MINERALOGICAL CHEMISTRY.THE year 1911 has been remarkable for the gaps it has left inthe ranks of the workers in Mineralogical Chemistry. The deathof J. H. van’t IIoff in March last, will be felt as an irreparable lossto this as to other branches of science. The brilliant researchecon salt deposits, vhich he happily lived long enough to complete,will stand as one of many enduring monuments of his gpius. Anappreciation of hls work in this field, from the pen of H. E. Boeke,has recently been published.1 Notable figures have also passedaway in A. Michel LQvy a.nd M. H. N. Story-Maskelyne, thelatter the doyen of our science; a bibliography of his writings and ashort memoir have appeared in the Mineralogical Maynzine.2Among other workers we have to depiore the loss of E.Hussak,N. V. Ussing, and G. Spezia.The work that has been accomplished during the year, althoughlarge in volume, makes little call for special comment. The newminerals described have not been numerous. The most interesting,perhaps, are fermorite, an analogue of apatite containing arsenic;hinsdalite, a sulphato-phosphate of aluminium and lead ; andthortveitite, a silicate of scandium. Of the researches which havethrown light on the composition or constitution of known species,those relating to the clintonite group, to nepheline, schwartzember-gite, tilasite, parisite, and pearceite are among the most important.Considerable activity continues to be displayed in the study of thephysical-chemical problems which have bearings on mineralogy.Some of these will be noted below; we will only here call attentionto the work on the tercary systems C‘aO-Al,O,SiO, andAg C1-AgB r-AgI .Two important new publications have appeared during the year,I n the first place, we have to welcome Vol.I of a periodical entitled“ Fortschritte der Mineralogie, Kristallographie und Petrographie,”published by the newly-formed German Mineralogical Society. I nit will be found excellent summaries of recent progress in crystallo-graphy and mineralogy. The article on the application of theFortschritte der Mineralogie, Kristallographie ?Lnd Petrographie, 191 1, 1, 285.Nin. Mag., 1911, 16, 149.23MINERALOGICAL CHEMISTRY. 239phase rule to mineralogical problems, and the review of advancesmade in our knowledge of meteorites since 1900, will be foundworthy of special attention.The notes on new minerals describedsince 1898 lose much of their value in the absence of any referenceto the original sources. The second publication is an ambitiouswork entitled “ Handbuch der Mineralchemie,” edited by C.Doelter, assisted by a number of contributors. It seeks to give acomplete survey, not merely of our knowledge of the composition ofminerals, but also of the best methods of analysis and other cognatetopics. The plan of the work is excellent, but to judge by the fourparts which have so f2r appeared, and which are devoted mainlyto the treatment of the carbonates, its usefulness is likely to bemuch impaired by careless editing. Misprints, mis-spellings ofproper names, and false references are irritatingly frequent, andtend to shake the confidence of the reader in the general accuracyof the work.We may now proceed to the detailed treatment of oursubject, following in the main the order adopted in past years.General and Physical Chemistry of Miner&Silicate Fusions.-In the first place, we must notice that thetemperature determinations made up to the present by Day andhis colleagues a t the Geophysical Laboratory in Washington havebeen recalculated in terms of the nitrogen thermometer, and a tableof corrected values has been drawn up.3 The melting points ofdiopside, anorthite, and labradorite are now given as 1391°, 1550°,and 1477O respectively. Albite melts below 1200°, and the changefrom a-quartz t.0 @-quartz takes place a t 575O.A ternary system,lime-alumina-silica, has also been studied in this laboratory.4 Ithas already been shown that both the met& and ortho-silicates ofcalcium can be obtained from the lime-silica fusion, but no indi-cations of the existence of t’ricalcium silicate were observed. Ithas now been discovered that this compound if4 readily producedwhen alumina is added to the limesilica mixture of the propercomposition. This substance, which has been isolated in the nearlypure state, appears to be unstable at its melting point. It doecjnot form either eutectics or solid solutions with calcium orthosilicateor with lime. A new, and probably unstable, form of calciumorthosilicate has been discovered; and it has been shown that ferricoxide dissociates at about 1400O with formation of Fe,04, and doesnot form solid solutions with lime, tricalcium silicate, calcium ortho-silicate, or wibh 3Ca0,A1,03.These researches have an importantA. L. Day and R. €3. Sosman, Amer. J. Sci., 1911, [iv], 31, 341 ; A., ii, 496.E. S. Shepherd, G. A. Rankin, aud F. E. Wright, J. Ind. Eng. Chern., 1911, 3,211 ; A , ii, i 2 5 240 ANNUAL REPORTS ON THE PROGRESS OF CHEMLSTRY.bearing on the Portland cement industry. Several other workershave also been active in this field; thus E. Dittler 5 has discussedthe difficulties met with in finding the heating and cooling curvesof silicates, and using Doelter's methods, has performed illustrativeexperiments on diopside and on certain felspars, both natural andartificial.He points out that, owing t o the small velocity offusion, the absorption of heat a t the melting point is not the chieffactor in determining the shape of the heating curve. The valueshe adopts f9r the, temperatures at which the crystallisation ofanorthite and labradorite begins are some 350° lower than the melt-ing points given above. Another interesting research, which we oweto the same author: had for its object the study of the influence ofthe addition to orthoclase of small quantities of its lithium, rubidium,and caesium analogues. It was found that czsium had the greatesteffect in increasing the stability of the orthoclase and in promotingits crystallisation, which appears to take place at comparativelylow temperatures, 750-800O.I f larger quantities of the rubidiumor czesiurn compounds were