hones. 



358 , ALUM MINES OF AUBIN. 



of the hill uninjured. They run horizontally about a 

 third of the way down the hill. The works had not been 

 carried very deep before the fire, but they occupied a con- 

 fiderable length on the outcrop. 



The space deranged and altered by the fire exhibits nearly 

 an OTal figure. The shorter axis does not exceed 70 met. 

 [76 yards] ; but the greater, which is horizontal, may be 

 150 met. [164 yards]. The surface cannot be estimated at 

 more than 60 ares [148 acres]. The whole of it has ceased 

 to form a continued plane with the slope of the mountain, 

 "which is about 40*^ ; and exhibits a depression pretty ex- 

 actly resembling in figure the stern of a boat. Part of this 



, surface is coTcred with solid aluminous incrustations, which 



resist the action of the rain in some degree, or are repro- 

 duced immediately after. It must be a rich mine, though 

 not at present worked. 



Mine of Bourl- The mine of Bourlhones is the least of the four. It is 

 half way up the hill that faces the mine of Buegne, and 

 consequently in the same valley. Their distance from each 

 other in a straight line is about 500 met. [546 yards.] 



The fire that formed it has notcontinued above ten years. 

 It is fed at the expense of a single seam of coal several yardg 

 thick, and inclining 30^ or 40? east, consequently oppo- 

 site to the slope of the hill. 



The coal had not been worked to any extent, when it 

 took fire. The combustion has not yet reached its highest 

 degree of activity. The surface of the ground is partly 

 covered with grass, partly sunk down, cracked, and torre- 

 fied. Copious vapours of water, sulphur, and bitumen, 

 issue from it. Its shape is nearly circular, and it may be 

 estimated at 30 ares [74 acres]. The aluminous salts are 

 very abundant, but only in certain places ; though by proper 

 management their formation may be accelerated in others. 

 No attempt has yet been made to work it. 



Produce of the From the two mines, that are worked by two companies 

 of adventurers, near 17000 myriagr. [167 tuns] of alum 

 were made in 1809, which sold for ^abput 120000 fr, 

 ' [^5000]. 



VII. Th(x 



mines. 



