ON BASALTS, &C. X9S 



Grains* 



1. Water flightly acid ----- 3 



2. Thick brown oily bitumen, very {imilar to that which 

 was obtained from the Bovey coal, but poffeffing 

 flightly the odour of vegetable tar - - - 45 



3. Light fpongy coal ----- 23 



4. Mixed gas, eompofed of hydrogen, carbonated hydro- 

 gen, and carbonic acid, (by computation,) - 29. 



The coal yielded about three grains and a half of afhes, 

 which confifted of alumina, iron, and filica, with a trace of lime. 



B. The bitumen was not affected by being long digefted in 

 boiling diftilled water. 



C. By digesting 100 grains in lixivium of pure potafli, a 

 brown folution was formed ; this was faturated with muriatic 

 acid, and a brown refinous precipitate was obtained, which, 

 weighed 21 grains. 



D. A portion was digefted in nitric acid : at firft, much 

 nitrous gas was evolved, and, after the digeftion had been con- 

 tinued for nearly 48 hours, a part was diffolved, and formed 

 an orange-coloured folution, which did not yield any precipi- 

 tate, when faturated by the alkalis, or by lime; the colour only 

 became more deep, and, by evaporation, a yellow vifcid fub- 

 flance was obtained, which was foluble in water. The above 

 nitric folution poffefled every property of thofe nitric folutions 

 of refinous fubftances which 1 have mentioned in a former 

 paper. * 



E. The benzoic and fuccinic acids were not obtained from 

 this fubftance, by any of the methods ufually employed. 



F. Alcohol almoft immediately began to a£t upon this bitu- 

 men ; and, being added at different times, gradually diffolved 

 a confiderable part of it. The folution was reddiOi-brown, 

 and has a refinous odour ; by the addition of water it became 

 milky, and, by evaporation, afforded a dark brown fubftance, 

 which had every property of relin, whilft the refiduum left 

 by the alcohol poffeffed thofe proporties which characterize 

 afphaltum. 



The following analyfis was then made, to difcover the pro- 

 portions of the component ingredients. 



* Phil. Tranf. for 1804, p. 198. 



2 ANALYSES 



