140 Forestry Quarterly. 



chars with high heat very irregularly. Only when the water is 

 driven off do progress and heat become normal. 



The hygroscopic water is much more easily driven off than the 

 sap. 



4. In sour wood, in spite of a very high degree of heat, charring 

 progresses slowly. 



5. The lowest heat and the slowest coaling is shown by well- 

 dried wood. 



If green, wet, sour or rotten wood is mixed with dry wood in 

 a meiler so that one of these qualities is placed on one side of the 

 meiler, the dry wood on the other side, the progress of coaling is 

 more rapid in the dry wood, because the steam developed on the 

 other part works on it. 



7. Rotten or doty wood, even when mixed with sound wood, 

 chars more quickly than the latter. 



8. Carburetted hydrogen is developed in any charring process, 

 the more the higher the smouldering heat; the more steam is de- 

 veloped, the poorer the quality of the wood. It does not produce 

 any injury if it can escape through the smoke holes unhindered. 

 If it is impeded here, then it attacks first the ready charcoal; 

 finally it may explode. 



9. If under presence of steam and glowing carbon there is a 

 formation of carbon oxyd gas, this damages the process and the 

 result. In a fully finished meiler the coal is deteriorated, the coal 

 crumbles into small pieces, becomes soft and light. 



10. In these respects the different species show little difference. 



11. Hard woods produce more severe explosions than conifers 

 and light woods. Frequency of explosion, however, is a charac- 

 teristic of conifers, especially fir. 



The notion that split wood should be set with the split side to 

 the interior was found of not the slightest value. 



Placing the wood in lying position in a standing meiler was 

 found only to be more expensive, otherwise without objection. 



The ease of charring — which, with the exception of the conifers, 

 denotes also high yield and good quality — the following qualifi- 

 cation of species was found : 



Very good coalers : oaks, beech, ash, maple, elm, birch ; difficult, 

 but large yield: spruce, fir, pine; slow coaling and small yield: 

 willow, poplar, basswood. 



