18 ABSTRACTS OF OHEMIOAL PAPERS, M i n e r a l o g i c a l Chemistry. Canfieldite, a new Germanium Mineral. By S. L. PENFIELD (Amer. J. Ssci., 46, 107--113).--This new mineral was brought from Bolivia by F. A. Canfield. It crystallises in combinations of the octahedron and rhombic dodecahedron. The fracture is conchoidnl, t h e hafdness 2.5, the sp. gr. 6.27, the colour black, the streak greyish- black, aqd the melting point very low. The mineral consists ofMIh'ERALOGlCAL CEIEMISTRY. 19 silver, germanium, and sulphur, and has the same quantitative com- position as argyrodite. S. Ge. Ag* Total. Analysis gave the following results :- i 7-10 6.57 76-33 100*00 Thus canfieldite and argyrodite have the same chemical composition, which is Ag,GeS6. A new analysis, made by the author, of ar,gyrodite from Freiberg gave S.Ge. 4 3 . Total. 16.83 6.69 76.48 100.00 The mineral Ag,GeSs is therefore dimorphous, canfieldite being isometric and argyrodite monoclinic. B. H. B. Natural Manganese Oxides : Polianite and Pyrolusite. By A. GORGEU (Bull. SOC. Chim., [3], 9, 496-502).--The author has examined a specimen of polianite from Platten, in Bohemia, and specimens of crystallised pyrolusite from many localities in Central and Eastern Europe. The hardness of the polianite was 6.5, and its sp. gr. 5.03 to 5-09; whilst the hardness of the pyrolusite varied from 2-51 to 5.0, and the sp. gr. from 4-75 to 5.10, according to the degree of hydration. Only the polianite was really anhydrous, and the proportion of water in the pyrolusite varied from 0.75 to 2.65 per cent., only about one-third being given off in a vacuum, and a further quantity at about 280".The temperature of decomposition of the pyrolusites is above 460°, and is identical with that of the artificial varieties. When incompletely dissolved by hydrochloric acid, the residue has the composition of manganese peroxide. Boiling nitric acid, concentrated or dilute, dissolves only a trace of manganese. The impurities in the pyrolusites are practically the same in all cases, namely, iron, calcium, magnesium, lead, barium, potassium, and sodium, and sulphuric, carbonic, phosphoric, and arsenic acids ; they are present only in small proportion. The percentage of man- ganous anhydride, Mn02, present after abstraction of the impurities varies from 98 to 100 per cent. C.H. B. Rowlmdite. By W. E. HIDDEN and w. F. HILLEBRAR'D (Amer. J. Sci., 46, 208-212).-About 2 lbs. of this mineral was found by W. E. Hidden, in a, shipment of yttria-bearing minerals from Llano Co., Texas. The mineral is isotropic ; its hardness is 6 ; its sp. gr. 4.513 at 15.5" ; its fracture glassy-conchoYda1 ; its lustre vitreous-resinous ; and its streak is greenish-grey. An analysis by W. F. Hillebrand gave the following results :- EGO2. Ce20,. La, group. Y group. FeO. MnO. MgO. F. 26.04 5.06 9-38 47.70 4.39 0.67 1.62 3.87 These are in accord with the empirical formula Si~R4"'R"F2014. B. H. B. 3-220 ABSTRACTS OF CHEMIOAL PAPERS. Zoisite from North Carolina. By W. E. HIDDEN (Amer. J. Sci., 46, 154).-'Very pure monazite at the Flat Rock mine, Mitchell Co., North Carolina, was found by the author t o be surrounded by a pink, ritreous zoisite associated with a black, glassy allanite.An analysis of the zoisite gave the following results :- Si02. Al,O,. Fe2O8. MnO. CtlO. H20. Total. 39.98 31.02 4-15 0.25 23.80 2-03 100.21 The sp. gr. is 3.352 at 27". Mackintoshite, a new Thorium and Uranium Mineral. By W. E. HIDDEN and W. F. HILLEBRAND (Amer. J. Sci., 46, 98-103). -With thorogummite and cyrtolite in Llano Go., Texas, a new mineral has been discovered. It is opaque and black, but not quite so dull in lustre as the associated cyrtolite. A strong lens is neces- sary fo distinguish the two. The hardness of the mineral is 5.5, and no trace of cleavage has been observed. The fracture is sub-con- cho5dal to hackly, and the sp. gr.is 5.438 at 21". Its form is tetragonal, and resembles zircon and thorite in habit and angle. Square prisms, sometimes 1 cm. thick, with a simple pyramid, are all the forms thus far observed. It also occurs massive, nodular, and filling veins in cyrtolite and fergusonite embedded in coarse pegmatite. It is infusible before the blowpipe, and is not entirely decomposed by any one acid. Analysis gave results in accord with the formula UTh3Si3H601e, the formula of thorogummite being UTh3Si3H12021. B. H. B. B. H. B. 0 Alnoite containing Melilite. By C. H. SMYTH (Amer. J. Xci., 46, 104--107).-The author described (Abstr., 1892, 1057) a small dyke occurring in a fault fissure at Manheim, New Pork. Recently some sectious have been prepared from fresher material, and these show that one of the constituents is melilite, a supposition that the authoy originally hesitated to accept.Upon the basis of its mineralogical composition, and from a comparison with a specimen from Alnii, the rock must be classed as alnoite. The optical properties of the melilite are fully described, the mineral, although consisting chiefly of positive material, having patches of a negative character scattered through them. B. H. B, Actinolite Magnetite Schists in Ninnesota. By W. S. BAYLEY (Amer. J. Sci., 46, 176--180).-Attention has repeatedly been called to the existence of beds of amphibole schists associated with the ores in the older iron ore regions of the Lake Superior distdrict. Consequently, their discovery on the newly opened Mesabi range is of interest from a theoretical standpoint. The descriptions of them given by the author agree very closely with those given by Irving andVan Hise (Abstr., 1892, 794) for the corresponding schists in the Penokee series, except that in the Minnesota rocks quartz is rare, and haematite is absent. The presence of these peculiar rocks in the Mesabi range is noteworthy, since their origin in other districts hasPHYSIOLOGICAL CHEMISTRY. 21 been thought to be closely connected m-ith that of the iron ores with which they are associated. B. H. B.