PEINCIPAL PHOSPHATE DEPOSITS. 



41 



about 30 per cent of phosphoric acid, and 6 per cent of oxide of 

 iron and akimina. 



5. Alta Vela Phosphate. — This phosphate has a composition 

 analogous to that of Redonda phosphate, as the following analysis 

 ■shows : — 



TABLE XXXI.— ANALYSIS OF ALTA VELA PHOSPHATE. 



Phosphoric acid . 



Oxide of iron 



A umina 



Lime .... 



Sasquioxide of c premium 



Per cent. 



37-00 



24-00 



15-00 



1-00 



0-7o 



6. Rata or Fernando Noronjo PhosjjJiate. — This phosphate occurs 

 as a fine powder ; it also is very rich in oxides of iron and alumina, 

 .and thus unfit for superphosphate manufacture. It contains about 

 26 per cent of phosphoric acid and up to 20 per cent of oxides of 

 iron and alumina. 



7. Monk's Island (Caribbean Sea) Phospho Guano. — This phos- 

 phate contains 42 per cent of phosphoric acid and only 40 per cent 

 of lime. It consists therefore partially of monacid phosphate. Its 

 analysis gave the following results : — 



TABLE XXXII.- 



. ANALYSIS OF MONK'S ISLAND PHOSPHATE. 



Per cent. 

 Nitrogenous organic matter and combined water 

 Sulphate of lime 



Phosphate of lime an I magnesia 

 Alkaline salts 

 Carbonate of lime 

 Carbonate of magnesia 

 Insoluble silicious residue 



7-60 



8-32 



70-00 



1-88 



10-20 

 2-00 



100-00 



The surface of this deposit, which is as hard as a rock, has not the 

 same composition as the centre. Thus the bed having been care- 

 fully analyzed yielded 70 per cent of phosphate of lime on the 

 surface, 74 per cent in the centre, and 75 per cent in the lower part. 

 8. Christinas Island Phospho Guano (Indian Ocean). — Christ- 

 mas Island, to the south of Java, belongs to the Straits Settlements. 

 The phosphate deposit discovered there a few years ago is wrought 

 by a British Company, The Christmas Island Phosphate Co. Ltd. 

 The total bulk, of this deposit is estimated at 250,000 tons, with 

 a percentage of 60 to 90 of phosphate of lime. The samples re- 

 ceived in Europe tested 85 per cent of phosphate of lime with 1'5 

 per cent of sesquioxides ; rendered soluble by sulphuric acid at 53° 

 B., yielded about 20 per cent of phosphoric, of which 05 per cent 

 was insoluble in water, and 4 per cent of free acid, which is 

 little. This phosphate is very hard, but easy to crush when it is 



