VOL. LXXIX.] PHILOSOPHICAL TRANSACTIONS. 533 



axe: at the depth of a foot he found It a little softer, with an oily appearance, 

 in small cells. A little of it held to a burning candle makes a hissing or crack- 

 ing noise like nitre, emitting small sparks with a vivid flame, which extinguishes 

 the moment the candle is removed. A piece put in the fire will boil up a long 

 time without sufi^ering much diminution: after a long time's severe heat, the 

 surface will burn and form a thin scoria, under which the rest remains liquid. 

 Heat seems not to render it fluid, or occupy a larger space than when cold; 

 whence he imagines there is but little alteration on it during the dry months, as 

 the solar rays cannot exert their force above an inch below the surface. He was 

 told by one Frenchman, that in the dry season the whole was a uniform smooth 

 mass; and by another, that the ravins contained water fit for use during the 

 year; but can believe neither: for if, according to the first assertion, it was an 

 homogeneous mass, something more than an external cause must aff^ect it, to 

 give it the present appearances : nor without some hidden cause can the 2d be 

 granted. Though the bottoms of these ramified channels admitted not of ab- 

 sorption, yet from their open exposure, and the black surface of the circumja- 

 cent parts, evaporation must go on amazing quick, and a short time of dry 

 weather must soon empty them; and from the situation and structure of the 

 place there is no possibility of supply but from the clouds. To show that the 

 progress of evaporation is amazingly quick here, at the time he visited it there 

 were, on an average, ■§- of the time incessant torrents of rain ; but from the 

 afternoon being dry, with a gentle breeze, as is generally the case during the 

 rainy season in this island, there evidently was an equilibrium between the rain 

 and the evaporation; for in the course of 3 days he saw it twice, and perceived 

 no alteration on the height of the water, nor any outlet for it but by 

 evaporation. 



Mr. A. takes this bituminous substance to be the bitumen asphaltum Linnei. 

 A gentle heat renders it ductile; hence, mixed with a little grease or common 

 pitch, it is much used for the bottoms of ships, and for which intention it is 

 collected by many, and he conceives it a preservative against the Borer, so 

 destructive to ships in this part of the world. Besides this place, where it is 

 found in this solid state, it is found liquid in many parts of the woods; and at 

 the distance of 20 miles from this about 2 inches thick, round holes of 3 or 4 

 inches diameter, and often at cracks or rents. This is constantly liquid, and 

 smells stronger of tar than when indurated, and adheres strongly to any thing it 

 touches; grease is the only thing that will divest the hands of it. 



The soil in general, for some distance round La Bray, is cinders and burnt 

 earths; and where not so, it is a strong argillaceous soil; the whole exceedingly 

 fertile, which is always the case where there are any sulphureous particles in it. 

 Every part of the country, to the distance of 30 miles round, has every appear- 



