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IOWA DEPARTMENT OF AGRICULTURE. 



of the chemical composition of the wood and bark of the chestnut oak, red 

 oak, black oak, etc.. the western hemlock and other trees being in- 

 cluded also. 



The production of wood for fuel purposes is still another important 

 product of the forest. Coal is used to a larger extent for this purpose 

 than wood, yet wood has many advantages. It kindles quicker and is 

 cleaner. As coke is produced from coal, charcoal may be produced from 

 wood. To show the effect of heat on wood the following may be of interest; 



TEMPEEATUBE. 



CHARACTER OF PRODUCT. 



150°C.=302°F... 

 200°C.=392°F... 

 270° C. =518° F... 

 350°C.=662°F 

 440° C. =824° F... 

 945 °C. =1733 °F.. 

 1045° C. =1913° F 

 1775 °C. =3227 °F 



Imperfectly carbonized. 

 Brown charcoal. 



Black charcoal. 



Wood in a dry condition contains 50 per cent of carbon, 6 per cent of 

 hydrogen, 42 per cent of oxygen. 1 per cent of nitrogen and 1 per cent of 

 ash, and has a calorific value of about 3,000 calories while black charcoal 

 has a value of 8,000 calories. When we compare the composition and 

 calorific value of the products of the forest with the various varieties of 

 coals we realize the value of wood for fuel purposes, as may be seen by the 

 following results: 



While wood will furnish only about one third the heat that can be 

 obtained from anthracite coal, its cost in many localities is a favorable 

 consideration. Black charcoal, however, compares favorably pound for 

 pound as a heat producer. 



As the attention given to the application of science to the problems 

 connected with forestry increases, the greater will be the demand upon 

 dendro chemistry for aid in the work. The products of the forest used in 

 commerce will be subjected to adulteration more and more. Turpentine 

 will be found to contain substances which have been added to increase 

 the profit of the producer. The gums will consist largely, if not entirely 

 of cheaper substances and these will be represented as the natural prod- 

 ucts. Adulteration of the products of the forest will be possible in many 

 ways and to protect these products will be an important work or dendro 

 chemistry. 



The study of the physiological processes of the growth of the tree 

 will offer a splendid opportunity for research and the results will not only 

 add to our knowledge but will be of practical value. 



