Among the principal rivers of Italy is the Tiber, which issues from the Apennine Mountains at a short distance from Rome, and empties itself into the Tuscan Sea. The water of this river is so muddy that horses will not drink it; and even the poets, describing the river, call it the golden Tiber, in allusion to the yellow clay with which its waters are saturated. After standing a few hours, however, the water of the Tiber becomes clear and fit to drink. "The bed of this river having been raised by the ruins of the many edifices which have fallen into it, and its mouth partially choked up, it frequently overflows its banks, more particularly during the prevalence of a strong south wind."
CHAPTER IV. SPRINGS.
As springs are the sources of rivers, it would have been scarcely necessary to speak of them under a separate head had there not been some cases in which springs are celebrated quite independently of the river which springs from them; others in which the springs, though of considerable importance in themselves, do not give birth to any river; and others in which the springs are celebrated for some quality which they possess, such as mineral springs, or springs of warm water.
SPRINGS REMARKABLE FOR THEIR SIZE.
One of the most magnificent springs in Europe is that of Petrarch's fountain at Vaucluse near Avignon. "It rises within a cavern, at the foot of a vast semi-circular precipice of compact limestone terminating a wild valley. In the beginning of autumn, by clambering over a heap of rubbish, the traveller may descend into the cavern, and will find himself on the brink of a gulf of the clearest water, of unfathomable depth, with the deep blue tint of the ocean out of soundings, rising with great force, and an unruffled surface, from the recesses of the mountain. It issues from the cavern through concealed channels, and forms at once the river Sorgue, capable at its very source of moving machinery, and almost immediately navigable for boats. The waters of this extraordinary spring never vary half a degree in temperature. When the melting of snow on the neighbouring Alps increases its sources, the cavern is entirely filled with water, and the stream rushes over the rugged bank at the mouth of the cavern with the tumult of a cascade."
The largest spring in Great Britain is St. Winifred's Well in Flintshire. This spring, which has almost the force of a subterranean river, produces about twenty-one tons of water a minute; and the water which passes through the town of Holywell, runs with such force, as to turn several mills. A chapel has been built over the spring, on the windows of which are painted the chief events in the life of the saint. A peculiar kind of lichen grows in the walls of the well, which, in the days of superstition, was believed to be St. Winifred's hair; and as some of the same lichen, which looks red when wet, was found on the stones at the bottom of the well, it was said to be the saint's blood.
INTERMITTENT SPRINGS.
One of the most remarkable of these is at Bolderborn in Westphalia. After flowing for twenty-four hours, it entirely ceases for the space of six hours. It then returns with a loud noise, in a stream sufficiently powerful to turn three mills very near its source. Another spring of the same nature occurs at Bihar in Hungary, which issues many times a day, from the foot of a mountain, in such a quantity as in a few minutes to fill the channel of a considerable stream.
The Lay Well near Torbay, ebbs and flows sixteen times in an hour; and in Giggleswick Well in Yorkshire, the water sometimes rises and falls in ten or fifteen minutes.
St. Anthony's Well, on Arthur's Seat, near Edinburgh, has a similar movement, but on a smaller scale.
In Savoy, near the lake of Bourget, is another spring of this kind, but it differs from those which have been already mentioned in being very uncertain in its intervals.
MINERAL SPRINGS.
All spring water contains a certain proportion of air, and of mineral substances; but when these latter exceed a certain proportion, the spring is said to be a mineral one. Mineral waters are of four kinds: acidulous, chalybeate, sulphureous, and saline. The first generally abound in carbonic acid, and have a sparkling appearance and an agreeable taste. Of this kind are the Seltzer and Spa waters in Germany, and the Tonbridge waters in England; the latter, however, being less agreeable than the former, as they are impregnated with iron. The chalybeate springs all contain either the carbonate or sulphate of iron; and in some of them one or two grains are found of oxide of iron combined with other salts. There are various chalybeate springs in England; and in some places there are chalybeate springs in addition to those which have given their principal celebrity to the place, as for example, there are chalybeate springs at Buxton, Harrogate, and Cheltenham, in addition to others of quite a different nature. Chalybeate springs are considered strengthening, but they are injurious when taken by persons of an inflammatory habit. The sulphureous waters owe their qualities to sulphuretted hydrogen, and are extremely disagreeable both in taste and smell. The principal ones in England are those at Harrogate and Leamington. The waters at Kilburn, near London, on the Edgware road, which were formerly celebrated, were of this kind. At Wigan, in Lancashire, there is a sulphureous spring, the waters of which burn like oil. On applying a lighted candle to the surface a large flame is produced which burns vigorously, though the water itself is quite cold; and the earth which has been wet by the water, and has become dry, will burn also in the same manner.
