322 CHEMISTRY. 



bolic acid (phenol), a substance of great value as a disin- 

 fectant. By acting on phenol with nitric acid, a beautiful 

 yellow dye is obtained called picric acid. The pitch which 

 is left after distilling off these oils is much used in Europe 

 as a cement for refuse coal-dust. The mixture thus made 

 is cut up into cakes for fuel. 



441. Nature's Products from Bituminous Coal. The re- 

 sults of the dry distillation of bituminous coal by art have 

 their counterpart in nature. Volcanic heat is the agent. 

 The anthracite coal is very much like the coke formed in 

 the retorts of the gas-works, except that immense pressure 

 has condensed and hardened it during the action of the 

 heat. Then we have inflammable gases issuing from crev- 

 ices of rocks, answering to the illuminating gas produced 

 by art. The oil of coal-tar has its representatives in nat- 

 ure in the naphtha that oozes out of the ground in Persia, 

 and in the mineral tar found in France as well as in Persia. 

 Then, to compare with the pitch, the artificial asphaltum 

 obtained from the coal-tar, we have the natural asphal- 

 tum of the Dead Sea of Judea, found also in other seas in 

 Asia. 



442. Petroleum. Petroleum has been known from a very 

 early period in the history of the earth, but it was reserved 

 for American enterprise to discover the inexhaustible sup- 

 ply beneath the surface. Evidences of the use of petro- 

 leum are found near the ruins of Nineveh and Babylon ; 

 the springs of Rangoon, in India, have been worked for 

 ages ; and in our own country the Indians collected petro- 

 leum for various purposes, chiefly medicinal. In 1854 a 

 company was formed for collecting "rock oil" at Oil 

 Creek, Pennsylvania ; but the process of gathering it from 

 ditches in blankets and squeezing it into tubs was too ex- 

 pensive. In 1858 Colonel Drake began to bore an artesian 

 well for oil, believing that that which oozed out of the 



