74 Fertilizers 



basic-slag. When apatite or other phosphates are fused 

 with lime and silica, a product is formed which is very 

 similar to basic-slag, known as artificial basic-slag meal. 



Wiborgh phosphate. By fusing feldspar, sodium car- 

 bonate and phosphorite at a very high temperature, a 

 product is obtained which contains from 20 to 30 per 

 cent of available phosphoric acid. It has been found to 

 compare very favorably with superphosphates and basic- 

 slag, especially when used upon muck and peat soils. 

 The cost of manufacture is too great to make this material 

 of practical importance. 



Walter phosphate. This material is manufactured by 

 fusing powdered phosphorite, sodium sulfate, calcium 

 carbonate, sand and coke. When the material is hot 

 it is run into water and finely pulverized after cooling. 

 It compares favorably with basic-slag. 



Palmaer phosphate. This is a high-grade phosphatic 

 material containing 35 to 40 per cent of phosphoric acid 

 in the reverted form, practically all of which is available. 

 It is of especial importance because it affords a means 

 of utilizing mineral apatite. In the process of manu- 

 facture apatite is treated with chloric or perchloric acid 

 generated by electricity from sodium salts. It is more 

 effective than basic-slag and compares favorably with 

 superphosphates. 



Phosphatic guanos. 



Guanos rich in phosphoric acid were for many years 

 previous to the development of the phosphate mines 

 used extensively in this country. The Peruvian guano 

 of earlier times was particularly rich in nitrogen; the 

 purely phosphatic guanos are rich in phosphoric acid, 

 and are excellent materials. Very little of this material 



