used for Agricultural Purposes. 
411 
and quartz. It always contains more or less, and not infrequently 
a good deal of, quartz, and as a rule either no carbonate of lime 
or only a small percentage. 
Spanish and Portuguese phosphorites belong to the class of 
fluoride apatites. The proportion of fluoride of calcium, how- 
ever, varies much in the produce from different mines, but all 
contain considerable proportions, occasionally amounting to 12 
and even 14 per cent. 
The following analyses show the composition, as ascertained 
by me, of very rich specimens of phosphorite from Caceres and 
Montanchez : — 
. Composition of Spanish Phosphoeite. 
Cacebes. 
Montanchez. 
No. 1. 
No. 2. 
No. 3. 
No. 4. 
Fluorine, carbonic aciil, and a little oxide j 
Insoluble siliceous matter (quartz rock) 
* Equal to tribasic phosphate of lime .. 
•21 
38^85 
51-65 
2-61 
6-68 
•24 
34-89 
46 55 
2-91 
15-41 
•16 
39 -OJ 
51-77 
3-02 
5-96 
-18 
39-46 
52-66 
4-95 
2-75 
100-00 
100-00 
100-00 
100-00 
84-33 
76-17 
85-33 
86-14 
Practically speaking, these samples were free from oxide of 
iron and alumina, and they contained only an insignificant 
proportion of carbonate of lime, and all four were rich in phos- 
phate of lime. The highest percentage of phosphate of lime 
which I ever found in a Spanish phosphorite was 88-98, that is 
in round numbers, 89 per cent. 
Whole cargoes imported into England rarely, if ever, turn 
out so rich in phosphate of lime as the preceding samples. 
The finest cargoes seldom yield more than from 70 to 72 per 
cent., and the majority from 60 to 65 per cent, of phosphate of 
lime. 
In illustration of the range of quality of recent shipments 
I quote the following analyses (p. 412) of samples repre- 
senting whole cargoes imported into England since January 
of the current year. Some of these samples contained a good 
deal of carbonate of lime, a constituent which as a rule 
does not enter largely into the composition of Spanish phos- 
phorite. 
1 2 E 2 
