COHESION OF LIQUIDS. 149 



remains after the distillation, is still more tena- 

 cious. 



Naphthalin is composed of lOc. 4h. united into 

 1 atom 64. It is a highly tenacious liquid, re- 

 quiring a temperature of 400 for its volatiliza- 

 tion. 



According to Dumas and Laurent, there is a 

 combination of carbon and hydrogen in the ratio 

 of 15c. 4h. (equivalent 94) which has been called 

 paranaphthalin. It is one of the last products 

 from the distillation of coal tar, and is less vola- 

 tile than naphthalin. The atomic weight of sul- 

 phuric acid is 40, and that of naphthalin 64. 

 When 2 equivalents of the former unite with 2 

 of the latter, the compound equivalent is 208 of 

 sulpho naphthalic acid, (according to Faraday) 

 forming a hard and brittle solid, that is soluble 

 in water, alcohol, and oils. 



Naphthalin also forms a dense and tenacious 

 compound with chlorine. With cyanogen, sul- 

 phur, iodine, bromine, &c. it forms dense semi- 

 liquids, the cohesion of which augments in 

 proportion to the increased magnitude of their 

 compound equivalents. 



From the atomic constitution of camphene, oil 

 of turpentine, cloves, peppermint, anise, naphtha- 

 lin, &c. there can scarcely be a doubt that their 

 cohesion, and that of the fixed oils, is greatly mo- 

 dified, if not wholly determined by the number 

 and relative proportions of elementary atoms 



