78 PHYSIOGRAPHY. CLASS II. 



edges and solid angles are rounded off, but it does not melt 

 without addition. With salt of phosphorus it forms a clear 

 globule. A phosphate of lime has been artificial!} 7 obtained 

 in lamellar masses of a greyish colour, by the younger 

 SAUSSURE, upon exposing a mixture of phosphoric acid 

 and sulphate of lime to a high temperature. These lamel- 

 lar masses shewed by heat opposite kinds of electricity on 

 opposite ends, a property which HAUY in vain tried to dis- 

 cover in the natural crystals of rhomb ohedral Fluor-haloide. 



4. There are examples, though few, of this species en- 

 tering as an occasional admixture into the composition of 

 rocks. Thus the granite of the neighbourhood of Rio Ja- 

 neiro, and the green prismatic Talc-mica, called common 

 Talc of Salzburg, contain varieties of it. More frequently 

 it appears in beds and veins consisting chiefly of ores 

 of iron and tin, particularly in the latter, associated 

 with pyramidal Tin-ore, prismatic Scheelium-ore, prismatic 

 Topaz, several species of Pyrites and Haloides, &c. In 

 another kind of veins, consisting of crystallised varieties of 

 those species of which the rocks themselves are composed, 

 it is accompanied by rhombohedral Quartz, and several 

 species of the genera Feld-spar and Talc-mica. The crys- 

 tallised varieties from Spain, called Asparagus-stone, occur 

 along with rhombohedral Iron-ore and compact rhombohe- 

 dral Lime-haloide ; the compound varieties, or Phosphorite, 

 of the same country, form particular beds. 



5. Ehrenfi iedersdorf in Saxony, Schlackenwald in Bo- 

 hemia, the Greiner mountain in Salzburg, Cabo de Gata 

 in Spain, Arendal in Norway, Devonshire and Cornwall in 

 England, afford some of the most generally known locali- 

 ties of fine varieties of rhombohedral Fluor-haloide. Very 

 beautiful crystals of this substance have lately been disco- 

 vered at Carrock in Cumberland, associated with the dif- 

 ferent species, which usually occur in veins and beds of 

 Tin-ore. From St Gothard in Switzerland, and Hei- 

 ligenbluter Tauern in Salzburg, remarkable white, transpa- 

 rent crystals have been brought. Other varieties occur in 



