148 COHESION OF LIQUIDS. 



By adverting to the second table, it will be 

 found that camphene, or camphogen, is composed 

 of lOc. to 8h. united into 1 compound atom, the 

 weight of which is 68, compared with hydrogen : 

 whereas, the essence of lemon is composed of 5c. 

 to 4h. making a proximate atom equal to 34, or 

 one-half that of camphene. The consequence 

 of which is, that the latter is much more volatile 

 than the former, though their specific gravities 

 are nearly the same. Camphene requires a tem- 

 perature of 312 F. to make it boil, while the 

 essence of lemon is highly volatile like naphtha. 

 Camphene is the principal ingredient in oil of 

 turpentine and camphor, both of which are oxides 

 of camphene. Common camphor is composed of 

 1 atom camphene to 1 of oxygen. There is also 

 an artificial camphor, composed of hydrochloric 

 acid 1 atom, united with 1 of camphene. While 

 3 atoms of water and 1 of camphene make the 

 hydrate of camphene ; and 5 atoms oxygen to 1 

 of camphene, camphoric acid. Petrol ene, which 

 is obtained from petroleum by distillation, ac- 

 cording to Boussingault, is composed of carbon 

 and hydrogen in the same proportions as cam- 

 phene ; but its proximate atom being just double 

 that of camphene, corresponding with the diffe- 

 rence between the specific gravity of their va- 

 pours, it possesses the consistence of a fixed oil, 

 requiring a temperature of 536 F. to convert it 

 into vapour. The product (asphaltine), which 



