458 



DISTRIBUTION OF PLANTS. 



kinds were light, fibrous, and spongy throughout, almost like pumice ; 

 other kinds had the vitreous crust, and this too varied, having in 

 some instances a metallic leaden hue; while the lava of the great over- 

 flow before-mentioned, was in a thick layer, very heavy and solid. 

 This indeed seemed the only feature that was tolerably constant in 

 these overflows ; that the solidity seemed much in proportion to the 

 thickness of the layer. 



The large lake having so long remained deeply sunk below its 

 banks, the opportunity seemed favorable for approaching it; and on 

 setting out, I was soon joined by Lieut. Colvocoressis. Notwithstanding 

 the length of time since the last overflow, the lava-surface on the way 

 proved very hot ; but the heat did not increase in advancing ; and we 

 succeeded in reaching the brink. We were here thirty feet above the 

 surface of the molten lake; in its wide extent, presenting an accumu- 

 lation of heat that threw into insignificance all fires of fuel. Facing 

 the fluid was impossible, except for an instant ; and a view could only 

 Ije obtained by approaching the brink backwards, turning with an 

 even motion around, and quickly retreating ; to again repeat the move- 

 ment. It is true, the lava-spouts were close at hand, along this margin 

 of the lake ; but the heat seemed scarcely less intense throughout ; and 

 even where the surface was darkest and most quiet, the lava-cliff at 

 the line of contact was heated beyond the grade of redness almost to 

 whiteness. The condition of things lower down and underneath 

 could not be known ; but independent of the warning of the previous 

 evening, the banks were obviously unreliable : the currents too were 

 not altogether constant, but a slight divergence once took place to- 

 wards the spot on which we were standing; which was besides directly 

 over the seat of fiercest action. The perpetual commotion did not 

 however produce noise enough to drown conversation ; according 

 entirely with my previous experience at greater distances. 



On our way back, the smaller lake was observed to be widely-over- 

 flowing ; and at one time we were apprehensive, lest the fluid should 

 extend from cliff to cliff and intercept our return ; but the point of 

 danger was passed without difficulty. On gaining the " black ledge," 

 a muttering noise was heard, which at first seemed to come from the 

 bottom of the Crater ; but a streak of rising dust soon revealed the 

 descent of a slight avalanche down the steep Western bank. 



After ascending out of the Crater, I was detained at the encamp- 

 ment by rain ; which continued falling rather steadily for some hours, 