employed, the mass ceased to be homo-geneous, and different kinds of crystals separated. From this itmay be inferred that miscibility can only take place within quitenarrow limits. Mixtur- of orthoclase and celsian and of orthoclasewith andesine were also examined.Some experiments with mixtures containing orthoclase have alsobeen carried out by C. Ne~bauer,~ who finds that in the case ofmixtures of artificial leucite, orthoclase, and diopside, melting beginsabout the fusion point of orthoclase, and ends a t a temperatureabout the mean of all three melting points. On studying thecrystallisation phenomena, he finds that the freezing points arelower than the melting points of any 01 the constituents, and thatleucite crystallises out first, followed by diopside.Crystals oforthoclase are not formed.These, however, are not the only silicates which have been studiedfrom this point of view. H. S. van Klowter,* in the course of anexamination of a number of binary mixtures, has studied thesystem Li,O-SiO,. He finds that both ortho- and metaAlicates oflithium are formed, and that the two compounds are but slightlymiscible. The melting point of the former he gives as 1243O, thatof the latter as 1188O. These values are very close to the figures,1215O and 1180°, given by Rieke and Endel1,Q who have studiedZeitsch. anorg. Chem., 1911, 69, 273 ; 2., ii, 96.Tsch. Min.Mitt., 1911, 30, 118.7 Fiild. Kodo~iy, 1911, 41, 197.8 Zcitsch. a?zo.q C'hem., 1910, 69, 135 ; A., ii, 111.It. Rieke arid K. Endell, APreclmm?, 1910, 43, 682 ; 44, 97 ; A . , ii, 490, 982MINERALOGICAL CHEMISTRY. 241the same problem. Yet a third valLze has been obtained for themelting point of lithium metasilicate by F. M. Jaeger,lo who makesit 1201-8O, that of the corresponding sodium salt being 1088O.The existence of lead metasilicate as a, stable compound has beendeduced by P. Weiller 11 from a study of the lead oxide-silica system.He failed to find evidence for the existence of the orthosilicate, andhis results are not altogether in harmony with those previouslyobtained by Hilpert and Nacken.12 The conditions of formation ofthe silicat,es of manganese have been examined in the same way.13Manganosite, MnO, was observed among the crystalline products,as well as tephroite, Mn,SiO,, and rhodonite, MnSiO,.The eutecticbetween the two latter lies at 1190O. The mutual relations betweenthe components of binary mixtures of silicates of different metalshave also been subjected to thermal analysis. It has been shown,for instance, that MgSiO, (m. p. 1535O) and MnSiO, (m. p. l2lo0>form a series of solid solutions, with a break at 1328O and 50molecules per cent. of MgSiO,. Crystals rich in magnesium showthe properties of enstatite, those rich in manganese resemblerhodonite. Calcium metasilicate, CaSiO, (m. p. 1512O), forms acontinuous isomorphous series of mixed crystals with the meta-silicate of barium, BaSiO, (m.p. 1438O). The freezing-point curvehas a minimum at about 35 molecules per cent. of BaSiO, and1 0 0 O O . Mixtures of the silicates of barium and manganese andof calcium metasilicate with calcium sulphide have also beenin~estigated.1~In this connexion it may be noted that R. B. Sosman15 hasstudied the published analyw of pyroxenes and pyroxenibe rocks,and has plotted the results on a diagram representing a three-component system composed of MgSiO,, CaSiO,, and FeSiO,. Hefinds that the rock analyses lie in a limited " eutectic field," withthe rhombic pyroxenes on one side and the monoclinic pyroxeneson the other, and he considers that the relations observed are inharmony with the experimental data of Allen and White.Salt Fusions-It is not, however, among the silicates only thatthe study of cooling curves has led to results of mineralogicalimportance, for a number of other binary systems have beenexamined, some of which demand attention here.Italian workers 16have been particularly busy in this field, and to them we owe ourlo J. Washington h a d . Sci., 1911, 1, 49 ; A . , ii, 981.l1 Chem. Zeit., 1911, 35, 1063 ; A., ii. 983.l2 See Ann. Report, 1910, 227.l 3 F. Doerinckel, Metallurgie, 1911, 8, 201 ; A., ii, 608.14 P. Lebedeff, Zeitsch. anorg. Chem., 1911, 70, 301 ; A., ii, 604.lB J. Washington Acad. Xci., 1911, 1, 54 ; A . , ii, 992.-See papers by Sandonnini and others in Atti R. Accad. Lincei, 1911, [v], 20.REP.-YOL. VIII 24.2 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.knowledge of the behaviour of mixtures of a number of chlorides ofunivalent and bivalent metals.Some of the bivalent chlorideshave also been examined by 0. Menge,l7 whilst W. Botta 18 has madea study of the system NaCl-AgCl. He finds that the solidificationpoints of mixtures of silver chloride and salt vary continuouslybetween that of the pure silver compound melting a t 460° andthat of salt melting a t 792O. The crystalline masses which resultappear to be homogeneous. The mineral huantajayite, containing11 per cent. of silver chloride, may be regarded as a member of thisseries.These results have been confirmed by C. Sandonnini,lg who hasalso found that if lithium chloride is substituted for salt, two kindsof crystals are obtained.I n the hope of throwing some light on the nature of the mixedsilver halides which occur as minerals, F.MatthesZ0 has made avery complete study of the complex relations of the ternary systemAgC1-AgBr-AgI. His results lend no support to the view thatiodobromite, 2AgC1,2AgBr,AgI, exists as an independent species,for no compound of all three components could be got from themelt. Two kinds of mixed crystals were, however, obtained. Thefirst form a continuous series, and consist almost entirely of silverchloride and silver bromide, with quite inconsiderable quantities ofsilver iodide. The second are ternary mixed crystals, and containsilver iodide as an essential constituent. Pure silver iodide wasnot observed as it product; in any of the melts.The compositionsof the iodembolites analysed by Prior and Spencer are not inharmony with the results of these experiments, and it is suggestedthat their crystals were not perfectly homogeneous, but may haveconsisted of a core rich in silver chloride and bromide, surroundedby a shell containing more silver iodide and bromide. The ternarysystem formed by the three halides of lead has also been studiedby the same author.The conditions under which mixed crystals of sodium andpotassium sulphates are formed, both from fusions and from aqueoussolutions, have been examined by R. Nacken.21 He has found thatwhen fused mixtures are cooled, hexagonal modifications of thesalts separate first, which form a complete series of mixed crystals.As the temperature falls, these crystals undergo change, but theproduction of hexagonal mixed crystals identical with those result-ing from aqueous solution at low temperatures is confined to certainl7 Zeitsch.anorg. Chem., 1911, 72, 162 ; A . , ii, 982.lY Atti 8. Accad. Lincei, 1911, [v], 20, i, 758.2o Jahrb. Min. BciZ. Band, 1911, 31, 342; A . , ii, 476.