PRESENT PROBLEMS 693 



plished in this direction. A number of uses have from time to time 

 been proposed for this waste, but as yet none have been of practical 

 value. Among the more promising may be mentioned a preparation 

 to be used in tanning leather, a sizing material for paper, and a sub- 

 stitute for dextrine in calico printing, and as an adhesive. 



In addition to our annual supply of 4,000,000 tons of paper stock, 

 we depend upon the forests for our supply of acetic acid, methyl 

 alcohol, and acetone. In countries where there is not the exorbitant 

 tax upon fermented mash that exists in the United States, there 

 would seem to be an opening for a process for the production of acetic 

 acid from alcohol in a more concentrated form than can be produced 

 through the aid of mycoderma aceti. It would, it is true, in the end 

 depend upon the supply of fermentative material; but there are 

 being wasted every year in the semi-tropical countries many thou- 

 sand tons of crude molasses that could thus serve an economic end. 

 For many uses acetic acid may be displaced by formic acid, a com- 

 pound which admits of synthesis from carbon and water. The farther 

 this substitution is carried the more acetic acid will be available for 

 the manufacture of acetone and other compounds where the acetyl 

 group is a necessity. 



Concurrent with the disappearing forests is the increasing scarcity 

 of vegetable tanning material. Hemlock and oak bark, sumac and 

 chestnut wood are still the most important sources of tannins, 

 although quebracho from South America and canaigre from Mexico 

 and Texas are daily playing a more important part. The introduction 

 of chrome tannage for upper leathers had a marked influence upon 

 this industry, inasmuch as it furnished a cheap substitute for those 

 finer tanning materials which are constantly increasing in price. A 

 mineral tannage for heavy hides, along the lines so successfully fol- 

 lowed for upper leather, has, however, not been developed; the pro- 

 duct lacks the rigidity and firmness combined with the flexibility 

 which is characteristic of oak or hemlock tanned leather. There must 

 exist methods for supplying to the hide materials having an action 

 analogous to these vegetable tannins; it remains but to seek them 

 out in order that a new and profitable industry may be established. 



It is thus seen that technical chemistry can do much for the con- 

 servation of our forests; along many lines the time for action has 

 already come. 



When the consumption of a given article is in excess of its supply, 

 the market price must rise. In accordance with this law we have seen 

 the price of crude India rubber more than double in the last few years. 

 The consumer of the finished article must pay this advance or accept 

 an inferior grade of goods. Generally he does both. 



The tropical forests of Africa and South America still contain 

 untold quantities of India rubber; but so does sea-water contain gold. 



