TECHNICAL CHEMISTRY. 437 



Dr. H. W. Wiley, of the IT. S. Department of Agriculture, has 

 pointed out the surprisingly large amount of potash, phosphoric acid 

 and nitrogen which is yearly taken up by the agricultural crops alone. 

 The average percentage of ash in all the important crops has been 

 accurately determined and their percentage 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 con- 

 tained in the more important agricultural products. From these 

 figures and the reports of the U. S. Department of Agriculture we 

 can calculate the amount of potash, phosphoric acid and nitrogen con- 

 sumed each year. Allowing a value of four cents a pound for potash, 

 five cents for phosphoric acid and twelve 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 generally 

 burned, while the soluble salts of the manure heaps are often allowed 

 to leach out and go to waste. When, in addition, we consider the 

 terrible waste involved in the modern methods of sewage disposal, 

 where, instead of being returned to the soil, these valuable 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 fertilizer 

 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 this 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 important in- 

 gredient of a fertilizer, the world's supply can not 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 four and a half million dollars. The recovery of 

 potash from wood ashes, while once an important industry, must 

 diminish as the value of hard wood increases. While there are doubt- 

 less natural beds of potassium salt still to be discovered, the time seems 

 rapidly approaching when we should render more readily available the 

 great amount of potassium distributed throughout the mineral king- 

 dom. Ehodin had already accomplished much towards this end when 

 he showed that feldspar could be made to yield the greater part of its 

 potash when it was heated with lime and common salt. Clark has 

 found that when the mineral leucite with its 21 per cent, potassium 



