58 BURNING OR OXIDATION 



nevertheless the intense heat affects the wood and changes 

 it into new substances, one of which is charcoal. 



The wood which smolders on the hearth and in the stove 

 is charcoal in the making. Formerly wood was piled in 

 heaps, covered with sod or sand to prevent access of oxygen, 

 and then was set fire to; the smoldering wood, cut off from an 

 adequate supply of air, was slowly transformed into charcoal. 

 Scattered over the country one still finds isolated charcoal 

 kilns, crude earthen receptacles, in which wood thus deprived 

 of air was allowed to smolder and form charcoal. A student 

 can make in the laboratory sufficient charcoal for art lessons 

 by heating in an earthen vessel wood buried in sand. The 

 process will be slow, however, because the heat furnished by 

 a Bunsen burner is not great, and the wood is transformed 

 slowly. 



A form of charcoal known as animal charcoal, or bone 

 black, is obtained from the charred remains of animals rather 

 than plants, and may be prepared by burning bones and 

 animal refuse as in the case of the wood. 



54. Matter and Energy. When wood is burned, a small 

 pile of ashes is left, and we think of the bulk of the wood as 

 destroyed. It is true we have less matter that is available for 

 use or that is visible to sight, but, nevertheless, no matter has 

 been destroyed. The matter of which the wood is composed 

 has merely changed its character , some of it is in the condition 

 of ashes, and some in the condition of invisible gases, such as 

 carbon dioxide, but none of it has been destroyed. It is a 

 principle of science that matter can neither be destroyed nor 

 created ; it can only be changed, or transformed, and it is our 

 business to see that we do not heedlessly transform it into 

 substances which are valueless to us and our descendants; 

 as, for example, when our magnificent forests are recklessly 

 wasted. The smoke, gases, and ashes left in the path of a 



