532 PHILOSOPHICAL TRANSACTIONS. [aNNO I789. 



a strong sulphureous smell, sometimes disagreeable. This smell is prevalent in 

 many parts of the ground to the distance of 8 or ] miles from it. 



This point of land is about 2 miles broad, and on the east and west sides, from 

 the distance of about half a mile from the sea, falls with a gentle declivity to it, 

 and is joined to the main land on the south by the continuation of the Mangrove 

 swamps ; so that the bituminous plain is on the highest part of it, and only 

 separated from the sea by a margin of wood which surrounds it, and prevents a 

 distant prospect of it. Its situation is similar to a Savannah, and, like them, it is 

 not seen till treading on its verge. Its colour, and even surface, present at first 

 the aspect of a lake of water ; but probably it got the appellation of lake when 

 seen in the hot and dry weather, at which time its surface to the depth of an inch 

 is liquid, and then from its cohesive quality it cannot be walked on. It is of a 

 circular form, and about 3 miles in circumference. At the first approach it ap- 

 peared a plane, as smooth as glass, excepting some small clumps of shrubs and 

 dwarf-trees that had taken possession of some spots of it; but when Mr. A. had 

 proceeded some yards on it, he found it divided into areolae of different sizes and 

 shapes : the chasms or divisions anastomosed through every part of it ; the sur- 

 face of the areolae perfectly horizontal and smooth ; the margins undulated, each 

 undulation enlarged to the bottom till they join the opposite. On the surface the 

 margin or first undulation is distant from the opposite from 4 to 6 feet, and the 

 same depth before they coalesce ; but where the angles of the areolae oppose, the 

 chasms or ramifications are wider and deeper. When he was at it, all these 

 chasms were full of water, the whole forming one true horizontal plane, which 

 rendered the investigation of it difficult and tedious, being necessitated to plunge 

 into the water a great depth in passing from one areola to another. The truest 

 idea that can be formed of its surface will be from the areolae and their ramifica- 

 tions on the back of a turtle. Its more common consistence and appearance is 

 that of pit-coal, the colour rather greyer. It breaks into small fragments, of a 

 cellular appearance and glossy, with a number of minute and shining particles in- 

 terspersed through its substance ;, it is very friable, and, when liquid, is of a jet 

 black colour. Some parts of the surface are covered with a thin and brittle scoria, 

 a little elevated. As to its depth he could form no idea of it ; for in no part 

 could he find a substratum of any other substance ; in some parts he found cal- 

 cined earth mixed with it. 



Though he smelt sulphur very strong on passing over many parts of it, he 

 could discover no appearance of it, or any rent or crack through which the 

 steams might issue; probably it was from some parts of the adjacent woods: for 

 though sulphur is the basis of this bituminous matter, yet the smells are very 

 different, and easily distinguished, for its smell comes the nearest to that of 

 pitch of any thing. He could make no impression on its surface without an 



