SECTION 11. IMPROVEMENTS IN THE MANU- 

 FACTURE OF FERTILIZERS 



IN the superphosphate industry there has been a steady 

 improvement in the composition and physical properties 

 of these fertilizers during many years. Thirty to forty years 

 ago, fertilizers rarely contained more than about 25 % of 

 soluble phosphate, whereas modern samples contain from 

 30 to 35 %. This improvement has been obtained by better 

 selection of mineral phosphates, and more careful attention 

 to details during the process of manufacture. The increase 

 in the percentage of soluble phosphates has been accompanied 

 by a correspondingly great improvement in the physical 

 properties of the material, which is now usually sold in dry 

 condition. Although the industry was founded in England, 

 the lead has long been lost. Few modern British makers 

 possess the mechanical dens and electric transport of the 

 modern continental factories of Europe, although there is 

 a marked tendenc)^ even among the smaller factories, to 

 utilize some of these modern engineering helps. Not merely 

 is there great hope of increasing the quantities of phosphatic 

 fertilizers used in the British Isles, but the remainder of the 

 British Empire is likely to need much phosphatic manure in 

 future ; in Australia alone, large areas are known to be 

 urgently in need of phosphatic manures. 



When phosphatic fertilizers were first introduced, the 

 results of the application of soluble forms produced such 

 striking results that the beneficial effects of insoluble forms 

 passed unnoticed. With careful experimental investigation, 

 the benefits resulting from the employment of the more 

 insoluble types became evident, and it is now probable that 

 mixtures of soluble and insoluble phosphates will become 

 popular. While the best farm land is steadily increasing in 



