On Phosphatic Guanos. 
451 
which is made simply by dissolving such crust phosphates than 
is the case when ordinary phosphatic minerals are used. 
The following is an analysis of a sample of Raza Island 
crust guano, which is very similar in chemical character to the 
sample marked No. 2 in the preceding tabular statement. 
Composition of Baza Island Guano. 
Moisture and organic mattev 12 '34 
*Phosphoric acid 38 'So 
Lime 36 '57 
Magnesia, alkaline salts, snliihuric acid, &c. ,. 8 '71 
Insoluble siliceous matter 4 • 03 
100-00 
* Equal to triba>ic phospbate of lime .. .. 83 "72 
A considerable proportion of this crust guano consisted of 
bibasic phosphate of lime. 
Curagao Island Guano. — The island of Curacao, a Dutch 
possession, is situated in 12° N. latitude and 51° w. longitude, 
a few miles off the coast of Venezuela. It is a small island, 
sparsely inhabited, and abounds in sterile rocky districts in 
which phosphatic guano deposits were discovered not many 
years ago. Cura(jao guano has a light greyish-brown colour, 
and like most deposits of that kind is free from smell. It is 
generally found in the shape of a fine voluminous powder, and 
is much liked by manufacturers of artificial manures, because 
when treated with sulphuric acid it is readily converted into a 
light, dry, and concentrated superphosphate. 
Composition of CuRArAo Guano. 
No. 1. 
No. 2. 
No. 3. 
No. 4. 
No. 5. 
No. 6. 
*Phosphoric acid 
Magnesia, sulpburicaeid,al-'l 
kaline salts, &c / 
Insoluble siliceous matter . . 
11-53 
7-11 
32-65 
40 19 
2-30 
6-02 
-20 
8-05 
8-70 
30-96 
42-05 
3-79 
6-21 
-24 
16-80 
6-30 
30-02 
37-40 
1-19 
8-05 
•24 
8-28 
7-34 
33-20 
41-86 
2-93 
6-20 
-19 
11-49 
5- 81 
33-44 
40-80 
1-86 
6- 31 
-29 
10-29 
7- 39 
29-55 
40-20 
3-74 
8- 74 
•09 
100-00 
100-00 
100-00 
100- 00 
100-00 
100 
00 
* Equal to tribasic phosO 
pbate of lime . . . . / 
t Equal to carbonate of lime 
71-27 
67-59 
65-23 
72-48 
73-01 
64 
51 
5-22 
8-61 
2-70 
C-C6 
4-27 
8 
50 
