as it approaches to or retires from it, as we see in bottles, and other vessels of that nature, when there is not a free and open passage, though you turn their necks downwards, yet the outward air obstructing the vent, they discharge. their contents as it were by starts? But may it not be accounted for upon the same principle as the flux and reflux of the sea? Or as those rivers which discharge themselves into the sea, meeting with contrary winds and the swell of the ocean are forced back into their channels: so may there not be something that checks this fountain, for a time, in its progress? Or is there rather a certain reservoir that contains these waters in the bowels of the earth, which, while it is recruiting its discharges, the stream flows more slowly and in less quantity; but when it has collected its due measure, it runs again in is usual strength and fulness. Or, lastly, is there on E know not what kind of subterraneous counterpoise that throws up the water when the fountain is dry, and stops it when it is full? You, who are so well qualified for the enquiry, will examine the reasons of this wonderful phenomenon: it will be sufficient for me, if I have given you a clear description of it. Farewell.

3. Paderborn Spring.

[Melmoth's Trans.]

IN the diocese of Paderborn, in Westphalia,there is a spring which disappears twice in twenty-four hours, returning always after six hours with a great noise, and so forcibly as to drive three mills not far from its source. The inhabitants call it the bolderborn, that is, the boisterous spring.

[Phil. Trans. 1665.]

There are various chemical remarks appended to the above brief

description, which, from the loose and unsettled state of the science in this early perod of its existence, are of no value in the present day. Whilst upon this diocese, however, we may be permitted to remark that Paderborn appears at the era before us to have been celebrated for various springs of an extraordinary nature, since in the same volume we meet with the following account, which we quote rather for its singularity than its containing any thing that can be very minutely depended upon in the present more accurate and cautious state of science.

"In the diocese of Paderborn, about two leagues from that town, is a spring,called Metborn, with three streams, two of which are not above one foot and half distant from each other, and yet of such different qualities, that one of them is limpid, bluish, lukewarm, and bubbling, containing sal-ammoniac, oker, iron, vitriol, alum, sulphur, nitre, and orpiment*, used against epilepsies, diseased spleens, and the worms; the other is ice-cold, turbid, and whitish, much stronger in taste, and heavier than the former, containing much orpiment, salt, iron, nitre, and some sal-ammoniac, alum, and vitriol. All birds that drink of the latter are observed to die; which I have also made experiment of, by taking some of it home, and giving it to poultry, after having eaten oats, barley, and bread-crumbs: for soon after drinking it, they became giddy, reeled and tumbled upon their backs, with convulsions, and so died with their legs much extended. Giving them common salt immediately after they had drunken, they lived longer; giving them vinegar, they died not at all, but seven or eight days after were troubled with the pip. Those that died being opened, their lungs were found quite shrivelled. Yet some persons who are troubled with worms, taking a little quantity of it diluted with common water, have been observed by this means to kill the worms in their bodies, and discharged great numbers of them and though it makes them sick, yet not so as to endanger their lives.

The third stream, lying lower than the other two, and about 20 paces distant from them, is of a greenish colour, very clear, and of a sourish ́sweet taste, agreeable enough. Its weight is a medium

* The chemical analysis of mineral waters was so imperfectly understood in the 17th century, that little reliance can be placed on the number and proportion of ingredients assigned in this and other instances.

between that of the other two; whence it is probable that it is a mixture of both, meeting there together: To confirm which, we mixed equal quantities of those two with a little common wellwater, and found, on stirring them together. and permitting them to settle, that they produced water of the same colour and taste as this third stream." EDITOR.

4. Lay-well Spring.

GOING a-shore one day, I walked about a mile into the country, to see a well much talked of, near Torbay, called Lay-well, which made me more than amends for the pains I had taken to come at it. It is about 6 feet long, 5 feet broad, and near 6 inches deep; and it ebbs and flows often every hour, very visibly; for from highwater to low-water mark, which I measured, I found it somewhat more than 5 inches. I could not see any augmentation above my mark when it flowed, nor fell it below my mark when it ebbed, but always kept the same distance. The flux and reflux, taken both together, was performed in about two minutes; nothing could be more regular, each succeeding the other as the tides of the sea do. I drank of it, and found it a pleasant, delicate, fine, soft-water, not brackish at all; which the country people use in fevers as their ordinary diet drink, which succeeds very well.

On a second visit, I observed it performed its flux and reflux in little more than a minute's time, yet it would stand at its lowest ebb sometimes two or three minutes; so that it ebbed and flowed by my watch about 16 times in an hour, and sometimes, I have been told, 20. As soon as the water in the well began to rise, I saw a great many bubbles ascend from the bottom; but when the water began to fall, the bubbling immediately ceased. The whole country adjacent is very hilly all along the coast; from Brixam to the top of the hill is about a mile and half, the well is about half way up the hill, which hereabout is somewhat uneven and interrupted, and comes out at a small descent, yet considerably higher than the surface of the sea. The water does not seem to be impregnated with any mineral, Its taste is very soft and pleasant, has no manner of roughness in it, and serves for all manner of uses to the country people in their houses *. [Phil. Trans. 1693.]

There is another description of this spring contained in the same excellent Journal, year 1732, by Mr. Joseph Atwell, and attempted to be explained by him