At Broseley in Shropshire, in the month of June, 1711, a boiling spring was discovered under a small hill about 200 yards from the river Severn. It was announced by a tremendous noise in the middle of the night, and which was described by those who heard it, as sounding as if there were a thunder storm under ground. Some persons who lived in the neighbourhood had the curiosity to go to the spot from which the noise proceeded, when they found an extraordinary commotion and shaking of the earth, with a little bubbling up of water through the grass. One of the party had the courage to take a spade, and to force it into the ground, when the water immediately flew up to a great height, and was set on fire by a candle which was held by one of the work-people. It was found, however, on further examination, that the water was perfectly cold, and that though it burnt fiercely when set on fire it soon went out.
The saline springs are very numerous, but the most celebrated are those at Cheltenham, Leamington, and Epsom. Seidlitz springs are of this nature. They are all rather unpleasant in taste, but have very little smell.
The dropping well or petrifying spring at Knaresborough rises at the foot of a limestone rock near the bank of the river Nidd. "The spring, after running about sixty feet, divides, and spreads itself over the top of the rock, whence it trickles down, from thirty or forty places, into a channel hollowed for the purpose, each drop producing a musical kind of tinkling, probably owing to the concavity of the rock, which, bending in a circular projection, from the bottom to the top, occasions its brow to overhang about fifteen feet." The water contains nitrous earth, which it deposits upon any object placed within reach of its waters, dropping very slowly, so as to incrust the leaves, moss, &c., which it meets with; and as objects thus incrusted resemble stone, they are said to be petrified. The persons who show the well have several curious objects thus incrusted, which they exhibit, and amongst other things an old wig and a bird's nest, which look as if they were really turned into stone.
HOT SPRINGS.
The most celebrated hot springs of England are those at Bath, which are acidulous, and the heat of which is 116° where they issue from the earth. The hot springs at Bristol, Buxton, and Matlock, are of the same nature, but of a much lower temperature, those at Buxton, which are the warmest of the three, not exceeding 82°, and those at Matlock being only 66°. One of the warmest springs used for a bath is that at Carlsbad, where the waters are 167°. The waters are also very warm at Aix-la-Chapelle, and as they are sulphureous, their smell is intolerable. The most extraordinary hot springs in the world, however, are the Geysers of Iceland, and another boiling spring in the same island, which issues from a small mass of rock, in the midst of a large river. The Geysers are celebrated for their intermissions, and for the magnificent jets of boiling water which they throw out. Two of the largest of these fountains are in a valley about sixteen miles from Skalholt. In the middle of this valley is a little mount, six or seven feet high, in the centre of which is a circular basin, from fifty to sixty feet in diameter, and about three feet deep. In the centre of this basin is a round hole about ten feet wide, which is the mouth of a natural pipe or funnel which sinks into the earth to the depth of nearly eighty feet. By this pipe, the water occasionally retires, leaving the basin quite dry; but at regular intervals, which differ in the different fountains, the water begins to bubble up till it has gradually filled the basin, even to overflowing, and as soon as it has done so, the ground is shaken by hollow subterraneous convulsions, and "suddenly a prodigious column of boiling water is shot into the air with astonishing violence, and clouds of steam obscure the atmosphere. This is followed by successive jets, sometimes to the number of sixteen or eighteen in five minutes." The heights to which the jets rise are from ninety to 212 feet, the latter being the height of one measured by Lieutenant Ohlsen in 1804. These hot water springs appear evidently of volcanic origin, and whenever an earthquake shakes the island it is sure to be attended by the formation of fresh boiling springs. The waters of the great Geyser hold an immense quantity of flinty matter in solution, and where they overflow the basin, they deposit a stony crust upon the adjacent plants. The jets "are attended with a loud noise, and the ground trembles beneath the feet, whilst the velocity with which the jets and the accompanying steam are hurled into the air is astonishingly sublime. When stones are thrown into the pipe, they remain there until the succeeding jet projects them with great violence into the air, and they may be seen descending amid showers of boiling water."