‘L1 Satzungsber. K. Akad. llriss. Berlin, 1910, 1016 ; A., ii, 109.Centr. Min., 1911, 138 ; A., ii, 293MINERALOGICAL CHEMISTRY. 243concentrations, the limits being glaserite, Na2S0,,3K,S0,, on theone side, and 49 per cent. of potassium sulphate on the other.From aqueous solutions containing excess of potassium sulphate,glaserite and potassium sulphate separate, but when exceas ofsodium sulphate is present, mixed crystals composed of glaseritewith sodium sulphate occur, together with the latter salt.Growth'and Solution of Crystals.-It has long been known thatthe presence of irr,purities in the solution of a crystallisable sub-stzncs will influence the habit of the crystals which separate.Anotable instance of this is found in the behaviour of salt, which isobtained in cubes from pure aqueous solution, but appears inoctahedra from solutions to which carbamide has been added.Some light has lately been thrown on this curious phenomenon bythe determination of the rates of solution of salt on natural andartificial faces when exposed t o the action of unsaturated saltsolutions of various strengths.22 The rate of solution was found tovary with the degree of under-saturation.Moreover, when watercontaining salt only was used, material was removed slightly fasterfrom the octahedron faces than from those of the cube, but whencarbamide was added to the solution, this relation was reversed.Observations on growth and solution have also been made onother substances; thus, in the case of gypsum,2s the velocity ofsolution varies considerably on different faces, the relative valuesfor tha three common forms, {OlO}, {110}, and { l l l } , being1 : 1.76 : 1.88 respectively.In the case of the alums,24 the habit .may be considerablyinfluenced by adding hydrochloric acid t o the solution. If a littleis added, the forms (211) and (201) appear; further addition ofhydrochloric acid causes (201) t o increase. The behaviour ofmeconic acid and of artificial crystals of barytes 26 has also beenstudied from the same point of view, and it has been &own thatthe power possessed by some salts of taking up organic dyestuffsis an absorption phenomenon.27Transformation of Polymorphous Sub stances.-Somewhat dis-cordant statements are current aa to the heat-change which accom-panies the transformation of aragonite into calcite, and SLS t o thetemperature a t which the change takes place.It would nowappear that the temperature of transformation lies between 465Oand 470°, a sudden change in the density of aragonite occurring22 A. Ritzel, Zeitsch. Kryst. &fin., 1911, 49, 152 ; A., ii, 488.S. Tottoczko, Bull.Acad. Sci. Cracow, 1910, 209 ; A., ii, 24."A Z. Weyberg, Chem. Zentr., 1910, ii, 1026 ; A., ii, 263.P. Gaubert, Compt. rend., 1910, 151, 1134 ; A., ii, 101.26: H. Gerhart, Tsch. &fin. Mitt., 1910, 29, 185 ; d., ii, 262.27 R. Marc, Zeitsch. yhysikal. Chem., 1911, 75, 710; A . , ii, 193.R 244 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.about this point.98 Measurement of the amounts of heat given outon cooling calcite and aragonite which had been heated to varioustemperatures led to the conclusion that +2*72 cals. per gram-molecule represents the heat-effect of the change. This numberagrees with that obtained by Favre and Silbermann. Theresults of thermal analysis have established the existence of twokinds of quartz, termed a-quartz and &quartz respectively, thereversible transformation from one form into the other taking placeat 575O.The indices of refraction of quartz have lately beendetermined at various temperatures, ranging from - 140° to + 765O,and the existence of these varieties is confirmed by the discoveryof a well-marked break a t 57Oo.z9 I n the case of leucite, a substancewhich is birefringent at the ordinary temperature, but becomes iso-tropic at 7 1 4 O , the refractive index curve alters its direction; itshows, however, no sudden discontinuity, the change taking placeover a considerable temperature interval.Water of Crystallisation.-A few years ago F. Zambonini so con-tributed to the pages of an Italian periodical a very voluminousdiscussion of the part played by water in minerals.He has latelypublished in German a full abstract of this work.31 His contentionis that we must distinguish between water of constitution orcrystallisation on the one hand, and dissolved or absorbed wateron the other. He maintains that it is possible to make this dis-tinction with certainty by studying the course of dehydration. Asthe result of numerous experiments, he concludes that manyminerals, formerly believed to contain water of constitution, reallycontain absorbed water, and that many substances, such, forexample, as prehnite and apophyllite, contain variable quantitiesof dissolved water in addition to water of constitution.Some very interesting observations on the passage of waterthrough certain crystals containing water of crystallisation havebeen made by H.B. Baker and G. H. J. Adlam 32 during the courseof an investigation into the constancy of composition of such sub-stances. Phosphoric oxide was placed in small flasks, which werethen closed by crystal plates sealed into their mouths with paraffin.Flasks closed with plates of anhydrous crystals, such as anhydrite,CaSO,, potassium chlorate, or telluric wid, showed no change inweight after exposure to a moist atmosphere for some weeks. Onthe other hand, flasks closed by plates of gypsum, or of hydratedcopper sulphate, barium chloride, and potassium ferrocyanide2’J 1’. N. Lnschtschenko, J. Ems’. Phys. Chem. SOC., 1911, 43, 793 ; A . , ii, e86.m F. Itione and R. Kolb, Ja7~rb.Min., 1910, ii, 138 ; A . , ii, 209.Atli I?. Aecnd. Sci. Fis. Mat. A-apoli, 1908, 16, 1-127.31 Zeilseh. Kryst JfiH., 1911, 49) 73.s2 TraTls., 1911, 99, 507MINERALOGICAL CHEMlSTRY. 