688 TECHNICAL CHEMISTRY 



future generations. Of this, as of every great industry it may be 

 said that the supply of raw material for to-morrow is a problem 

 for to-day. 



Dr. H. W. Wiley, of the United States Department of Agricul- 

 ture, has pointed out the surprisingly large amount of potash, phos- 

 phoric acid, and nitrogen which is yearly taken up by the agri- 

 cultural crops alone. The average percentage of ash in all of the 

 important crops has been accurately determined and their per- 

 centage composition in respect to potash and phosphoric acid is 

 known. In addition to this we have a satisfactory knowledge of 

 the percentage of albuminous matter contained in the more im- 

 portant agricultural products. From these figures and the reports 

 of the United States Department of Agriculture we can calculate 

 the amount of potash, phosphoric acid, and nitrogen consumed 

 each year. Allowing a value of 4 cents a pound for potash, 5 cents 

 for phosphoric acid, and 12 cents for nitrogen, the total value of 

 these ingredients for a single year amounts to the enormous sum 

 of $3,200,000,000. To be sure this is not all removed from the farm 

 and lost to the soil; but that which remains in the form of straw 

 and manure is but a small percentage of the whole. Straw is gener- 

 ally burned, while the soluble salts of the manure-heaps are often 

 allowed to leach out and go to waste. When in addition we con- 

 sider the terrible waste involved in the modern methods of sewage 

 disposals where, instead of being returned to the soil, these valu- 

 able constituents are carried to the ocean, the net loss of these 

 chemicals can be easily appreciated. 



Of these three most important ingredients making up a fertil- 

 izer for general purposes, phosphoric acid alone seems to be at hand 

 in practically inexhaustible quantities. Slag, rich in phosphoric 

 acid from certain metallurgical processes, is already much used as 

 a source of the material. Fresh deposits of phosphate rock of such 

 enormous extent are being brought to light almost every day that 

 our supply of this material may give us little immediate concern. 



Although the Strassfurt region of Germany may continue to 

 ship undiminished quantities of potash salts, the second import- 

 ant ingredient of a fertilizer, the world's supply cannot be said 

 to be on a perfectly satisfactory basis until independent sources 

 are developed. In the year 1902 the value of the potash salts 

 imported into the United States amounted to $4,500,000. The 

 recovery of potash from wood ashes, while once an important in- 

 dustry, must diminish as the value of hard wood increases. While 

 there are doubtless natural beds of potassium salt still to be dis- 

 covered, the time seems rapidly approaching when we should render 

 more readity available the great amount of potassium distributed 

 throughout the mineral kingdom.. Rhodin had already accom- 



