91 
Oxygene and hydrogene in 'J 
the proportions necessary >15*156 
to form water - J 
Hydrogene in excess - - 8*900 
According to the same chemists, 100 parts of 
copal consist of 
Carbon - - 76*811 
Oxygene - - 10*606 
Hydrogene - - 12*583 
or 
Carbon - - 76*11 
Water or its elements - 12*052 
Hydrogene - - 11*187 
From these results, if resin be a definite com- 
pound, it may be supposed to consist of 8 pro- 
portions of carbon. 12 of hydrogene, and one of 
oxygene. 
Resins are used for a variety of purposes. Tar 
and pitch principally consist of resin, in a partially 
decomposed state. Tar is made by the slow com- 
bustion of the fir ; and pitch by the evaporation of 
the more volatile parts of tar. Resins are employed 
as varnishes, and for these purposes are dissolved 
in alcohol 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 solu- 
tion. 
14. Camphor is procured by distilling the wood 
of the Camphor-tree (j haunts camphora\ which 
grows in Japan. It is a very volatile body, and 
may be purified by distillation. Camphor is a 
white, brittle, semitransparent substance, having 
a peculiar odour, and a strong acrid taste. It is 