245showed very perceptible increases, proving that in these cases waterhad been transmitted by the crystal.Pressure and Chemical Change.-Van Hise has suggested thatunder the influence of very high pressures, silicates may be formedfrom silica and carbonates, water may be squeezed out of hydratedminerals, and combined oxygen may be removed in the same way.G. Spezia 33 has attempted to confirm these views experimentally,but without success. Thus calcium carbonate and hydrated silicadid not react when subjected t o a pressure of 6000 atmospheres fora year. Limonite, alabaster, and alum, exposed to a pressure of 8000atmospheres for eight months a t 15--24O, were not dehydrated, norwere crystals of gothite affected by keeping them for twenty-sixdays under a pressure of 9500 atmospheres.Calcite and aragoniteremained unchanged after exposure to a pressure of 7000 atmo-spheres for six months.Chemical Crystallography .The two most important investigations undertaken in this fieldduring 1911 are the study of the isomorphism of indium andthallium made by R. C. Wallace34 and the elaborate examinationof derivatives of the quaternary ammonium bases which we oweto A. Ries.36 The salts of the type K3T1C1,,2H,0, of which fivewere examined, crystallise in the holohedral class of the tetragonalsystem. Thme of the type Rb,T1Cl,,H20 are orthorhombic andisomorphous with the potassium and ammonium salts of thesame type containing iron.KT1Br4,2H,0, (NH4),TlBr4,2H,0,RbT1Br4,H,0, and CsT1Br4 are all cubic. So far as habit is con-cerned, the alkalis stand in the order: ammonium, rubidium,oaesium. Chlorine and bromine salts are very similar. On theother hand, the substitution of iron or indium for thallium producesmarked changes. The angles vary in a slightly different order,ammonium salts lying between those of rubidium and caesium, butnearer t o the former. The substitution of caesium for rubidium,or of bromine for iodine, produces about equal effects. Largereffects are observed when indium or thallium is substituted foriron, the changes being roughly proportional to the alteration inthe atomic weights.As regards molecular volumes and topic axes,the alkalis form the series K, NH,, Rb, Cs, ammonium and rubidiumbeing close together. Substitution affects chiefly the x and 3/values. Substitution in the iron, indium, thallium group has littleinfluence, but indium is more closely related to thallium than toiron.Atti R. Accad. Sci. Torzno, 1911, 46, 682 ; A., ii, 903.3i Zeitsch. Kryst. Min., 1911, 49, 417 ; A., ii, 890. ;jS llbid., 513246 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.It is impossible to do justice to the very comprehensive workof Ries in the short space at our disposal. Suffice it to say that i tconsists of a discussion of the chlorcl and bromo-platinates andstannates of a very large number of substituted ammonias, severalof which have been especially prepared for the purposes of thisinvestigation.The relations exhibited by these substances are verycomplex, for, although the crystals a t first sight apparently exhibitonly simple forms of the cubic system, i t is found on furtherinvestigation that a number of polymorphow forms exist whichare often either pseudo-cubic or belong to different sub-classes ofthe cubic system.The researches of Tutton have shown that in the series comprisingthe sulphates 'and selenates of the alkali metals and the doublesulphates and selenates of the type M2/SO4,Ml/SO4,6H2O, thecrystallographic properties of the rubidium salts are intermediatebetween those of the potassium and caesium compounds, and thatthose containing ammonium find a place between the rubidium andcsesium salts.F. M. Jaegers6 maintains that this regularity is notuniversal and does not hold in other groups, the morphotropicrelations of the alkali metals being in reality very complicated.As an illustration of this he quotes the salts of trichloroacetic acidof the type CC13-Cf102K,CC13*C02H, which form an isopolymorphous,in all probability isotetramorphous, series with three monoclinic andone trapezohedral tetragonal modifications. The potassium andammonium salts are tetragonal, the rubidium salt exhibits one ofthe monoclinic forms, the czsium compound the two others, thecommoner of the two being pronouncedly pseudo-tetragonal. Thethallium salt is tetragonal.Among minor investigations we may notice the following.H.Baumhauer 37 has continued his examination of the optical andcrystallographic character of the platinum double cyanides, and hasalso studied the picrates of potassium and ammonium. L. Wagner 39has measured the formates of calcium and strontium; the formersalt is rhombic &pyramidal, the labter irhombic bisphenoidal.Attempts to make mixed crystals gave results which led him toconclude that these salts are isotrimorphous. The double chromatesof magnesium with msium and rubidium have been prepared byT. V. BarkerFO who finds that they are isomorphous with the corre-sponding sulphates, and the polymorphism of the phthalylhydrazides,prepared by F. D. Chattaway and D. F. S.Wiinsch, has beenstudied by the =me author.4036 Proc. K. Akad. Wetcnsch. Amsterdam, 1911, 14, 356.87 .Zeitsch. Kryst. Min., 1911, 49, 113 ; A., i, 431.89 Trans., 1911, 99, 1326.38 Ibid., 50, 47.'O Ibid., 2263MUVERALOGICAL CHEMISTRY. 