MINERALOGICAL CHEMISTRY. Min era 1 ogi c a1 C h e mi s t ryl ii. 135 Volcanic Gases. ALBERT BRUN (Bec22. Soc. china. 1910 [iv] 7,4). -It is Dointied out that tbe use of the word ‘‘ fumarole ” in Gautier’s re-stateLent (Bull. Xoc. cfiinz. 1909 [iv] 5 982; compare Abstr. 10-2ii. 136 ABSTRACTS OF CHEMICAL PAPERS. 1909 ii 744 745) of the author's argument in favour of the view that aqueous vapour is of little importance in volcanic explosions (Abstr. 1907 ii 33) is confusing. T. A. H. Gas from Thermal Springs Presence of Krypton and Xenon. CHARLES MOUREU and A. LEPAPE (Compt. Tend. 1909 149 1171-1 174).-The authors have recognised the presence of krypton and xenon in twenty-six Prench thermal springs. The fact was established t h a t the gases did not come from the atmosphere in the w.0. w. Dawsonite a Sodium-Aluminium Carbonate. RICHARD P. D. GRAHAM (Trans. Boy. Soc. Canada [iii] 2 iv 165-177).-This mineral is found in two dykes in Montreal a t Thee Algeria and in Tuscany. Terminated crystals are very rare but the author found a few beloDging to the orthorhombic holosymmetric class [a b c = 0.6475 1 053391. Some very pure crystals on analysis gave vicinity of the springs. The optical properties mere studied. A1,0,. Na,O. CaO. MgO. co,. H,O. 35-70 21'62 1'59 trace 31-56 11.51 agreeing with the formula Al,P3,Na20,2C0,,2EI,0. A small amount of calcium was present as admixed calcite. Neither water nor carbon dioxide is lost at 140' ; long heating at high temperature is necessary to expel these constituents completely. Two constitutional formul~ are suggested ONa*Al(OH)*O*C!O*OH and Al(OH),*G*CO*ONa the first of which is considered the more probable.Chemical Investigation of a Uranium Mineral from Borneo. G. P. TSCHERNIK (Bull. Acad. Sci. Xi?. PGtersbourg 1909 [vi] 3 1203-1212).-This mineral occurs in well-formed iron-black crystals D16 9.057 hardness 5-6 exhibiting marked radioactive properties. The analytical results of two different specimens are as follows SiO,. UO,. UO,. PbO. Tho,. Y,O etc. CaO. FeO. 0.77 40.95 4124 8'51 5'03 1.56 0.18 0'91 0-76 40*58 41 15 8'49 5.00 1.57 0'18 0.90 trace trace - 0-52 99.67 9-059 - trace trace 0.52 99'45 9.056 These numbers show that the mineral consists of broggerite the corresponding formula being 4Si02,45U03,48U0 1 2Pb0,6Th0,,SY,03,C~0,4Fe0,9H,0.E. J. R. Bi,O,. MgO. Cud. H,O. Total. D'6. Further analysis of the rare earth constituent shows that it contains ytterhia and ceria in the proportion Y20 Ce,03 = 5 1 the cerin fraction containing oxides of cerium lanthanum neodymium and praseodymium in the proportioris Ce,03 La203 Nd,O Pr,O = 8 5 1 2. T. H. P. Isomerism in the Group of Alumino- and Ferri-silicates. WLADIMIR I. VERNADSKY (Bull. Acad. Sci. St. PZtersbourg 1909 [vi] 3 118~-1~02).-1n addition to alumino-(or ferri-)silicates having thePHYSIOLOGICAL CHEMISTRY. ii. 137 Rtructure of kaolinite (derivatives of clay) chloritoids (derivatives of M,AI,Si06) and chlorites [derivatives of A12Si2+m08+2m-fi( OH)2n or A1,Si0,,(OH)2,) a group of alumino-silicates is possibly derived from orthosilicates and having the general formula (M,SiO,),,qA where A =MA1,Si,08 (or MFe2Si20,) or MAl,SiO,. To this group belong (1) melilite (Ca,Si04)p,qCaA12Si,0s where p = 3.5 and q = 1.2 ; (2) gehlenite Ca,Si0,CaAl,Si06 and (3) ilvaite H,O - (Fe2Si0,)p - CaFe2Si20 where p = 2. In their properties these compounds differ from the compounds MAl,Si208 and approximate to the minerals M2Si0,. This series of silicates is analogous to the kaolinite series and to the granites isomeric with them. Isomerism in the kaolinite series is of three kinds (1) symmetry isomerism ; (2) transposition isomerism an example of which is shown by the granite CttA12Si20,(nucleus),Ca2Si04 and the member of the melilite series Ca2Si0,(nucleus),CtrAl2Si20 ; (3) isomerism of rearrange- ment as seen in lawsonite CaA12Si20 2H20 and Gibbsite H,A1,Si20,,Ca0,H20. T. H. P.