456 COMPOUND PRODUCTS. CHAP. I. 



same, In the plants examined by Proust the pro- 

 portion was found to be as follows, the quantity of 

 wood charred being represented by unity : 



Black Ash , 0-25 



Guaiacum O*24 



Pine. O-20 



Green Oak O'2O 



Heart of Oak O'lQ 



Wild Ash 0-17 



White Ash 0'17 



Properties. Charcoal is insoluble in water, of which how* 

 ever it absorbs a portion when newly made, as also 

 of atmospheric air. It is incapable of putrefaction. 

 It is not altered by the most violent heat that can 

 be applied, if all air and moisture are excluded ; 

 but when heated to about 80O it burns in atmos- 

 pheric air or oxygene gas, and if pure, without 

 leaving any residuum. It is regarded by chemists 

 as being a triple compound, of which the ingre- 

 dients are carbon, hydrogene, and oxygene. 



Uses. Charcoal is of great utility both to the chemist 



and artist as a fuel for heating furnaces, as well as 

 for a variety of other purposes. It is an excellent 

 filter for purifying water. It is a very good tooth 

 powder ; and is also an indispensable ingredient in 

 the important manufacture of gunpowder. 



