MlN ERALOGICAL CHEMISTRY. ii. 55 Miner a l o g i c a1 C h emi stry. Determination of the Density of Minerals by means of Rohrbach's Solution of Standard Refractive Index. H. E. MERWIN (Amer. J. Sci. 1911 [iv] 32 425-428).-The density of rriineral grains may be determined by measuring the refractive index of a heavy liquid in which they remain suspended. The liquid with the suspended grains is contained in the small glass cell of a refracto- meter. A table is given showing the variation of the refractive index with the density for Rohrbach's solution (barium-mercuric iodide) at 20° ranging from D 3.449 and 12 1.7686 to D 2-067 and 1.1 1.5148. L. J. 8. Quartz and Fluorite as Standards of Density and Refractive Index. H. E. MERWIN (Amer. J. Sci. 1911 [iv] 32 429-432).-The use of these minerals as standards for checking the accuracy and adjustment of instruments is recommended since for material from different localities the constants named vary but slightly.Clear colourless quartz in twelve specimens from various localities was found to have DiO 2.6495 L- 0.0010 and (in five specimens) oD 1.54425 ? 0.00005. Clear pale-coloured fluorite from different localities has D;" 3.180 k 0.001 and nD 1.4338 + <0-0001. L. J. S. Lignite. 11. Volatile Constituents. GEORGE B. FRANKFORTER and ANDREW P. PETERSON (J. Amer. Chem. Soc. 191 1,33,1954-1963). -Analyses have been made of samples of lignite from North Dakota Canada and Alaska. It has been shown by Frankforter (J. Amer Chem. Soc. 1907 29 148s) that the lignites vary widely in the amount of moisture they contain samples from the Southii.56 ABSTRACTS OF CHEMICAL PAPERS. containing more than those from more northern districts. It has been found that the total amount of volatile constituents is greater in the latter. The composition of the volatile constituents varies t o some extent but not in any regular order. The amount of carbon monoxide is nearly constant and that of methane shows but little variation. The quantity of hydrogen however is greater the further north the locality from which the lignite is obtained. E. G. Some Minerals from Beaver County Utah. B. S. BUTLER and WALDEMAR T. SCRALLER (Amer. J. Xci. 1911 [iv] 32 418-424). -In the Horn Silver mine near Frisco the sulphide ores of lead zinc copper silver and iron give place in the upper levels to a large variety of secondary minerals consisting of oxides sulphates carbonates chlorides and silicates of the same metals.Beauerite described as a new species is one of these secondary minerals being a hydrous sulphate of copper lead and ferric iron. It occurs in some quantity as canary-yellow earthy and friable masses intermixed with other secondary lead and copper minerals. Under the microscope i t is seen to be minutely crystallised in bexagonal plates. Anal. I agrees with the formula CuO,PbO,( Fe A1),0,,2S0,,4H20. None of the water is expelled below 250' Fe,O,. Al,O,. PbO. CuO. ZnO. (E,Na),O. SO,. H,O. Insol. Total. II. 42'11 - 18-32 - 0.30 0.13 27-59 9.16 2'64 100.25 Plumbojarosite (Abstr. 1910 ii 966) occurs abundantly together with jarosite and alunite in the same mine and it has also been observed in several other mines iu Beaver Co.It forms dark brown micaceous masses and under the microscope shows golden-yellow hexagonal plates which are optically uniaxial and negative ; D 3.60. Anal. I1 agrees with the usual formula Pb0,3Fe,0,,4SO3,6H2O. The associated jarosite and plumboj arosite can only be distinguished by chemical tests. The rare mineral corkite a hydrous phosphate and sulphate of lead and ferric iron [differing from beudantite in containing phosphate in place of arsenate'] was found in two mines as a light yellowish-green earthy and friable material which under the microscope shows minute crystals. It is readily soluble in hot hydrochloric acid and contains a trace of copper but no arsenic.Wurtzite (hexagonal zinc sulphide) occurs in considerable abundance in the Horn Silver mine and when struck with a pick it phosphoresces ; crystals are described. Thortveitite a New Mineral. I. 17'28 3.64 29.44 9.70 - - 21.32 9.02 10.05 100.45 L. J. S. J. SCHETELIG (Centr. Min. 19 11 721-726).-This new mineral remarkable in containing scandium as an essential constituent occurb together with euxenite monazite beryl etc. in pegmatite new Iveland in Saetersdalen Norway. It forms radiating groups of large prismatic crystals (up to 25 cm. in length and 4 cm. in thickness) somewhat resembling epidote in appearance. The crystals are orthorhombic with a b c =PHYSIOLOGICAL CHEMISTRY. ii. 57 0.7456 1 1.4912 and are always twinned on the prism (llO) this being also a direction of good cleavage. The mineral is transparent to tranducent with a greyish-green colour and bright vitreous to adamantine lustre It is extremely brittle and the crystals are much tissured; H=6$; D 3.57.It is fusible only with difficulty and is partly decomposed by hot concentrated sulphuric acid. Partial and preliminary analyses gave SiO 42.86 ; R2”’OQ 57.67 (including about 3% Fe,O,) ; CaO,MgO traces ; loss on ignition 0.44 = 100-97. The oxides R;’O have mol. wt. 157.1 and consist mainly of scandia (about 37% SC,~,) with yttria dysprosia and erbia (about 17%) but no cerium earths The mineral is essentially a scandium silicate (Sc,Y),O 2Si0,. L. J. S. Minerals from the Deposits of Tiriolo (Catanzaro). U. PANICHI (Atti R. Accad. Lincei 1911 [v] 20 ii 518-523).-A pink fibrous zeolite has the composition of mesolite (I). Brandish (11) is found as white lamellar masses almost without action on polarised light. Crystals of fassaite are found and have been characterised by crystallographic measurements. These minerals are associated with calcite spinel idiocrase and garnet SiO,. Al,08. Fe,O,. CaO. MgO. Na,O. HzO. Loss. Total. I. 45.08 24.86 - 8.76 - 6’02 14’25 - 98.97 11. 22.83 48-20 5.38 2-53 21.78 - - 3.29 99.01 C. H. D.