430 On the Chemical Composition of Phosphatic Minerals 
The sample, No. 1, contained only 52 per cent, of phosphate of 
lime in round numbers, and was so much mixed up with coral rock 
(carbonate of lime) that it was unsaleable ; whereas No. 2 con- 
tains a high percentage of phosphate of lime, but little oxide of 
iron and alumina, and not too much carbonate of lime to prevent 
its being classed with high grade mineral phosphates. 
14. Akuba Island Phosphates. 
Another phosphatic rock or mineral has recently been dis- 
covered on Aruba Island, one of the Leeward Islands in the 
Caribbean Sea, situated 12° 36' north latitude, and 70^ 8' west 
longitude. 
In 1824 gold was found on Aruba, a Dutch possession, and is at 
the present time explored by the Aruba Gold Mining Company,, 
who have also recently obtained a concession from the Dutch 
Government to work and export the newly discovered phosphatic 
mineral deposits on that island. 
The samples of Aruba rock phosphate which have come under 
my notice are compact hard stone-like masses of a light-brown 
or yellowish colour, with darker chocolate-brown coloured bands 
and blotches, which give the Aruba phosphate a peculiar and 
characteristic appearance. Veins of calc-spar not infrequently 
interlace the phosphatic mineral, which probably will be found 
even a more valuable acquisition than the gold-mines. Aruba 
phosphate, I find, contains from 63 to 76 per cent, of phos- 
phate of lime, with variable quantities of carbonate of lime, 
oxide of iron, alumina, insoluble siliceous matter, and similar 
impurities usually found in phosphatic minerals. In illustration 
of the chemical character of Aruba phosphate, I subjoin analyses- 
of several samples Avhich have recently been submitted to me for 
examination : — 
CoMrosiTioN OF Five Samples of Aruba Phosphate. 
No. 1. 
No. 2. 
No. 3. 
No. 
No. 6. 
Moisture and ■water of combi-'l 
♦Phosphoric acid 
tCar))onic acid 
Insoluble sUiceous matter 
* Equal to tribasic phosphate 
t E'luiil to carbonate of lime 
5- 55 
31-11 
41-69 
6- G9 
1 14-72 
•24 
100 00 
3-79 
33-04 
47-53 
1 14-6o| 
104 
100-00 
5-54 
28^95 
30^18 
•fl8 
9-26 
17-22 
7^87 
100-00 
3-79 
33-04 
47-53 
j 14-60 
1-04 
100-00 
5-48 
34-94 
42-91 
16-43 
•24 
100^00 
67-91 
15-20 
72- 13 
03-20 
2-23 
72-13 
76 --'8 
