used for Agricultural Purposes. 
409 
72 per cent, of phosphate of lime, and cargoes are rarely shipped 
from Canada which contain less than 65 per cent, of phosphate 
of lime. 
The following analyses will convey a good idea of the 
high quality which characterises most samples of Canadian 
phosphate : — 
Composition of Canadian Phosphates. 
No. 1. 
No 
. 2. 
No. 3. 
No 
4. 
No 
. 5. 
No. 6. 
Moisture, water of combina-'> 
tion, and loss on ignition / 
•62 
10 
•11 
1 
09 
89 
1-83 
33-51 
41 
54 
37-68 
30 
84 
32 
53 
31-77 
46- 14 
54 
74 
51 04 
42 
72 
44 
26 
43-62 
Oxide of iron, alumina, 1 
7-83 
3 
03 
6-88 
13- 
32 
12 
15 
9-28 
Insoluble siliceous matter .. 
11-90 
59 
4-29 
12- 
03 
10 
17 
13-50 
100-00 
100 
00 
100-00 
100 
00 
100 
00 
100 00 
* Equal to tribasic phos-1 
pbate of lime .. .. J 
73.15 
90 
68 
82.25 
67. 
32 
71 
01 
69-35 
The sample No. 2, it will be seen, contained little more than 
5 per cent, of insoluble siliceous matter, and was extremely rich 
in phosphate of lime. As a rule, Canadian phosphate contains 
no carbonate of lime, and but little oxide of iron and alumina ; 
but it always contains variable and generally considerable quan- 
tities of fluorine. On dissolving Canadian apatite in sulphuric 
acid, irritating fumes of hydrofluoric acid are given off in large 
quantities ; and as these fumes are poisonous, care should be 
taken to effect the treatment of the powdered mineral with acid 
in closed vessels provided with ventilating shafts for carrying 
off the obnoxious vapours. 
Canadian phosphate is rather hard, and difficult to reduce to 
a fine powder, but it is otherwise well adapted for the manu- 
facture of concentrated superphosphate. 
The expense of freight from Canada to England in a great 
measure checks the development of the trade in Canadian phos- 
phate, and in consequence not many cargoes find their way into 
England in the course of the year. 
G. SpAJjisH A^D Portuguese PnosrHOKiTE. 
Extensive and valuable deposits of phosphorite are found near 
Logrosan, in the neighbourhood of the tlie towns of Caceres, 
VOL. XI. — S. S. 2 E 
