[ 274 ] [Book VI. 



CHAP. XLII. 



NAPHTA, PETROLEUM, BARBADOES TAR, &c. 



Nature and Properties of Napbta. Burning Fountains, Petroleum.*** 

 Mineral Pitch, or Barbadoes Tar. Lake Afpbaltes,Afpbaltum' y 

 ho--w collected. Elaftic Bitumen. Component Principles of tbefe 

 Sub/lances. 



ALL thefe fubftances are of the bituminous kind, 

 and are, indeed, all of the fame nature, but dif- 

 fer in confidence. NAPHTA is an oily fluid, which, in 

 its greateft degree of purity, is nearly colourlefs, is 

 extremely volatile and fubtile, and fo light as to float 

 even on fpirits of wine. It has a ftrong oppreffive 

 fmell, and evaporates fpontaneoufly. Like other oils, 

 it burns with fmoke. It does not congeal at o of Fah- 

 renheit. It is faid to be gathered at the furface 

 of certain wells in Perfia, and is rarely found in 

 Europe. 



The vapour of naphta, which ifiues through the 

 crevices of the earth, is generally fuppofed to be 

 the caufe of the flame which is fometimes obferved 

 on waters, fountains, &c. At Chittagon, in the Eaft 

 Indies, there is a fountain which burfts into flame of 

 its own accord, whenever it has been extinguished by 

 accident ; this fountain has its deity and its priefts ; 

 and fome Europeans, fufpecting the whole to be a 

 pious fraud, pulled down the wall, &c. but found that 

 the vapour actually kindled fpontaneoufly when put 

 out. It is pofllble, however, that this flame may be 

 fed by inflammable air inftead of naphta. 



PETROLEUM, which is of a thicker confiftence, and 



more 



