Page:The Boy Travellers in Australasia.djvu/61

Rh another from the circumference to the centre of the lake. Every minute or so the lava in the centre of the lake bulged up and broke into an enormous bubble or wave which sometimes rose twenty or thirty feet into the air, and then broke and scattered just as you see a bubble breaking in a kettle of boiling paste or oatmeal porridge. I know the comparison is a homely one, but I can't think of anything that will better describe what we saw.

"The bank of the lake down near where the lava came against it was red-hot, and so you may imagine if you can a mass of liquid fire rolling and surging against a solid one. One of the lakes was much more agitated than the other, and the liquid lava seemed to break upon its sides very much like a sea upon a rocky shore. Owing to the half-plastic condition of the lava, it could not break into surf and spray like the waves of the ocean, but it made a dull roar, something like that of the Pacific on the beach near San Francisco just after the subsidence of a storm.



"The surface of the lava changes its height from time to time. The guide said it occasionally rose until it overflowed the sides of the basin enclosing the lakes, and formed streams that spread out over the level area of the great crater. Sometimes it sank so that it was fully four hundred feet from the edge of the rim down to the lava; but whether it was high or low, there was never a time when it was wholly inactive.

"The guide called our attention to cones which had formed on the rim of the lake; they were caused by the cooling of the lava around vent-holes, and as successive jets of lava were thrown up and cooled