330 ANNUAL OF SCIENTIFIC DISCOVERY. 



in the magnetite bed of Scandinavia, and the composition of the bog iron- 

 ore of the same locality, suggested the possibility that the former might have 

 originated from bog iron-ore under the influence of chlorid of sodium at 

 a high temperature. The bog iron-ore contains, besides oxyd of iron, 

 phosphoric acid, lime, silica, titanic acid, and carbonaceous organic substances. 

 The latter ingredient might correspond to the remarkable bituminous sub- 

 stance of the magnetite beds, and the silica, lime, and manganese might be 

 supposed to form, with oxyd of iron, the numerous compounds of the amphi- 

 bole series occurring in the magnetite beds, while apatite and titanium com- 

 pounds might also be derived from the constituents of bog-iron ore. 



For the purpose of ascertaining the behavior of bog-iron ore when melted 

 with chlorid of sodium, a direct experiment was made. The cooled mass 

 presented cavities which, when the chlorid of sodium was dissolved out, were 

 found to contain apatite crystals. The ore itself had become black, strongly 

 magnetic, and had acquired such a hardness as scarcely to be scratched by 

 steel, together with a perfectly conchoidal fracture. In the larger cavities 

 the mass was covered with small, sharply-defined crystals, which, when mag- 

 nified, were found to be regular octahedrons. The ore was, therefore, actually 

 converted into magnetite, and the phosphoric acid had separated as apatite 

 from the oxyd of iron. In a comparative experiment with bog-iron ore 

 alone it did not show any sign of fusion or crystallization ; the color, though 

 darkened, was still brown. 



There is a great amount of evidence for the opinion that the blue tinge of 

 some minerals, especially silicates and aluminates, is intimately connected 

 with the presence in them of phosphate of iron, and that vivianite is the hy- 

 drate of the compound, to which the colors of cyanite, sapphirine, spinel, and 

 correndum, as well as fluorite and apatite is owing. The author having as- 

 certained by analysis, the presence of phosphoric acid and iron in these min- 

 erals, endeavored to obtain further evidence by synthetical experiments, and, 

 first, to find whether the anhydrous phosphate of iron had the same color as 

 the hydrate. This was found, under certain conditions, to be the case, and 

 the whole course of experimentation showed that phosphate of iron is capa- 

 ble of producing, in combination with alumina especially, but likewise with 

 other substances, a series of colors, of which the intermediate phase is pure 

 blue ; on the one side the dark violet seen in some varieties of fluorite, and 

 on the other the bluish green of the apatite. In some instances these colors 

 may pass, by a subsequent oxydation, into yellow and red shades, like those 

 so frequently observed in cyanite. Edinburg Philosophical Journal. 



MINERALS OF THE GOLD REGIONS OF CALIFORNIA. 



Mr. William P. Blake, United States geologist, in a communication published 

 in Sillimaris Journal, makes the following observations on certain of the mine- 

 ral productions of California: 



Crystalline Gold. Good crystallizations of gold are comparatively rare in 

 California. At Forest Hill, Placer county, an imperfect octahedral crystal of 

 large size was found last year. The placers are only partially developed for 



