which was exceedingly well tasted. Our cookery at Rykum had not been quite so successful. The water thrown out from the Geyzer is joined at the bottom of the mound by that which flows from the spring called the roaring Geyzer, formerly described. The stream produced by their united waters flows three or four hundred paces before it falls into the river, where its temperature is reduced to 72°. Even at this place it deposited much of the substances it contained; but during the whole of its course, the plants growing on its banks were covered with beautiful incrustations. Some of these we wished to preserve, but from their extreme delicacy they fell into pieces on every attempt to remove them. he situation of the new Geyzer is in the same line from the foot of the hill with the great Geyzer. Its pipe is formed with equal regularity, and is six feet in diameter, and forty-six feet ten inches in depth. It does not open into a bason, but it is nearly surrounded by a rim or wall two feet high, After each eruption, the pipe is emptied, and the water returns gradually into it as into that of the old Geyzer. During three hours nearly that the pipe is filling, the partial eruptions happen seldom, and do not rise very high; but the water boils the whole time, and often with great violence. The temperature of the waters after one of these eruptions, was constautly found to be 22°. Few incrustations are formed round this spring, excepting in the channel where the water flows from it. The great eruption is not preceded by any noise, like that of the great Geyzer. The water boils suddenly, or is heaved over the Before the month of June 1789, the year I visited Iceland, this spring had not played with any degree of violence, at least for a considerable time. (Indeed the formation of the pipe will not allow us to suppose, that its eruptions had at no former period been violent.) But in the month of June, this quarter of Iceland had suffered some very severe shocks of an earthquake; and it is not unlikely, that many of the cavities communicating with the bottom of the pipe had been then enlarged, and new sources of water opened into them. The difference between the eruptions of this fountain, and those of the great Geyzer, may be accounted for from the circumstance of there being no bason over the pipe of the first, in which any water can be contained to interrupt the coJumn as it rises. I should here state, that we could not discover any corres pondence between the eruptions of the different springs. sides of the pipe; then subsiding a little, it bursts into the air with inconceivable violence. The column of water remains entire, untiH it reaches its extreme height, where it is shivered into the finest particles. Its direction was perpendicular, and greatest elevation 132 feet. Like the eruption of the old Geyzer, this consisted of several jets, succeeding each other with great rapidity. Whatever we threw into the well was hurled into the air with such swiftness that the eye could scarcely discern it*, and the division of the water at the extremity of the column was so minute, that the showers of spray which fell were cold. Towards the end of an eruption, when more steam than water rushed from the pipe, I ventured to hold my hand near the edge of the column, in the way of some divided particles of water, and found them tepid only. You may probably think this a rash experiment, and certainly it was so. But we had made our observations on the uniform direction of the column, aud confided our safety in it. Once or twice, however, we had reason to think ourselves more fortunate in escaping, than prudent iu avoiding, the danger which attended a too near approach to these eruptions of boiling water. During ten or fifteen minutes, the water continued to be thrown upwards with undiminished impetuosity. At the end of that period, the quantity became less, and at length, ceasing entirely, steam alone ascended. In one instance, the eruption coutinued thirty minutes. It seldom however exceeded twenty minutes, and sometimes was completed in fifteen minutes. The force with which the steam rises abates as the water sinks in the pipe, and when this is exhausted, that soon disappears. I have now given you such a description of these celebrated fountains as was in my power. I hope that it will afford you some satisfaction, and I could wish that it might serve as an inducement to some curious inquirer into the history of nature to visit them, who shall have all the knowledge requisite for making such observations as are yet to be desired concerning them. I cannot flatter myself, that the description I have attempted of their eruptions will impress you with a just idea of their beauty. Sources of comparison are wanting, by which the portraiture of such extraordinary * Mr. Baine measured the height to which a stone was thrown up by one of these jets, and found it 129 feet. Some others rose considerably higher. scenes can be assisted. Nature no where offers objects bearing a resemblance to them; and art, even in constructing the water-works of Versailles, has produced nothing that can at all illustrate the magnificent appearances of the Geyzer. All then that I hope for is, to have said so much as may enable you to complete in your imagination, the picture which I bave only sketched. Imagination alone can supply the noise and motion which accompany such large bodies of water bursting from their confinement; and must be left to paint what I have not been able to describe, the brilliancy of colouring, the purity of the spray, the quick change of effect, and the thousand varieties of form into which the clouds of steam, filling the atmosphere on every side, are rolled incessantly. I have avoided entering into any theory of the cause of these phenomena, that you may not suppose the account I give you has been biassed by a favourite hypothesis: I have given you an accurate state of facts, and I leave to you the explanation of them. There cannot, however, be two opinions concerning the immediate cause which forces the water upwards. It is obviously the elasticity of steam endeavouring to free itself. In addition to this, the form of the cylinder through which the water rises, gives it that projectile force which carries it so high. Beyond this, it would not become me to hazard any opinion. Of the antiquity of these springs I can say nothing further than that they are mentioned as throwing up their waters to a great height by Saxo Grammaticus, in the Preface to his History of Denmark, which was written in the twelfth century; but from the general fea ́tures of the country, it is likely that they have existed a great length of time. The operations of subterraneous heat seem indeed to be of great antiquity in Iceland; and the whole country probably owes its existence to the fires which burn beneath its surface. Every hill proves, at least, with what violence these fires have acted for ages; and the terrible eruption of lava which burst from the mountains of Skaptefield in 1783, show that they are as yet far from being axtinguished. [Transactions of the Royal Society of Edinburgh, Vol. 3.] SECTION VI. Alternating Hot and Cold Springs. THERE are many tepid springs which, without any real change in their temperature, appear to the people that frequent them to be much warmer in the winter than in the summer. Of these we have already given an example in the preceding section, in describing the warm springs in the district of Troas. The apparent variation in such cases depends altogether upon the real variation in the temperature of the atmosphere: the water sinking the thermometer be low the temperature of the surrounding air in summer, but raising it perhaps twenty or thirty degrees above that of the winter season. There are other springs and fountains, however, in which there is a real difference in the temperature of the water at different seasons, as measured by the thermometer when plunged into the water itself: and while in some instances these alterations are irregular, in others they are fixed and periodical. Both these facts have been known to natural philosophers through a long series of ages; and the last is thus minutely exemplified by Lucretius in his Nature of Things, vi. 848. Esse apud Hammonis * fanum funs luce diurnâ A fount, 'tis rumour'd, near the temple purls We quote from Wakefield's edition. GOOD. And the philosophic poet having, thus, peremptorily spurned the common theory, immediately proceeds to unfold his own, which offers a striking consonance to several of the chemical opinions of the present day. He supposes that the elementary principles of caloric are driven together and concentrated by the contraction of the sides of the fountain that takes place upon the return of the evening cold, in the same manner as we now suppose them to be driven together and concentrated by the contraction that takes place in the percussion of solid bodies; in consequence of which the water, or whatever other substance may hereby be exposed to such concentrated action, must necessarily become proportionably heated. His words are as follows, which we shall interpret in the language of the translator and annotator from whom we have already quoted. Quæ ratio est igitur? nimirum, terra magis quod Dost thou the cause demand, then ?-clearly hence: |