247The crystals of some fluorides, silicides, carbides, and borides,prepared by Moissan and his pupils, have been measured by A. deSchulten.41Artificial Formation of Minerals.A number of minerals have been obtained in minute crystals byheating silica, alumina, lime, potash, or soda with water in a steeltube for twelve to sixteen hours a t 350° or 450°.42 The products,which were identified microscopically, include quartz, orthoclase,albite, oligoclase, analcite, stilbite, andalusite, pyrophyllite, andmuscovite, the occurrence of the three latter being especially worthyof note.Isomorphous mixtures of the carbonates of calcium, mag-nesium, and iron have been prepared by mixing solutions of calciumchloride, magnesium chloride, magnesium sulphate, ammoniumsesquicarbonate, a.nd ferrous ammonium sulphate.43 Gelatinous precipitatm are formed, which after a time crystallise. From analysesof the products, it would seem that under these conditions iron andcalcium mix in all proportions, but that only small quantities ofmagnesium are taken up. This is in harmony with the observationthat when a magnesium-calcium carbonate is placed in ferroussulphate, the magnesium is replaced by iron more quickly than thecalcium.Artificial crystals of barytes of some size have been obtained bycrystallisation from fused barium chloride and sodium sulphate.44A somewhat similar process has resulted in the preparation of anumber of artificial apatites, a tribasic arsenate or phosphate beingfused with the chlorides of calcium, strontium, barium, or cadmium,or with cadmium bromide.On measuring the hexagonal crystals,it was found that the value of c diminishes when either themetal or the halogen is replaced by another of higher atomicweight, and that a similar change takes place when arsenic is sub-stituted for phosphorus.46The chlorine analogue of spodiosite, C%(PO&,CaF,, can also beobtained in a similar ~ a y , ~ 6 but apparently requires a lower tem-perature for its production, as on heating to redness, apatite wasobtained.This observation explains the rare occurrence ofspodimite in nature.‘I Compt. rend., 1911, 152, 1107, 1261 ; A., ii, 486, 605.42 E. Bauer and F. Becke, Zeitsch. anorg. Chem., 1911, 72, 119 ; A., ii, 991.43 W. Diesel, Zeitsch. Kryst. Min., 1911, 49, 250 ; A., ii, 725.44 H. C. Cooper, T. S. Fuller, and A. A. Klein, J. Amer. Chem. Soc., 1911, 33,45 A. de Schulten, Compt. rend., 1911, 152, 1404; A., ii, 615.UI F. K. Cameron and W. J. McCaughey, J. Physical Chenz., 1911, 15, 463;845 ; A., ii, 726.A., ii, 734248 ANNUAL REPORTS OK THE PROGRESS OF CHEMISTRY.The formation in nature of smithsonite, ZnCO,, has been imitatedby G . P i ~ l t i . ~ ~ He suspenc‘ed a rhombohedron of calcite in asolution of zinc sulphate, and after the lapse of seventeen and a-halfyears found it coated with mamillary zinc carbonate and withcrystals of gypsum.A solution of potassium nitrate left in contactwith zinc blende was found to contain sulphate,and fragments ofgalena similarly treated were found to be coated with crystals ofanglesite, PbSO,, nitrite being detected in the solution.iVew Minerals.3 chZusite.-This substance is an alteration product of t0pa.z fromthe Shepherd and Murphy Mine, Tasmania, where i t occursassociated with fluorite, cassiterite, wolframite, and topaz.48 Inappearance it resembles steatik.Baba6udam’te.-This somewhat uncouth name has been proposedfor a soda-amphibole, allied to riebeckite, which occurs in black,radiating, prismatic aggregates associated with cummingtonite inthe quartz-magnetite-schist of the Bababudan Hills, Mysore.49 Thecleavage angle is 56*, and the extinction angle somewhat greaterthan that of riebeckite, from which it differs also in pleochroism.Analysis leads to the formula 2NaFe”~(Si0,),,Fe~~Mg3(Si03),.BatcheZorite.-This has been described as a new species in arecently published list of the minerals of Ta~rnania.5~ It is ahydrated silicate of aluminium, apple-green to greenish-grey incolour, and occurs massive at the Mt.Lye11 Mine, Tasmania. Thecompmition is as follows:SiO,. A1,0,. H,O . Total. Sp. gr.49 ’4 45 ’1 5-6 100.1 3 -3Beawerite.-This mineral occurs as very minute, hexagonal plates,forming a canary-yellow, earthy-looking mass a t the Horn SilverMine, near Frisco, Beaver Co., Utah, where it is found with othersecondary minerals in the upper part of the deposit.51 On analysis,its composition was found to agree well with the formula4Cu0,4Pb0,3Fe,03,A1,0,,8S0,,16H,0, which redeces toCL~O,P~O,F~,O,,~SO,,~H~O,if the aluminium is regarded as replacing a portion of the iron.Eichb erg&.-A single specimen of an iron-grey, massive mineralhas been found embedded in magnesite at Eichberg, on the47 Atti R.Accad. Sci. Torino, 1911, 46, 783 ; A . , ii, 902.48 W. F. Petterd, Proc. Roy. SOC. Tasmania for 1910, 191.49 W. F. Smeeth, Records Mysure Ceol. Dept., 9, 85-94; A., ii, 737.60 R. F. Petterd, Proe. Roy. Soe. Tmmania f o r 1910, 22.5l B. S. Butler and W. T. Schaller, Amer. J. Sci., 1911, [iv], 32, 418MINERALOGICAL CHEMISTRY.249Semmering Pass.52gram of selected material, agree with the formula:The results of an analysis, made on half a(Cu,Fe),S,3(Bi,Sb),S3The specific gravity is 5-36,Ep'nat?-olite.-As the result of a study of the natrolite from aquarry in the neighbourhood of Schomitz, near Carlsbad, Thugutt 53has come to the conclusion that two metameric varieties of thismineral exist. In both the crystal form, the optical properties,and the chemical composition are the same, but, on heating, oneis more stable than the other. This is shown by igniting the finelypowdered mineral for a few seconds, and then adding solutions ofmethylene-blue or of silver nitrate followed by potassium chromate.The colour effects produced get weaker the longer the heating wascontinued.The less stable variety, for which the name epinatroliteis proposed, is common in phonolites, and is believed to be a decom-position product of a member of the sodalite group. The morestable variety is believed to be derived from nepheline.Fermo&e.-This interesting mineral occurs m veins of palepinkish-white or white material in the manganese ore of Sitapar,Central Provinces, India.54 The optical characters and the presenceon one specimen of a prism of 60° indicate hexagonal symmetry, aconclusion supported by the chemical composition, which conformsto the apatite type, agd may be represented by the formula3[(Ca,Sr)3(P,As),0,],Ca(OH,F),. The mineral has been namedafter L. L. Fermor, to whose elaborate investigations of the Indianmanganese deposits we owe our knowledge of juddite, sitaparite,hollandite, etc.Ferriferous Garb orundum,.