TRAVELS IN ICELAND. 



67 



They afterwards went farther, with a view to arrive at the heart 

 of the cavern, which grows considerably narrower, till it is not 

 more than a foot in height, by even a less width. The cave 

 called the Fortification from the rampart already mentioned, is 

 fifty fathoms long, while its greatest width is a fathom and a 

 quarter, and its height nearly the same. It is so narrow and low 

 in the middle, that one can scarcely pass through it on one's knees , 

 and when our travellers thought themselves at the end, they found 

 that it again widened into the form it had before; towards the 

 place where it becomes so narrow, the soil ascends considerably, 

 and afterwards slopes down : at the end of this declivity, our tra- 

 vellers found a lake of fresh water, the bottom of which was fro- 

 zen. They passed it with the water up to their knees, and at 

 every step they had additional proof that the whole of these 

 caves had been formed by the melting or dissolution of stones. 

 The great channel being at length blocked up for some time, and 

 the fire not being able to rind a vent, acted upon the sides, and 

 melted the rftore dissoluble earths aud stones ; but before the 

 fiery matter could thus find an outlet, the great canal had forced 

 its way, and had ceased to have any action on the caverns. The 

 narrow passage that our travellers found, proves, however, that 

 the fire did not operate with the same force upon the rocks in 

 that spot, or could not reduce them so easily as the others, be- 

 cause they were of a harder and more resisting nature. 



On leaving the cavern of the Fortification, our travellers pro- 

 ceeded farther into the Sourther ; they had a difficult route, on 

 account of the rocks which were detached from the top, and at 

 times were obliged to pass on their hands and knees through 

 intermediate spaces rilled with water, and soaked through by the 

 drops that filtered from the top. Some of the detached fragments 

 of the rock were upwards of five feet six inches in height: at length, 

 after many attempts to advance, they perceived some rays of 

 light penetrating through an aperture in the roof, and on reach- 

 ing this spot they found above the hole a heap of ice and snow, 

 which had remained since winter. They purs ued their road to a 

 good distance, when they perceived an aperture; but before reach- 

 ing it, they found a wall that divided the cavern into two equal 

 parts ; this wall was below the hole, but it had fallen to decay. 

 The cavern afterwards branched off into two galleries, the left of 

 which was twenty feet in length, and the right much more; while 

 in both of them they every where observed the effects of fire. The 

 gallery to the left became at last so narrow, that they were obliged - 

 to creep on their hands and knees ; and at this^part they smelt a 

 kind of fetid exhalation, propelled by the air of the subterraneous 

 channels : it was an infectious miasma, similar to that which arises 



