36 THE IRON ORE DISTRICT OF EAST TEXAS. 



average being probably fifty-two bushels ; that is retorts produce from twenty 

 per cent to thirty per cent more charcoal than kilns, and from thirty-five per 

 cent to sixty per cent more charcoal than meilers from the same variety of 

 wood. It is necessary in some forms of retorts to reduce the size of wood 

 much smaller than is used in kilns. This is done at an expense of labor, but 

 produces a more uniform size and more regularly carbonized product. It is 

 also possible to collect a larger proportion of the vapor which produces the 

 by-products from retorts than from kilns, and a smaller amount of wood be- 

 ing under treatment, retorts permit of better control and a more perfect car- 

 bonization than kilns. 



A tradition among colliers is that charcoal made under dirt covers is of a 

 superior quality to that made either in kilns or retorts. This should not be 

 the case except, possibly, in so far as the turf covering, following the shrink- 

 age of the pile of wood as it carbonizes, prevents, to a certain extent, over 

 carbonization; but the percentage of imperfectly charred wood, or "brands," 

 is generally greater in meilers than in kilns or retorts. The control given by 

 a practically tight masonry structure or a perfectly tight metallic one should 

 permit of producing the grade of charcoal desired, and much of the failure 

 to obtain satisfactory results is undoubtedly due to the operators. 



Michigan is the largest producer of charcoal pig iron in the United States, 

 its output for 1889 being 234,817 net tons, and the charcoal for producing 

 almost all of its iron -was made in masonry kilns or retorts. In Alabama, 

 which ranks next to Michigan as a producer of charcoal iron, kilns are not so 

 largely used, and considerably more than one-half of the charcoal used there 

 last year was made in meilers. 



The utilization of the pyroligneous acid which is condensed from the vapors 

 resulting from charcoal kilns or retorts is in the direction of producing ace- 

 tates for dyeing and for methylic alcohol. The practicability of such utiliza- 

 tion depends largely upon the location of the plant, for unless a market for 

 the by-products is accessible it will not pay to collect them. The quantity of 

 alcohol and acetates obtained from a cord of wood also varies greatly, in ac- 

 cordance with the kind of wood used, and therefore before taking up the pos- 

 sible utilization of the by-products, the cheapness of the production of char- 

 coal, the character of the wood used, and the possible markets for the by- 

 products must be carefully considered. 



True economy will dictate that in any enterprise which is planned to con- 

 sume a large amount of charcoal, the process should be mapped out which 

 will obtain the greatest amount of fuel from a given acreage of wood, and 

 hence coaling under dirt covers (that is, in meilers or pits) would not com- 

 mend itself to those who favor protection of the timber areas of the State. 

 Not only do kilns or retorts produce a larger amount of charcoal from the 