-A metallic-looking substance, D 6-7,from the pulsator residues a t the Du Toits Pan Diamond Mine,Kirnberle~,~5 was found on analysis to agree approximately with theformula Fe,,Si7C7.It has not been found in situ, and is probablynot an original constituent of the " blue ground," but an artificialproduct.Ferritungstite is an alteration product of wolframite, found atthe Germania tungsten mine in the Deer Trail mining district ofWashington.66 In appearance i t is a pale yellow or brownish-yellowochre, which, under the microscope, is seen t o consist of minute,hexagonal plates. The analytical results lead to the formulaFe,O,,W 03, 6H20.5'2 0.Grosspietsch, Centr. Min., 1911, 433 ; A . , ii, 807.53 St. J. Thugutt, ibid., 405 ; A., ii, 736.54 G. F. Herbert Smith and G . T. Prior, Min. May., 1911, 16, 84 ; A . , ii, 1103.55 J. K. Sutton, Natwre, 1911, 87, 314.56 W. T. Schallcr, Amer. J. Sci., 1911, [iv], 32, 161 ; A . , ii, 903250 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.Ga>te.--This mineral closely resembles magnesite in appearance,is apparently homogeneous, and, t o judge from its cleavage andoptical characters, belongs to the group of rhombohedral carbonates.57It occurs in limestone near Plr'ice, district of Gorski kotar, inCroatia. It dissolves readily in acids, and has the composition:CaO. MgO. co,. H,O. Total. Sp. gr.37'08 23.85 32.34 6.67 99'94 2.619Hexahydrite.-A course coiumnar or fibrous mineral occurs inseams or patches in an altered schistose rock in the district ofLilloet, British Columbia.It is readily soluble in water, and onanalysis was found to have a composition agreeing very closely withthe formula MgS0,,6H,0.68 The specific gravity (1.757) is some-what greater than that (1.734) recorded for the monoclinic crystalsof the artificial salt of the same composition.HinsdaZkte.-An interesting mineral, found at the Golden Fleecemine, near Lake City, Hinsdale Co., Colorad0.6~ It has the com-position 2Pb0,3A1,0,,2S03,P20,,6H20, and is therefore closelyrelated to svanbergite, the corresponding strontium compound,which appears to occur with it in isomorphous mixture, and tocorkite, in which ferric oxide plays the part of alumina.Likethese minerals, it belongs to the rhombohedral system, the crystalsbeing rhombohedra approaching cubes in shape, m'= 91°18', andhaving a basal cleavage. Viewed in polarised light, the crystals areseen to exhibit anomalies, a positive uniaxial centre being sur-rounded by biaxial sectors. The refractive indices are a = 1.670,B = 1.671, y = 1.689.LubZimite.-A name given to a variety of calcite found in felt-like masses in crevices in chalk-marl at Wysokie, Govt. Lublin,Russian Poland.boiKoZengraafite.-Small, yellowish-brown prisms, probably of mono-clinic symmetry, occur as a constituent of lujaurite, a rock of thenepheline-syenita group, in the Pilaadsberg, Transvaal.61 Theyexhibit a perfect cleavage parallel t o the orthopinacoid, and therefraction and birefringence are high (a = 1-735, y = 1.770).Theircomposition, as determined by Pisani, is as follows:SiO,. T10,. A1,0,. Fe,O, FcO. MnO. CaO. MgO. N+O. K,O. H,O. Total.28-90 27.70 3'75 0.95 2.07 2.72 19'00 2-38 10.30 0-60 1-00 99-37S q . gr. = 3'65.57 Fr. Tuhn, Centr. Mi%., 1911, 312 : A., ii, 498.58 A. A. Johnston, Summary Report Geol. Survey Branch Dcp. of Mines, Canada,59 E. S. Larsen, jun., and W. T. Schaller, Amer. J. Xci., 1911, [iv], 32, 251 ;6o J. Morozewicz, Zeitsch. Kryst. Mi%., 1910, 48, 622; A . , ii, 121.1911,256.A., ii, 1102.H, A. Brouwer, Centr. Min., 1911, 129 ; A,, ii, 296MINERALOGICAL CHEMISTRY. 251Morgn~tite.-This name has been suggested for the rose-pinkberyl from California, which is suitable for use as a gem.62 It is,however, hard to discover what useful scientific purpose is served byassociating the name of an American millionaire with a particularoccurrence of a well-known mineral.Muthmanmite.-The tellurides of gold and silver grouped togetherunder the name krennerite differ somewhat widely in composition,and Zamboniniw proposes to establish a separate species under thename muthmunnite for those of the type (Ag,Au)Te, containingabout 20 per cent.of silver, retaining the name krennerite for thoseof the type [Au(Ag)]Te,. of which the silver content is small. Aspecimen of the former mineral from Nagyag consisted of imperfectcrystals elongated in one direction, parallel t o which there was agood cleavage.The crystals were pale brass-yellow in colour, andwere found on analysis to contain 26.36 per cent. of silver, and tohave the formula (Ag,Au)Te.64Natram6 lygonjte.-The mineral occurs massive in pegmatite nearCanon City, Colorado.65 It resembles amblygonite in appearance,but contains much sodium (Na,O=11.23 per cent.), and but littlelithium (Li,O = 3-21 per cent.).(Na,Li)Al(OH,F)PO,,analogous to that of amblygonite.Neocolemanit e.-A mineral forming a considerable deposit, inter-bedded with black, carbonaceous shales, near Lang, Los Angeles Co.,California, has been termed neocolemanite on account of slightdivergences in its optical and crystallographic properties fromthose of colemanite, with which it otherwise appears t o beidentical.66 It would seem, however, that these divergences vanishif a slightly different orientation be given to the crystals, the faces001, 010, and 100 of neocolemanite being taken as 001, 010, and201 of colemanite.Poechite.-A manganese ore of the composition H,6Fe,Mn,Si30,9occurs at Vares, in Bosnia.I n colour it is red to chesnubbrown,and is believed to represent a new species.678tewartite.-A name proposed for a variety of bod, apparentlycontaining metallic iron, from the Kimberley diamond mine8.mStitchtite.-Occurs in irregular masses and veins of a rose-pink82 G. Kunz, Amer. J. Sci., 1911, [iv], 31, 81.The formula is-F. Zambonini, Zeitsch. Kryst. Min., 1911, 49, 246; A., ii, 734.C.Gastaldi, Rend. Accad. Sci. Fis. Mat. Napoli, 1911, [iiia], 17, 24 ; A., ii,W. T. Schaller, Amcr. J. Sci., 1911, [iv], 31, 48 : A., ii, 121.901.t3a A. 5. Eakle, Bull. Dcp. GcoL Univ. Catvorniffi, 1911, 6, 179; A., ii, 901.