356 Chemical Composition and Commercial Value of 
of sheet-iron, it becomes beautifully phosphorescent — hence its 
name. 
In Estramadura this phosphorite has been employed as a 
build iug'-stone. Professor Hausmann, of Gottingen, in his classical 
Handbook of Mineralogy, published in 1847, says with respect 
to the Spanish phosphorite, that building purposes are probably 
the only use to which this mineral can be applied. 
We in England of course know how to turn ])hosphorite to a 
better purpose than that of building houses with it. The fact, 
however, that such a valuable mineral is, or, more correctly 
speaking, has been, used for building purposes not many years 
ago, shows plainly in what immense layers it is to be found at 
Lagrosa. It is to be regretted that the want of adequate means 
of transport and other difficulties have hitherto prevented this 
valuable deposit from being brought in large quantities to the 
English market. 
Several large cargoes of Estramadura phosphate," it is true, 
found their way hither two years ago, but the importers lost 
money by the speculation, although the mineral was sold at a 
rate quite high enough in comparison with the then current price 
of bone-ash and other phosphates. 
The following analyses were made from average samples, 
fairly representing the composition of the different cargoes : — 
Composition of Spanish (^Estramadura) Pliosphorite. 
No. 1. No. 2. 
Moisture and water of combination '68 1"42 
Lime 42-^8 41-47 
*Phosplioric acid 3G'3(> o3'55 
Oxido of iron, alumina, magnesia, and ( determined \ g.^-j^ ^.j^g 
fluorine I by difference / 
Insoluble siliceous matter 11'47 18"37 
100-00 100-00 
* Equal to tribasic phosphate of lime (bone-earth) .. 78-79 72-69 
It will be seen that the Spanish phosphorite is not equal to 
the best samples of Norwegian apatite. It is, however, a valuable 
mineral, since it is rich in phosphate and free from carbonate 
of lime. 
Like Norwegian apatite, the Estramadura phosphorite must 
be reduced by means of powerful machinery to a fine powder, 
and afterwards treated with sulphuric acid, before it can be 
economically employed for manuring purposes. 
Fibrous phosphorite has also been found at Amberg, in 
Bavaria. This phosphorite resembles, in composition and struc- 
ture, that of Estramadura, but is distinguished from it by con- 
taining some iodine. 
Bavarian phosphorite has lately been raised in some quantities, 