Besides these very remarkable fountains, hot water springs have been discovered in various parts of the world, and amongst other places at St. Michael's in one of the Azores, where the water is of such an intense heat that it will boil an egg.
The boiling spring at Solfatara near Naples is another example, and many others might be mentioned; but in most cases the wonder is somewhat diminished by the circumstance of the spring being evidently connected with a volcano, and thus the hot springs in England may be said to be the most wonderful in the world as there is no volcano near them.
In New Zealand, near the volcano of Tongariro, boiling springs burst out of the ground, which are thus described by Mr. Angas. "The crater of Tongariro is an immense truncated cone, giving vent, like an enormous safety-valve, to the steam and vapours that proceed from the boiling waters in its subterranean depths. Several other mountains are grouped with the stupendous peak of Tongariro, forming one grand mass or cluster; and the snow extends for a considerable distance down their sides. Near the termination of the snow there are boiling springs, which send up volumes of steam. Forests clothe the lower sides for some miles, and fern hills commence the ascent. It is only at intervals that any considerable quantity of steam issues from the crater. When I first saw the mountain from across the lake, there was no appearance of vapour, but after sunset it rose in continuous masses. The lake Rotoaira is upwards of 2,000 feet above the level of the sea, and there are numerous snow-fields and glaciers in the immediate neighbourhood." Nearly 100 boiling springs issue from the side of a steep mountain above Te Rapa. "They burst out, bubbling up from little orifices in the ground, which are not more than a few inches in diameter, and the steam rushes out in clouds with considerable force: the hill-side is covered with them, and a river of hot water runs down into the lake. The soil around is a red and white clay, strongly impregnated with sulphur and hydrogen gas: pyrites also occur. Several women were busy cooking baskets of potatoes over some of the smaller orifices; leaves and fern were laid over the holes, upon which the food was placed: I tasted some of the potatoes and they were capitally done." "About two miles from this place," Mr. Angas continues, "on the edge of a great swampy flat, I met with a number of boiling ponds; some of them of very large dimensions. We forded a river flowing swiftly towards the lake, which is fed by the snows melting in the valleys of the Tongariro. In many places in the bed of this river, the water boils up from the subterranean springs beneath, suddenly changing the temperature of the stream, to the imminent risk of the individual who may be crossing. Along whole tracts of ground I heard the water boiling violently beneath the crust over which I was treading. It is very dangerous travelling, for if the crust should break, scalding to death must ensue. I am told that the Rotorua natives, who build their houses over the hot springs in that district, for the sake of constant warmth at night, frequently meet with fatal accidents of this kind; it has happened that when a party have been dancing on the floor, the crust has given way, and the convivial assembly have been suddenly swallowed up in the boiling cauldron beneath. Some of the ponds are ninety feet in circumference, filled with transparent pale blue boiling water, sending up columns of steam. Channels of boiling water run along the ground in every direction, and the surface of this calcareous flat around the margin of the boiling ponds is covered with beautiful incrustations of lime and alum, in some parts forming flat saucer-like figures. Husks of maize, moss, and branches of vegetable substances were incrusted in the same manner. I also observed small deep holes, or wells, here and there amongst the grass and rushes, from two inches to as many feet in diameter, filled with boiling mud, that rises up in large bubbles, as thick as hasty pudding: these mud pits send up a strong sulphureous smell. Although the ponds boiled violently, I noticed small flies walking swiftly, or rather running on their surface. The steam that rises from these boiling springs is visible at a distance of many miles, appearing like the jets from a number of steam engines."