~7 F. Katzer, Chent. Zentr., 1911, i, 1660.68 J. R. Sntton, Nature, 1911, 87, 660252 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.to deep purple colour in serpentine at Dundas, Tasmania. Underthe microscope it appears to consist of strongly birefringent fibresand tufts sometimes radially disposed about nuclei of chromite.The composition is as follows:Cr,OB. Fe,O,. MgO. CO,. H,O. Total. Sp. gr.11.5 9.0 36.0 7-2 36‘1 99.8 2.12The mineral dissolves with effervescence in hydrochloric acid,affording an intensely bright green solution.It was formerlymistaken for kammererite, a member of the chlorite group.69!Z’ltortveitite.-This remarkable mineral was found in pegmatitein Iveland, south Nor way, associated with euxenite, monazite, andberyl. It forms rosettes of radial structure, some of the individualsreaching considerable dimensions. The system is orthorhombic,a: b : c=0*7456: 1 : 1.4912. The forms present are 111, 211, and110, the latter being a plane of cleavage and twinning. Thecrystals are greyish-green in colour, and translucent to transparent.The plane of the optic axes is 010, the acute negative bisectrixbeing perpendicular to 001. The mineral exhibits strong refraction(a = 1.7625 greer,) and birefringence. Its specific gravity is 3.57.Preliminary analyses have led to the interesting conclusion that thecomposition of the mineral is RJ//0,,2SiO2, where R/’/ stands forscandium and metals of the yttrium group, the former largelypreponderating. A direct determination of the scandium gaveSc,O,=37 per cent.The mineral is therefore a scandium ~ilicate.7~“aterite.-This name has been suggested for an unstable varietyof calcium carbonate, which usually occurs as spherulites, althoughsometimes in optically biaxial needles. It is distinguished fromaragonite by its lower specific gravity (2.6 about) and weakbiref r i n g e n ~ e . ~ ~PttrofZzcorite.-The mineral occurs in pegmatite in northNorway.72 It is isotropic, and possesses imperfect octahedralcleavage. The physical characters and composition vary slightly indifferent specimens.One sample of density 3-557 and refractiveindex 1-4572 (sodium light) gave, on analysis, results agreeing withthe formula 20CaF2,3YF,.I n addition to the above, investigations have been published ofa few other substances, some of which may prove to be new minerals.Among them we may notice a titano-tantalate of rare earth metals,from the State of Espirito Santo, Brmil,73 a,nd two hydrated69 W. F. Petterd, Proc. Roy. SOC. Tasmania for 1910, 167.7u J. Schetelig, Cemtr. Min., 19i1, 721 ; A., 1912, ii, 56.7l Tide C. Doelter’s Bandbatch der Mineralchemie, I , 113.72 T. Vogt, Centr. Min. , 1911, 373 ; A., ii, 733.yy J. M. de Padua e Castro, Revista Chim., 1910, 6, 365 ; A., ii, 735MINERALOGICAL CHEMISTRY.253silicates of aluminium allied to allophane from the neighbourhoodof Aywaille, Belgium.74 The first of these latter may be representedas A1,O3,Si0,,7$R20, and is easily attacked by acids; the secondhas the formula 4A1,0,,5Si0,,15H20, and resists the action of acids.Mineral Analyses.-4 egirit e.--Good, blackish-green crystals approximating closely tothe theoretical composition N+Fe,Si,O,, occur in pegmatite in theQuincy granite, Mass., U.S.A.76 The axial ratios are a : b : c=1.1044 : 1 : 0.6043 ; p = 73O27’. The crystals are pleochroic, and theextinction angle is 6O.A1lophane.-The nature of the hydrated aluminium silicates,aJloplzane, halioysit e, and montmorillonite, has often been discussed ;and while, on the one hand, the individuality of these species hasbeen maintained, it has been held, on the other, that theyare merely loose combinations or mixtures of colloidal silicic acidwith colloidal alumina.St. J. Thugutt76 finds support for theformer view in the behaviour of these substances towards organicdyestuffs, but his conclusions have been traversed by H. Stremme.77Alunite Group.-A useful discussion of this group has lately beengiven by W. T. Schaller.78 The numerous minerals composing thegroup are all rhombohedral, and may be represented by the generalformula [R’//(OH),],R/I[M],[MJ. They may be conveniently dividedinto three sub-groups, of which alunite, hamlinite, and beudantitemay be taken as types. It is suggested that goyazite is identicalwith hamlinite ; and apatelite, raimondite, pastreite, cyprusite, andutahite are all united with carphosiderite, t o which the formulaH,0,3Fe,0,,4S0,,6H20 is assigned.An analysis of alunite, found in liparite, has been publishedby U.Panichi.79A tacam’te.-H. Ungemach 80 has made an elaborate crystallo-graphic examination of this mineral, and has observed a numberof new forms. He adopts the orientation given by Phillips and byLQvy, and finds a: b : c=0*87808 : 1 : 1.32710. He regards thepratacamite of G. F. Herbert Smith as a complex twin of ordinaryatacamite. Analyses of material from Antofagasta and from Boleogave results agreeing closely with one another and with the formulaCuCl2,3Cu(OH),.74 G . Moresske, Bzd1. Xoc. gboob. Belgique, 1911, 37, 2 i 0 .75 C.Palnche and 0. H. Warren, Amer. J. S’ci., 1911, [iv], 31, 533 ; A . , ii, 614.76 C‘entr. Min., 1911, 97, 276; A . , ii, 210, 501.77 Ibid., 205; A., ii, 406.78 Amer. J. Sci., 1911, [iv], 32, 359; A., ii, 1101.79 Atti R. Accad. Lincei, 1910, [v], 19, ii, 656 ; A . , ii, 210.8o BuW. SOC. franq. Min., 1911, 35, 148 ; A,, ii, 1100254 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.Bauxite.-An account of the occurrence and employment incommerce of this mineral has been given by A. Gautier.sl Thevariations in its composition are illustrated by analyses.Bertmndite.--The chemical formula, H,Be,Si20,, of this raremineral has been confirmed by the analysis of good material fromIveland, South Norway.82 The crystallographic and optical charac-ters were hlso determined.The optic axial plane is parallel to 010,and the obtuse bisectrix perpendicular to the base. 2V=74O41',and a= 1.5914, P= 1.6053, y = 1.6145 (all for Na light). Sp. gr. =2.597.Beryl.