136 MAUN A LOA. 



risen above the ledge, altogether concealing it from view, and that it 

 had entirely fused its surface. The appearances did not satisfy me 

 that this had been the case, nor did the supposition account for the 

 fact, that none had been collected within the last few months ; besides, 

 it might be supposed that some portion of the former accumulation 

 ought to have been discoverable, which it was not. 



To walk on the black ledge is not always safe, and persons who 

 venture it are compelled for safety to carry a pole and feel before 

 they tread over the deceitful path, as though they were moving on 

 doubtful ice. The crackling noise made in walking over this crisp 

 surface (like a coating of blue and yellow glass) resembles that made 

 by walking on frozen snow in very cold weather. Every here and 

 there are seen dark pits and vaulted caverns, with heated air rushing 

 from them. Large and extended cracks are passed over, the air 

 issuing from which, at a temperature of 180°, is almost stifling; 

 masses are surmounted that it would seem as if the accumulated 

 weight of a few persons would cause to topple over, and plunge the 

 whole into the fiery pool beneath. 



On approaching the large lake at the southern end of the crater, 

 the heat becomes almost too stiflinor to bear. I shall not soon forjjet 

 my employment therein, in measuring a base to ascertain the extent 

 and capacity of the lake, of which some account will be given here- 

 after. At about two-thirds of the distance from the north end are 

 extensive sulphur banks, from the fissures in which much steam is 

 continually escaping : in these fissures are seen many beautiful crys- 

 tals, adhering to their sides; while on the bank itself, some specimens 

 of sulphate of copper, in beautiful blue crystals, wei-e found. 



From mai:iy places on the black ledge a bluish smoke was seen 

 issuing, smelling strongly of sulphur, and marked by an efflore- 

 scence of a white tasteless powder among the cavities : this it was 

 difficult to detach without scalding the fingers. There were many 

 cracks where our sticks were set on fire, and some places in the 

 vaulted chambers beneath, where the rock might be seen red hot. 



The black ledge is of various widths, from six hundred to two 

 thousand feet. It extends all around the cavity, but it is seldom 

 possible to pass around that portion of it near the burning lake, not 

 only on account of the stifling fumes, but of the intense heat. In 

 returning from the neighbourhood of the lake to the point where we 

 began the ascent, Ave were one hour and ten minutes of what we 

 considered hard walking ; and in another hour we reached the top of 

 the bank. This will probably give the best idea of its extent and the 



