watercourse: the bottom of this is also full of little blubbering springs; and the red mound in the angle between these channels is pierced with openings from which steam rises.

On ascending the hill above the springs, which is composed of red bolus, very similar to that of Nămarfjall, I found sintery heaps covered with red clay. By means of a spade the wash of earth was removed, and one of the mounds I found to be nearly as large as that of the Great Geysir. I was able to make out the central bore, but found it blocked with disintegrated sinter.

We pitched our tent between Geysir and Strokr, and cooked our supper on the bridge between the blue pools. In the depths of one we could descry a kettle, which some former traveller had dropped.

It was agreed that we should take turns to watch through the night, so as not to miss an eruption of the Geysir. These eruptions take place now about every third day, and not once in twenty-four hours, as was the wont of Geysir a few years back. He who kept guard was to be employed in digging a trench between the blue ponds and Strokr, which we purposed filling by turning the stream into it.

Strokr went off in the night without being baited, but the Great Geysir remained tranquil.

Next day, Saturday, we spent in filling the well from the pools, as already mentioned. We got on slowly with the trench to Strokr, as the ground is very hard. Ultimately we abandoned our conduit; the future traveller will probably find some traces of it, and I hope that he will continue it, and try the effect of a dose of lukewarm water on the irascible Strokr. During the day the Great Geysir gave false alarms. Before each explosion, a sound like a gong beating in the bowels of the earth gives warning to be on the alert.

We heard this signal thrice, and each time it was followed by a lifting of the water over the bore to heights from two to eight feet, after which it subsided.

Martin shot several plovers in the marshes below Laugar

fjall, and we cooked them at a fire which we made between Strokr and the well. In the evening we drew lots to decide the order in which we were to keep guard. My watch came first, and it was to be followed by those of Mr. Briggs, Martin, and the Yankee.

Mine was over at two o'clock in the morning, and I had gone comfortably to sleep on my air cushion and fox-skins, when a violent concussion of the ground brought me and my companions to our feet.

We rushed out of the tent in every condition of déshabille, and were in time to see Geysir put forth his full strength.

Five strokes underground were the signal, then an overflow, wetting every side of the mound. Presently a dome of water rose in the centre of the basin and fell again, immediately to be followed by a fresh bell, which sprang into the air full 40 feet high, accompanied by a roaring burst of steam. Instantly, the fountain began to play with the utmost violence, a column rushed up to the height of 90 or 100 feet against the grey night sky with mighty volumes of white steam-cloud rolling about it, and swept off by the breeze to fall in torrents of hot rain. Jets, and lines of water tore their way through the cloud, or leaped high above its domed mass. The earth trembled and throbbed during the explosion; then the column sank, started up again, dropped once more, and seemed to be sucked back into the earth.

We ran to the basin, which was left dry, and looked down the bore at the water, which was bubbling at the depth of six feet.

The diameter we found to be 9 feet 6 inches. A plummet sank about 76 feet.

We observed that Strokr and the well threw up clouds of steam during the eruption of the Geysir, and the little blubbering jets on the sandbank were also more active.

But a very few minutes after the explosion, Martin called out, "Where is Mr. Briggs?"

We looked about us, but our fat friend was not to be seen. We shouted, but there was no answer.

"Very odd! said Martin, "this is his watch. He ought to have roused us, and he has vanished; I hope he has not fallen down Strokr!"

We ran in some alarm to the tent, he was not in it, but an exclamation from Martin brought us round to the side opposite that which faced Geysir.

Here we discovered that "Tun of a man fast asleep, the spade by his side, and his head reposing on a heap of turf. We aroused him with "Wake up, old fellow! you are a nice sentinel, you are, sleeping during your watch!"

Mr. Briggs opened his eyes, rubbed them, and looked sleepily round.

"Do you know what you have missed?" I asked.

"Why! Geysir has erupted during your comfortable nap. So you have lost that sight."

"Ay!" Mr. Briggs started to his feet; "Geysir gone off? Then where are all my flannels?"

"Your what?"

66

Why, I tied a couple of shirts, a pair of trousers and some stockings to my fishing line and let them down the mouth of the Geysir at the beginning of my watch. Did any of you see them erupt with the water and the steam?"

We none of us had, and our search for the missing articles on the following morning was without result, so that these portions of my friend's clothing must have been torn to minute shreds and carried off by the wind, or sucked into the bowels of the earth, where they may still be stewing for aught I know to the contrary.

On Sunday morning we baited Strokr twice. The bore is 8 feet in diameter at the top, and 44 feet deep. Below 27 feet it contracts to 19 inches, so that the turf thrown in completely chokes it. Steam then generates; a foaming scum covers the surface of the water, and in a quarter of an hour, it surges up the pipe, allowing one ample time for escape to the edge of the saucer. The fountain then begins playing, sending its bundles of jets rather higher than those of the Great Geysir, flinging

up the clods of turf, which have been its obstruction, like a number of rockets. This magnificent display continues for a quarter of an hour or twenty minutes. The erupted water flows back into the pipe from the curved sides of the bowl. This occasions a succession of bursts, the last expiring effort, very generally, being the most magnificent.

Strokr gives no warning thumps like the Great Geysir, and there is not the same roaring of steam accompanying the outbreak of the water.

Bunsen, who visited this part of Iceland in 1845, ascertained by experiment that water, long boiled, becomes almost entirely free of air; by which the cohesion of the aqueous particles is so much increased that, when it is exposed to a heat sufficient to overcome the force of cohesion, the production of steam is so instantaneous and so considerable as to cause an explosion. To this cause he accordingly attributed the eruption of Geysir and Strokr, which, being in constant ebullition for many hours, are then so freed from air, that the intense heat at the bottom at last overcomes the cohesion of the particles, and an explosion ensues.

The only objection which can be raised to this theory is that the characteristics of Geysir and Strokr are very different. The latter is in constant ebullition, not so Geysir. Now, if air were liberated in great quantities, the surface would be continually boiling; as a matter of fact, the surface, except during an explosion, is perfectly at rest, and scarcely a bubble rises through it.

Now, let an iron tube be bent to the angle of 110, keeping one arm half the length of the other. Let the pipe be filled with water, and the short arm be placed in the fire. The surface of the liquid will remain still and calm for a minute; then the pipe begins to quiver, a slight overflow takes place without any signs of ebullition over the lip of the bore, and suddenly, with a throb, the whole column of water is forced high into the air.

With a tube the long arm of which is 2 ft., and the bore inch, I can send a jet to the height of 18 feet.