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A Burning Question. 



Sound Beach, Connecticut. 

 Dr. Frederick H. Getman, 

 Stamford, Connecticut. 

 Mr. Dear Dr. Getman : 



Will you kindly inform me for pub- 

 lication in regard to the chemical action 

 involved in the production of charcoal. 

 I have become much interested in the 

 subject since we began to use in the 

 office an air-tight, wood burning stove 

 for coal saving. I had not seen one of 

 these stoves since I was a boy, and it 

 brings back the memories of those 

 days and how I wondered even then at 

 the action of an air-tight stove. We 

 can put in heavy wood and a fierce fire 

 follows if the draft is left on. but if it 

 is closed entirely the wood is converted 

 into charcoal, and on opening the door 

 we sometimes find almost a peck of the 

 live coal which flames up as soon as air 

 is brought to bear upon it. 



I recall as a boy spending much time 

 with the woodchoppers and coalpit 

 burners. I remember that they made a 

 huge, semispherical pile of wood, cover- 

 ed it with earth and lit a fire in one end. 

 Gradually the fire worked through the 

 entire pile and converted it into char- 

 coal. I remembered being puzzled by 

 the expression, "We must look out that 

 it does not get on fire," when the fire 

 was even then working all through it. 

 Men stamped down the turf and kept it 

 tight as the pile settled. 



I recall that I was informed at one 

 time when I was in Pennsylvania that 

 a coal mine there had been on fire for 

 many years and apparently was burn- 

 ing without the admission of air. What 

 is the action in these cases? If the 

 mine burns and the charcoal is pro- 

 duced without air or with a very limit- 

 ed supply, what is the difference in the 

 combustion that produces ashes and 

 that that makes charcoal ? 

 Yours very truly, 



Edward F. Bigeeow. 



Wood Charcoal. 



FREDERICK II • GETMAN, PH.D., E. C. S., 

 STAMFORD, CONNECTICUT. 



Wood charcoal is made by burning 

 wood in pits or kilns with a limited 

 supply of air, or by heating wood in 

 closed retorts. 



The process of charcoal burning may 

 be illustrated by the following simple 

 experiment. Place a few small pieces 

 of wood in a crucible and cover with 

 sand to protect the wood from the air ; 

 heat the crucible until all combustible 

 gases cease to be evolved. On cool- 

 ing the crucible and removing the pro- 

 tecting layer of sand, the wood will be 

 found to have undergone complete 

 transformation into charcoal with con- 

 comitant shrinkage in volume. 



It is to be noted that charcoal is 

 here produced without access of air — 

 the layer of sand completely or almost 

 completely excluding any atmospheric 

 action. From this we see that char- 

 coal is produced from wood by the 

 action of heat without undergoing com- 

 bustion. 



The process involved in the produc- 

 tion of charcoal is known as "destruc- 

 tive distillation." In general, this term 

 refers to all cases of chemical decom- 

 position produced by the action of heat 

 in the absence of air. The substances 

 which are ordinarily subjected to des- 

 tructive distillation are of organic ori- 

 gin and hence the end-product con- 

 sists largely of carbon. For this reason 

 the process of destructive distillation 

 is often designated as "carbonization.'" 



When wood is heated in the air it 

 "takes fire" and burns to ash. When 

 charcoal is heated in the air it also ig- 

 nites and burns to ash, but charcoal is 

 not an intermediate product in the 

 combustion of wood. Charcoal is the 

 residue from the destructive distilla- 

 tion of wood and absolutely no air or 

 oxygen is essential to its production — 

 in fact the more air there is present 

 the smaller the yield of charcoal will be. 



