used for Agricultural Purposes, 
427 
to a fine powder. It contains but little oxide of iron and alumina, 
but rather more carbonate of lime than in foriner years, which 
appears to indicate that at present the phosphate is mined in 
close proximity with the coral rock on which it rests. 
11. Navassa Phosphate. 
The small uninhabited island of Navassa is another island in the 
Caribbean Sea which supplies a phosphatic rock. It is situated 
in 18° 25' north latitude, and 75° 5' longitude west of Greenwich ; 
33 miles south-west of Hayti, and 72 miles east of Jamaica. 
It appears to be a coral island raised from the sea ; and, like 
the island of Sombrero, it is surrounded by coral reefs, which 
greatly impede the shipment of the rock. 
The coral rock which forms the framework of the island is 
full of cavities, and these are filled with phosphatic mineral 
deposits of a reddish-brown colour. 
The bulk of the deposit consists of globular grains of phos- 
phate of lime, cemented together into hard masses and contami- 
nated with a good deal of oxide of iron and alumina, some 
carbonate of lime, and siliceous matter. 
Navassa phosphate, like most minerals of a similar character, 
varies in composition, as will be seen by the following detailed 
analyses of three samples, made in my laboratory: — 
Detailed CoiMPOsiTioN of Navassa Phosphate. 
»o. 1. 
No. 2. 
No. 3. 
Water of combination and organic matter 
.5-91 
5-46 
31-18 
37-70 
2-38 
4-18 
911 
1- lG 
2- 92 
8- 50 
415 
28-47 
34-07 
•45 
2-30 
4-49 
9- 48 
1-81 
U-28 
1 12-08 
31-15 
38-58 
2- 29 
3- 98 
1 9-30 
2-02 
Sulphuric acid, fluorine, &c 
* Equal to tribasic phosphate of lime 
100-00 
100-00 
100-00 
G8-07 
5-41 
G2-15 
5-22 
68-01 
5-20 
The total amount of lime in Navassa phosphate is insufficient 
to form, with the carbonic and phosphoric acid, carbonate and 
tribasic phosphate of lime, and consequently a portion of the 
phosphoric acid must be united either with oxide of iion or with 
2 F 2 
