112 QQARTERLY JOURNAL 



CHARCOAL— ITS PROPERTIES AND USES. 



This substance has excited great attention of late in some por- 

 tions of the country, although no accurate experiments have yet 

 been made to test its value as a manure. In theory, it is certain 

 that it possesses properties which are calculated to render it a very 

 valuable substance in agriculture. And this arises from a power 

 not peculiar to charcoal. All porous bodies have the property of 

 absorbing the different gases in greater or less quantities. Charr 

 coal, after it has been heated to redness^ and cooled without being 

 exposed to the air, will absorb ninety times its own volume of ammo- 

 niacal gas, and considerable quantities of others. If heated and 

 cooled under water, and then placed in a confined portion of at- 

 mospheric air, it will absorb all the oxygen and leave pure nitro- 

 gen. Now, upon this property of absorbing gases depends its 

 use as a manure. In itself, it has no valuable properties. It is 

 one of the most indestructible of substances. Exposed to heat of 

 the greatest intensity, if air is excluded, it suffers no change. Mois- 

 ture has no effect upon it, and there is no chemical agent which 

 will act upon it. It has been said by some writer, that, after be- 

 ing in the ground for several years, it becomes converted into a 

 sort of coaly earth. But, on the other hand, it is a well known 

 fact that fence posts are often charred at the bottom, in order to 

 preserve them from rotting, and it succeeds for a great number of 

 years. In this case, no such change can have taken place. It 

 is, at any rate, very doubtful if it is ever converted into earth, or, 

 of itself, furnishes any food for plants. But it does absorb gases, 

 and by the powerful condensing force which all porous bodies pos- 

 sess, they are made ^olid in the pores of charcoal. One cubic 

 inch of charcoal will condense ninety cubic inches of ammonia, or 

 thirty-five of carbonic acid. And, holding it with all this force, 

 how are they to give it off to plants '? One class of theorists will say, 

 that the vital power of the plant can separate it. But it is locked up 

 in the pores of the charcoal, where not even the most minute fibre 

 of the roots can penetrate. Others say, it is by the power of fix- 

 ing gases that it does good, but they do not account for the giving 

 them out. What then is it 1 Let us look a moment at another 

 fact. 



