70 CARBON. 



with lead, on the floor of which a thin layer of 

 water is put. The combustion of the nitre fur- 

 nishes oxygen to the sulphur, and the sulphuric 

 acid is condensed in the water. It is in this manner 

 that the common oil of vitriol is made: but it then 

 contains many impurities; when freed from these, 

 it is colourless. 



If sulphuric acid be heated in contact with a 

 combustible body, as charcoal or mercury, it loses 

 part of its oxygen, and is then converted into sulphu- 

 reous acid gas, which must be collected over mer- 

 cury, as it is absorbable by water. 



CARBON. 



This elementary body is widely diffused through- 

 out nature. Common charcoal consists of it, mixed 

 with a small quantity of foreign matter. The 

 purest variety of charcoal is lamp black. 



Carbon exists as a constituent principle in all 

 vegetable and animal matters, and remains fixed, 

 after all the volatile parts have been carried off, 

 during the process of combustion. 



Charcoal is very nearly the same, from whatever 

 it has been procured. It is always black and brittle, 

 and exhibits the fibrous structure of the wood. It is 

 not at all liable to change, and hence wood is some- 

 times charred on the outside, when driven into the 

 ground for piles, and similar uses. 



The diamond, a substance so very different in 

 appearance, has been found by experiment to be 

 only crystallized carbon. Diamonds are found only 

 in Asia and Brazil, and always in the alluvial soil. 

 Diamond is the hardest body, and can only be cut 



