viii CONTENTS. 



PAGES 



j)liosphate — 2. Sombrero phosphate — 3. Navassa phosphate — 4. 

 Aruba phosphate — 5. Alta Vela phosphate — 6. Rata or Fernando 

 Noronjo phosphate — 7. Monk's Island (Caribbean Sea) phospho 

 guano — 8. Christmas Island phospho guano. (II.) Pacific Ocean 

 Isles: — Baker Island guano — Jarvis guano — Fanning Island guano 

 — Brown Island guano — Mejillones guano — Lacepede Island guano — 

 Clipperton Island guano — Angaur Island phosphate — Makatea Isle 

 phosphatic deposits — Distribution of phosphates in the different 

 geological formations. (I.) Gneiss Epoch. (II.) Paleozoic (or primary) 

 epoch — 1. Silurian formation — 2. Devonian formation — 3. Carbon- 

 iferous formation. (HI.) Mesozoic or secondary epoch — 1. Trias for- 

 mation — 2. .Jurassic formation — 3. Cretaceous — Cainozoic or Ter- 

 tiary epoch — Eocene formation — Quaternary and recent epoch - 14-49 



Geographical distribution of phosphate of lime and guano deposits and 



their chemical composition — Table ------- 50-59 



CHAPTEE III. 



DRYING AND ENRICHMENT OF PHOSPHATES. 



Drying — Calcining the nodules — Two tests — Different methods of 

 strengthening and utilizing poor quality phosphates : — 1. Dumonceau 

 and Nicolas — 2. Simpson — 3. Brochon — 4. Winsinger — 5. O. lahne 

 — 6. Martin — 7. Thonnar and Huxton — 8. Schucht — 9. Carr — 10. 

 Glaser — 11. Petermann — 12. Hodgkins — Manufacture of precipitated 

 phosphate by electrolysis - . _ . 60-66 



CHAPTEE IV. 



HISTORICAL REVIEW OF SUPERPHOSPHATE MANUFACTURE. 



The manufacture of superphosphates from 1850 to 1870—1871 to 1880— 



1880 to 1894—1895 to 1908 - 67-72 



CHAPTEE V. - 



THEORY OF MANUFACTURE OF SOLUBLE PHOSPHATES. 



Effect of the impurities in phosphates on their behaviour in the process 

 by which they are rendered soluble— Carbonates of lime and magnesia 

 — Iodine — Calcium fluoride — Organic matter — Method of determin- 

 ing the amount of acid to use in order to render the phosphate 

 soluble 73-83 



CHAPTEE VI. 



MANUFACTURE OF SUPERPHOSPHATE. 



1. The grinding of the raw phosphate — 2. Dissolving the ground phos- 

 phate in sulphuric acid — 3. Drying the superphosphate — 1. Grind- 



