150 Mr. HatchettV Obfervations on Bituminous Subftancts, 



the letter B, has been found during the laft three years in a rivulet 

 which runs at thetbafe of Mam tor, from Weft to Eaft, at a fmall 

 diftance from Odin mine. — The varieties of it, in my poffeflion, are 

 as follow : 



SPECIES the SECOND. 



B, No. 1. 



Elastic bitumen, which, recently cut, exactly refembles fine 

 clofe cork in colour and texture, but, by the air, in a few days it 

 becomes of a pale reddifli brown. — This forms a thin coat, which 

 completely covers a mafs of elaftic bitumen, which is foft, and of a 

 browniih olive colour, like A, No. 9. 



B, No. 2. 

 The fame, excepting that the coat or cruft is much thicker. 



B, No. 3. 



The fame, but the coating is thicker than that of No. 2, and the 

 brownilh olive- coloured bitumen much lefs in quantity. 



B, No. 4. 



The fame, excepting that the greater part of the mafs refembles 

 cork, fo that only a very fmall nucleus of the brown bitumen 

 remains*. 



B, No. 5. 



The fame, excepting that the bitumen, which is coated, is in the 

 ftate of afphaltum. 



The fpecific gravity of this fpecimen is 0,9881. 



* One of the fpecimens in my poflcflion, fimilar to B, No. 4. weighs between 

 13 and 14 pounds. 



6 B, No. 6. 



