THIRD ANNUAL YEAR BOOK — PART X. 613 



The value of the ash from wood may be calculated by taking the com- 

 mercial values of the potash of 5 cents per pound and of phosphorio acid 

 of 4 cents per pound. The nitrogen, the element of plant food which has 

 the greatest value, does not form part of the ash but escapes as a gas when 

 the wood is used for fuel purposes. 



PRODUCTS OF THE FOREST. 



Some interesting chemical processees are those known as destructive 

 distillation, paper making, the manufacture of varnishes, etc. The old 

 time process of charcoal burning where great masses of wood were covered 

 with earth and allowed to slowly burn to charcoal, has given place to the 

 more modern method of destructive distillation. The object in this process 

 is not only to produce charcoal but to save the volatile products and 

 separate them so that these substances are made to yield a revenue to 

 the manufacturers. The products produced from wood are charcoal, tar, 

 crude acetic acid, wood alcohol and gas. 



Wood tar is used in many cases as a preservative for wood, especially 

 that known as Stockholm tar. Wood tar creosote is prepared from wood 

 tar and is used in place of coal tar creosote for preserving railroad 

 ties. The purified product is used in medicine as an antiseptic. 



Wood alcohol is also a product from the distillation of wood and is 

 used in varnishes, the preparation of aniline colors and as a cheap sub- 

 stitute for common alcohol in lamps. Another product is acetone which 

 is used quite extensively in commerce. Acetic acid and the acetates 

 are also produced from the wood when it is subjected to distillation. 



In the production of the best varities of paper it is necessary to use 

 the best grades of cellulose fibres such as come from cotton and linen 

 rags, but for the largest production of the common variety of paper, the 

 wood of the forest furnishes the material. The daily newspaper could not 

 exist if it were not for the paper produced from the pulp of wood. 



The production of turpentine and the varnishes is another great in- 

 dustry which may be included under dendro chemistry. The vast pine 

 forest of the south and west are sending out great quantities of turpen- 

 tin and rosin, to other parts of the country and it is only a question of time 

 before they are exhausted. Already chemistry has been used in the prepa- 

 ration of various products from the distillation of the roots of trees which 

 have been used for lumber. 



It was claimed that a tree from which turpentine and rosin had been 

 obtained was of less value for use as lumber and that its composition 

 was different from that of the normal tree. Chemistry and engineering 

 tests have shown that this is not true but that the chemical composition 

 of materials from both sources that of the normal tree and when the tree 

 has been tapped for turpentine and rosin, are the same and this is also 

 true for the material in its strength for general use. 



Another important work for dendro chemistry is that related to the 

 bark of trees used for tanning purposes. Already a department for this 

 work has been established in connection with the bureaus of forestry and 

 chemistry at Washington, and the first work undertaken relates to the study 



