43 



potash, from which it can only be freed by recrystallization in from 

 10 to 15 per cent hydrochloric acid. The mother liquors, from which 

 nearly all of the oxalic acid has been separated, contain the excess of 

 sulphuric acid used in setting oxalic acid free and some oxalic acid, 

 and are used, after being brought to the desired strength by the 

 addition of concentrated acid, for the decomposition of the next lot 

 of oxalate of lime. 



Light woods, such as pine, fir, and poplar, give the best yields, 

 amounting to about 90 per cent of the weight of the dry wood, while 

 the heavy woods oak, beech, etc. yield about 80 per cent. 



Oxalic acid is largely used as a discharge in calico printing and 

 dyeing, for bleaching flax and straw, for bleaching leather, and in 

 the manufacture of formic acid. 



SUGGESTIONS FOB THE DEVELOPMENT OF THESE INDUSTRIES. 



The industrial processes briefly described in the preceding pages 

 separate or prepare from wood certain chemical compounds, some of 

 which are important articles of commerce, their total value per unit 

 of wood being greater than that of the wood from which they are 

 obtained. Thus, taking average yields of well-operated plants and 

 valuing the products at current wholesale prices, a cord of wood may 

 be said to yield the following approximate gross values : 



Hard wood, destructively distilled $11. 00 



Pine (good light wood) 25. 00 



Pine (good, steam-distilled) 7. 00 



Pine extracted with soda, soda pulp made 44. 00 



Pine extracted with volatile solvents and pulp made from residue 46. 00 



Pine extracted with volatile solvents and residue destructively distilled 26. 00 



No figures are given for oxalic acid, for the reason that the industry 

 is undeveloped in this country, and while the gross values are much 

 greater than those given in the preceding statement for other chemical 

 products the cost of production is relatively much higher, and a 

 theoretical statement in regard to its production might be misleading. 



It must be fully understood that these values are given merely for 

 purposes of illustration and are only approximate gross values, as the 

 yield at any one plant may vary widely above or below those given. 

 They are based on the yields from well-equipped and carefully operated 

 plants using good grades of wood. The several products are priced 

 as follows: Charcoal, 4 cents per bushel; 80 per cent alcohol, 30 cents 

 per gallon; turpentine, 60 cents per gallon; rosin, $4 per barrel; tar, 

 $6 per barrel; gray acetate, $2.50 per 100 pounds; unbleached soda 

 pulp, 2 cents per pound. 



From the gross values certain fixed charges must be deducted. 

 They are cost of raw material at the plant ; cost of operating (labor, 



[Cir. 36] 



