Scientific Lectures. 219 



with a final residue of the mineral matters present, the ashes. The 

 second occurs uuder water or beds of wet sand or clay. It develops 

 a carbonaceous product which is our peat and coal. 



Every piece of timber which is employed in our structures is 

 gradually undergoing deterioration ; and the timber of our forests is 

 rapidly disappearing from being worked up into structures, and 

 subsequently undergoing decay. The railroad and telegraph com- 

 panies are making sad havoc in our forests. 



It is estimated that $3,000,000 per annum are spent in replac- 

 ing decayed telegraph poles alone, while railroad sleepers require a 

 far larger amount. 



In Europe, special attention is given to this fact ; and departments 

 of forests have been organized. Every land owner who cuts down 

 trees, is compelled by law to plant a certain number of trees in their 

 place. 



In the early times it was though that these forests were so vast 

 that they could never be exhausted by the railroad companies and 

 telegraph companies. But now the attention of the government has 

 been directed to the subject. 



Yarious methods to prevent this kind of combustion have been 

 devised : methods for preserving timber. 



The best of these methods is to impregnate the logs with oil of coal 

 tar. Coal tar contains carbolic acid, which prevents the decay. The 

 durability of the timber is increased fourfold. Railroad sleepers, 

 which, without the preparation, decay in six to nine years, in some 

 cases, with the preparation, lasted forty (40) years. 



Another form of destruction is from the attack of animals. In 

 the southern waters the teredo navalis attacks the bottom of ships, 

 and the timber of piers ; but it never touches the wood if it is impreg- 

 nated with carbolic acid. 



Respiration. 



Another form of combustion is respiration. Respiration is animal 

 combustion. Combustion takes place in the animal economy and 

 develops muscular heat. Our thoughts, our plans, our life, and our 

 activity, are the results of combustion. 



It is owing to combustion that we are able to exert activity. It is 

 owing to combustion of the nervous matter that we are able to think. 

 It is that which blood gives to the tissues. A man consumes fourteen 

 ounces of carbon in his food every day, or 300 pounds per annum. 

 This carbon is converted into carbonic acid, just as though it were 

 burned in the fire. 



