304 THE LIFE OF JAMES D. FORBES. [CIIAI>. 



we scrambled to the top. . . . The crater seemed very 

 like that of 1826, but filled up on the N.E. side, whence 

 the lavas of 1832, 1833, 1834, and 1839 flowed, and it 

 was also less deep. . . . We were surprised and delighted 

 to see a cone in the -centre resembling a blast furnace, 

 which continually ejected stones arid fragments ofjlayro, 

 while another opening was emitting a steady liquid 

 current of lava 15 or 20 feet wide. I went down the 

 crater to examine it more closely. Its velocity 1 esti- 

 mated at one foot per second, and it was consequently 

 in an extremely liquid state. I carefully compared the 

 phenomena presented by its surface with those presented 

 by the surface of a glacier, but not altogether with effect, 

 for the resemblance failed : firstly, on account of its great 

 liquidity ; secondly, on account of a crust which forms 

 as the surface cools, and which, being then broken up by 

 the liquid pressure below, produces peculiarly irregular 

 and fantastic appearances. 



'Nevertheless, I observed: 1. That the cracks which 

 form in the dark-coloured slag as the stream spreads 

 itself abroad, resemble the radiating fissures of a glacier 

 under similar circumstances, and are well marked by the 

 liquid fire, shining red through them. 



*2. That the slag, where solidified, presented furrows 

 along the surface, parallel to the direction of the structure 

 lines in glaciers, i.e. inclining slightly from the sides 

 towards the centre of the current. 



* 3. That where the lava, having become viscid, forced 

 itself through the obstacles of its slag, it fell like a paste, 

 streaky and drawn out in the direction just mentioned. 



' The lava filled the bottom' of the crater, with the 

 exception of a large cone in the centre, whose fantastic 

 form could be fitfully seen through the smoke. It from 

 time to time ejected red-hot tears of lava, and cinders, 

 which fell to windward, after rising often as high as the 

 exterior walls of the great crater. The sound which 

 accompanied each explosion was not unlike the roar of 

 a blast furnace, to which, indeed, the whole phenomenon 

 had the most striking resemblance : and when 



