416 On the Chemical Composition of Phosphatic Minerals 
In further illustration of the variable character of German 
phosphate, I quote the following analyses of cargo-samples : — 
General Composition of Various Samples of Nassau, or Lahx 
Phosphates. 
No. 1. i No. 2. 
No. 3. 1 No. 4. 
HI K 
No. 5. 
No. 6. 
Moisture and water of com-'l 
'^T^ll ncT^li nplfl 
Alumina, fluorine, carbonic'! 
acid, &c / 
Incoluble siliceous matter . . 
* Equal to tribasic phos-'l 
pljate of lime .. ../ 
2- 32 
33-49 
45-52 
3- 97 
9-49 
5-21 
2-40 
32-05 
44-44 
|l3-94 
7-17 
2-42 
31-08 
42-53 
15-77 
8-20 
2-54 
30-52 
42-20 
16-16| 
8-58 
1-39 
26-67 
38-27 
3-41 
8-65 
21-61 
3-86 
26-02 
37 62 
5-06 
10-32 
17 12 
100-00 
100-00 
100-00 
100-00 
100-00 
100 -od 
73-11 
69-96 
67-85 
66-63 
58-22 
56-80 
It may be stated that impure varieties are much more abun- 
dant in the Lahn valley than those richer in phosphoric acid. 
Although the quality may be considerably raised by the plan 
adopted in the German phosphate mines, of sifting and washing 
the impurer sorts, a large proportion of the mine-produce is too 
poor in phosphate of lime to repay the cost of exportation to 
England, for unless a cargo contains about 65 per cent, of phos- 
phate of lime, German phosphate cannot be profitably sent into 
this country. 
8. French Phosphate. 
The discovery of mineral phosphates in the valley of the 
Lahn, in Nassau, has lately been eclipsed by that of extensive 
and valuable phosphatic deposits in the valley of the Lot, a 
tributary of the riyer Garonne, which flows through the upper 
and middle beds ofthe Jura and the lias formations. During: the 
last few years large quantities of phosphate have been imported 
into England from the South of France. This phosphate is 
known in England under the name of French, or Bordeaux 
phosphate, it being usually shipj)cd from that port. Like Lahn 
phosphate, the French deposit occurs in pockets, and varies 
greatly in aj)pearance, texture, and in its chemical composition 
and commercial value. 
Occasionally I'rencli phosphate is found in snow-white coin- 
pact masses of a moderate degree of hardness, and breaking 
