C 89' ] 



or of 



Carbon 75,944 



Oxygene and hydrogene in the pro- 



ro-l 

 erj 15 ' 



portions necessary to form water 

 Hydrogene in excess - 8,900 



According to the same chemists, 100 parts of co- 

 pal consist of 



Carbon 76,8 1 1 



Oxygene % 1O,606 



Hydrogene - 1 2,583 



or, 



Carbon - 76,811 



Water or its elements - - 12,052 

 Hyrogene - 11,137 



From these results, if resin be a definite com- 

 pound, it may be supposed to consist of 8 proportions 

 of carbon, 12 of hydrogene, and 1 of oxygene. 



Resins are used for a variety of purposes. Tar 

 and pitch principally consist of resin, in a partially de- 

 composed state. Tar is made by the slow combustion 

 of the fir ; and pitch by the evaporation of the more 

 volatile parts of tar. Resins are employed as var- 

 nishes, and for these purposes are dissolved in alco- 

 hol or oils. Copal forms one of the finest. It may 

 be made by boiling it in powder with oil of rosemary, 

 and then adding alcohol to the solution. 



14. Camphor is procured by distilling the wood 

 of the camphor tree (Laurus Camphor a,} which grows 

 in Japan. It is a very volatile body, and may be pu- 

 rified by distillation. Camphor is a white, brittle, 

 semitransparent substance, having a peculiar odour, 



N 



