MAUN A LOA. 127 



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 tread- 

 ing 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 stifling to bear. I shall not soon forget my 

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

 capacity of the lake, of which some account will be given hereafter. 

 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 crystals, adhering 

 to their sides ; while on the bank itself, some specimens of sulphate of 

 copper, in beautiful blue crystals, were found. 



From many places on the black ledge a bluish smoke was seen 

 issuing, smelling strongly of sulphur, and marked by an efflorescence 

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

 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, we 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 

 distance to be passed over in the ascent from the black ledge, which 

 was found six hundred and sixty feet below the rim. 



