472 RECORD OF SCIENCE FOR 1887 AND 1888. 



This miueral is of interest: because it shows that the same form belongs 

 alike to the tantalate and niobate of iron and manganese, although the 

 mineral ordinarily called tantalate does not conform to this very closely. 

 (Described by A. Arzruni in Verh. Euss. Min. Ges., St. Petersburg, 

 vol. XXIII, 181.) 



Martinite. — A pseudoraorphous mineral having the form of gypsum, 

 but consisting chiefly of calcium phosphate ; it is from the gnano of the 

 Island of Cura^oa. It appears in aggregates of minute rhombohedrons, 

 white or yellowish in color. The specific gravity is 2.894. An analysis 

 gave: 



P2O6 CaO H2O Organic lusol. 



47.67 46.78 4.52 0;75 0.20 = 99.92. 



For this the formula is 20a3(P04)2, 4 CaHP04+H.,0. (Described by 

 J. FI. Kloos in Samml. Mus. Leiden, ser. 2, vol. i; abstract in Jahrb. 

 Min., 1888, vol. i, 41 ref.) 



MazapiUte. — Stated on the basis of a preliminary examination to be 

 an arseuite of calcium and iron. Itoccnrs in deep red to black crystals, 

 having a hardness of 7, and a specific gravity of 3.507. It is from the 

 mining district of Mazapil, Zacatecas, Mexico. (G. A. Koenig in Pro- 

 ceed. Acad. Nal. Sci., Philadelphia, Jnly 3, 1888.) 



Melanocerite. — See Barkevikite. 



Metalonchidite. — A varity of marcasite from the St. Bernhard mine, 

 near Hausach, Badeii. It is peculiar in containing 2.7 per cent, of 

 arsenic, with some nickel and lead, and hence approaches Breithaupt's 

 lonchidite. (Described by F. Sandberger in Oesterreich. Zeitschr. Berg. 

 Hiitt., 1887, vol. xxxv.) 



Meiastihnite. — A form of antimony sulphide, like stibnite in composi- 

 tion, but of a bright red color, like the corresponding compound obtained 

 in the laboratory. It occurs sparingly as an amor]djous red deposit at 

 Steamboat Springs, California. (Described by G. F. Becker in Mono- 

 graph XIII, U. S. Geological Survey.) 



NordenHliolMne. — See Barkevikite. 



Paposite. — A hydrous iron sulphate from the Union mine near Pa- 

 posa, Atacama. It occurs in dark red crystalline masses, having a 

 fibrous radiated strncture. The formula obtained by Darapsky is 

 2re203, 3SO:.4-10Il2O, so that it approaches closely to fibroferrite. 

 (Bol. Soc. Min. Santiago, No. 92, October, 1887, in Jahrb. Min., 1889, 

 vol. I, 23 ref.) 



Pscuclohiotife. — An alteration product of the biotite from the crystal- 

 lized limestone of the Kaiserstuhl. The mean of two analyses gave: 



Si02 TiOj AI2O3 FejOs MnsOs MgO K.^O U-iO 



:?5.91 1.115 15.18 10.85 0.89 22.80 2.90 10.77 = 100.45. 



It is not to be regarded as a definite compound. (Described by A. 

 Knop in Zeitschr. f. Kryst., 1887, vol. xii, ()07.) 

 R.hodotiUte. — A mineral occurring with heliophyllite (see above) at the 



