Correspondence. 



423 



about 500 feet. In the centre of this immense area, a circular cone 

 ascends to a somewhat greater height than that of the sides. This 

 inner cone is perfectly symmetrical, and of a very abrupt angle, at 

 least forty-five degrees ; its base occupying about a quarter of a mile, 

 or a little more, leaving an uniform open circular space of perhaps 

 200 yards broad all round its base. 



From the summit of this cone, Capt. Miller saw a clear and full 

 stream of transparent vapour issue. So transparent, that it was not 

 perceptible from the sea, nor until he entered the amphitheatre ; this 

 vapour is the only indication of the present activity of the volcano ; 

 but old streams of lava are seen on the side of the cone, specimens 

 of which Capt. Miller brought away with him ; these lava streams 

 are the same material as the cone itself; they are also identical 

 with the causeway, or burst of lava forming the breach leading down 

 to the sea.* 



There is no vegetation of any kind within the amphitheatre, but a 

 few small trees are found on other parts of the Island, which however 

 barren it may have been at one time, is now well wooded. 



Capt. Miller describes the view of the inner amphitheatre as magni- 

 ficent beyond all description, with the gigantic pyramid rising out of 

 the centre to an elevation of 500 feet. Ascending this to about one-third 

 of its height, Capt. Miller found it so steep and difficult, that he was 

 obliged to return. It consists of hard, porous, or loose granular kind of 

 lava of blackish brown colour, with whitish grains of felspar about the 

 size of duck shot imbedded the matrix. Decomposing by the action of 

 the air, the little grains become detached, and falling down the surface 

 of the cone, fill all its crevices and hollows, giving to it the peculiar 

 smooth and symmetrical form which it presents to the view. The outer 

 walls of the crater forming the amphitheatre, are composed of the same 

 material as the cone itself, but of a more solid character, and less sub- 

 ject to decomposition. The causeway or inclined plane, upon which 

 the ascent is made through the breach at the only accessible point, 

 consists of the same material as the cone itself, but is more heavy and 

 compact. It consists of dark blackish lava, with a slightly vitreous 

 lustre, and greyish pearly grains of felspar imbedded in it. This also 

 constitutes the general mass of rocks composing the island. 



To afford an idea of the value of his remarks, and the opportunity he 



* It will be recollected, that at the period to which Dr. Adam's account refers, this mass 

 of rock was quite hot, so as to communicate an almost boiling temperature to the adjoin- 

 ing sea water. 



