Letters From High Latitudes [35]
of a pipe, whose lower orifice, instead of being in the roof, is at the side of the cavern, and BELOW the surface of the subterranean pond. The water kept by the surrounding furnaces at boiling point, generates of course a continuous supply of steam, for which some vent must be obtained; as it cannot escape by the funnel, the lower mouth of which is under water, it squeezes itself up within the arching roof, until at last, compressed beyond all endurance, it strains against the rock, and pushing down the intervening waters with its broad, strong back, forces them below the level of the funnel, and dispersing part, and driving part before it, rushes forth in triumph to the upper air. The fountains, therefore, that we see mounting to the sky during an eruption, are nothing but the superincumbent mass of waters in the pipe driven up in confusion before the steam at the moment it obtains its liberation. [Footnote: Professor Bunsen has lately announced a chemical theory, which I believe has been received with favour by the scientific world. He points to the fact that water, after being long subjected to heat, loses much of the air contained in it, has the cohesion of its molecules much increased, and requires a higher temperature to bring it to boil; at which moment the production of vapour becomes so great, and so instantaneous, as to cause explosion. The bursting of furnace boilers is often attributable to this cause. Now, the water at the bottom of the well of the Great Geysir is found to be of constantly increasing temperature up to the moment of an eruption, when on one occasion it was as high as 261 degrees. Fahrenheit. Professor Bunsen's idea is, that on reaching some unknown point above that temperature, ebullition takes place, vapour is suddenly generated in enormous quantity, and an eruption of the superior column of water is the consequence.]
The accompanying sketch may perhaps help you to understand my meaning.
[Figure: fig-p074.gif]
The last gulp of water had disappeared down the funnel. We were standing at the bottom of the now empty basin, gazing into each other's faces with joyous astonishment, when suddenly we perceived a horseman come frantically galloping round the base of the neighbouring hill towards us. The state of the case was only too evident. He had seen the masses of vapour rising round the fountain, and guessing "what was UP", had strained every nerve to arrive in time. As there was no mutual friend present to introduce us to each other,--of course under ordinary circumstances I should have wrapped myself in that reserve which is the birthright of every Briton, and pretended never even to have noticed his arrival; but the sight we had just seen had quite upset my nerves,--and I confess, with shame, that I so far compromised myself, as to inaugurate a conversation with the stranger. In extenuation of my conduct, I must be allowed to add, that the newcomer was not a fellow-countryman, but of the French tongue, and of the naval profession.
Occupying then the door of my tent--by way of vantage ground, as soon as the stranger was come within earshot, I lifted up my voice, and cried in a style of Arabian familiarity, "O thou that ridest so furiously,--weary and disappointed one,--turn in, I pray thee, into the tent of thy servant, and eat bread, and drink wine, that thy soul may becomforted." To which he answered and said, "Man,--dweller in sulphureous places,--I will not eat bread, nor drink wine, neither will I enter into thy tent, until I have measured out a resting-place for my Lord the Prince."
At this interesting moment our acquaintance was interrupted by the appearance of two other horsemen--the one a painter, the other a geologist--attached to the expedition of Prince Napoleon. They informed us that His Imperial Highness had reached Reykjavik two days after we had left, that he had encamped last night at Thingvalla, and might be expected here in about four hours: they themselves having come on in advance to prepare for his arrival. My first care was to order coffee for the tired
The accompanying sketch may perhaps help you to understand my meaning.
[Figure: fig-p074.gif]
The last gulp of water had disappeared down the funnel. We were standing at the bottom of the now empty basin, gazing into each other's faces with joyous astonishment, when suddenly we perceived a horseman come frantically galloping round the base of the neighbouring hill towards us. The state of the case was only too evident. He had seen the masses of vapour rising round the fountain, and guessing "what was UP", had strained every nerve to arrive in time. As there was no mutual friend present to introduce us to each other,--of course under ordinary circumstances I should have wrapped myself in that reserve which is the birthright of every Briton, and pretended never even to have noticed his arrival; but the sight we had just seen had quite upset my nerves,--and I confess, with shame, that I so far compromised myself, as to inaugurate a conversation with the stranger. In extenuation of my conduct, I must be allowed to add, that the newcomer was not a fellow-countryman, but of the French tongue, and of the naval profession.
Occupying then the door of my tent--by way of vantage ground, as soon as the stranger was come within earshot, I lifted up my voice, and cried in a style of Arabian familiarity, "O thou that ridest so furiously,--weary and disappointed one,--turn in, I pray thee, into the tent of thy servant, and eat bread, and drink wine, that thy soul may becomforted." To which he answered and said, "Man,--dweller in sulphureous places,--I will not eat bread, nor drink wine, neither will I enter into thy tent, until I have measured out a resting-place for my Lord the Prince."
At this interesting moment our acquaintance was interrupted by the appearance of two other horsemen--the one a painter, the other a geologist--attached to the expedition of Prince Napoleon. They informed us that His Imperial Highness had reached Reykjavik two days after we had left, that he had encamped last night at Thingvalla, and might be expected here in about four hours: they themselves having come on in advance to prepare for his arrival. My first care was to order coffee for the tired