-Much attention has been paid of late to the beautifulberyls which occur in the pegmatites of Madagascar, and it wouldappear that two types can be recognised.83 One, ordinary aqua-marine, of prismatic habit and exhibiting but few faces; the otherof tabular habit, and rich in faces. Crystals of the second typecontain considerable quantities of alkali metals, particularly ofmsium, and are denser than those of the first type, and havehigher indices of refraction. Lacroix,84 however, has pointed outthat so far as composition is concerned, the analyses hitherto pub-lished indicate the existence of a continuous series of compoundswith corresponding gradations in density and refractivity.Bismath Ochre.-Amorphous bismuth ochres occur at Pala, SanDiego Co., California. A grey sample was found to consist mainlyof bismuth hydroxide.A yellow specimen had the composition ofpucherite, BiVO,, whilst another yellow specimen proved to be amixture of vanadate and hydroxide. These results tend to confirmthe view that natural bismite is a hydroxide.85Bismutoslvhnemte.-Analysea of this rare mineral published byS. D. Kusnetzoff 86 agree fairly well with the formula Bi,CO,.BZende.-The well-known transparent yellow blende fr6m Picosde Europa was found, on spectroscopic examination, to containindium, gallium, and germanium.Iron was present in --ery varyingproportions in all the specimens examined; one which was nearlycolourless contained 0.066 per cent. of ferrous sulphide only.Water extracts traces of the chlorides of calcium, potassium, sodium,and lithium from the fineiy powdered mineral.8781 Rev. g h . C'Iuirn. pure appl., 1910, 13, 389; A., ii, 497.82 T. Vogt, Zeilsch. Kryst. Min., 1911, 50, 6.L. Duparc, M. Wunder, and R. Sabot, Bull. Soc. franq. Min., 1911, 34, 131,A. Lscroix and E. Rengade, ibid., I23 ; A . , ii, 736. See also A m . Report239 ; A., ii, 1105.for 1910.85 W. T. Schaller, J. Amer. Chem. Soc., 1911, 33, 162; A., ii, 293.u7 R. Llord y Gamboa, Anal. Fis. Quim, 1910, 8, 413 ; A . , ii, 733.Bull. h a d . Sci. St. P&ersSou?+g, 1911, 8%' ; A., ii, 1104MINERALOGICAL CHEMISTRY.255Blomstrandine.-Black crystals in pegmatite from Miask, sup-posed ta be aeschynite, have proved, on analysis, to be identicalwith Brogger’s blomstrandine, a titanol-columbate of yttriumearths.88BZomstrundite.-A massive mineral of greenish-brown colour,found in pegmatite a t Ambolotara, Madagascar, was found onanalysis to be a uranif erous columbo-titanate similar in compositionto the substance from Nohl, Sweden, described by Lindstrom underthe name blomstrandite in 1874.69 It must not be confused withblomstrandine.CaEaverite.-It is interesting to notice that a study of the freezing-point curve of the system gold-tellurium has shown the presenceof a maximum corresponding with the compound AuTe2, melting a t464O.There are also two eutectic points at 4 1 6 O and 447O respec-tively, corresponding witlh 12 and 47 atomic percentages of gold.There is no indication of the formation of solid solutions.90.Cancrird e.-A reexamination of the material from Brevig,Norway, analysed by Lemberg in 1887 showed it to be quite freshand pure except for a trace of ferric oxide, t o which it owes itsred colour. Theformula deduced from the analysis of this materialis Hl,Ca,Na24A1,2Si,4C60119. Other specimens examined proved tobe impure, chiefly owing to the presence of secondary natrolite.Cancrinite is analogous in constitution to nepheline and sodalite ;on alteration i t passes to an end-product consisting mainly ofnatrolite.91Clintonite Group.-An elaborate investigation of this group isdue to E.Manas~e,~2 who has analysed with great care three differentspecimens of ottrelite from three localities in the Apuan Alps(analyses 1-111 below), as well as five other varieties, includingmasonite (IV), sismondine (V), ottrelite from Ottr6 in the Ardennes(VI), ottrelite from Mont Fenouillet (VII), and Venasquite (VIII).An equally careful analysis (IX) of a variety called salmite hasbeen made by R. de Rauw.93 The specimen came from near Ottr6,where it occurs in tables of a dark greenish-yellow colour. Itscleavages are better, and its pleochroism less intense, than those ofchloritoid, and it contains almost twice as much manganese as theoriginal salmite from Vielsalm :88 0.Hauser and H. Herzfeld, Centr. Min., 1910, 756 ; A . , ii, 46.m A. Lacroix, Bull. SOC. franq. Mi%., 1910, 33, 321 ; A . , ii, 295.G. Pellini and E. Quercigh, Atti R. Accad. Lincei, 1910, [v], 19, ii, 445 ; A.,ii, 45.y1 S. J. Thugutt, Jakrb. Min., 1911, i, 25 ; A., ii, 298.92 Atti SOC. Toscana Sci. Nut. Memorie, 1910, 26, 121, and ibid., Proc. Verb.w An?&. SOC. Gkol. Belyique, 1911, 38, 209 B.1911, 20, 29256 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.1.11.111.I V.V.VI.VII.VIII.IX.SiO,. .A120:3. Fe,c),. FeO MnO.24'37 37'03 5-36 21-91 0'5226'07 37'01 3-97 24.76 tr.25'36 38'99 2'54 23'06 tr.24-56 34.57 5'93 27-20 1'1425'36 42'58 0.72 18-02 0-5342-93 29-60 0.86 15-43 3-7530'02 34TO 4-76 20.54 1-4237.87 31.12 3'25 20.48 0'6225.50 33.57 2'01 9-16 16-631-111 and V I I show traces of TiO,.CaO.MgO. H,O.0'16 4.32 7-160'12 1.90 7 030'24 3-16 7-28- 0.36 6-640'18 5-96 7-50 - 2.12 5'481.17 1-71 6.71tr. 1'44 5.800'91 4.40 6'96Total. S p gr.100 s 3 3'44100'86 3-51100-63 3-56100'40 3-54100'85 3'45100.17 3-25101'03 3-80100'55 3'4099.79 -IX contains also 0.65 P,O,.The ratios deduced from the first five analyses lead accurately tothe formula HZFeAlzSi0,. A similar result is obtained if it beassumed that the excess of silica shown in analyses VI-VIII is dueto admixed quartz, an assumption amply justified by microscopicalexamination. I n the case of salmite (IX), after deducting fromthe silica 2-12 per cent. present as quartz, the ratios are:SiO, : A1,0, : FeO : H,O = 1 : 0.8775 : 1-25 : 0.9875.This divergence from the type is possibly due to part of themanganese being present as Mn,O,.Corundum.-The colour of the oriental sapphire has been imitatedin the artificial product by adding small quantities of ferric andtitanic oxides to the alumina used.It has now been shown thatsmall quantities of titanium (0*03-0*058 per cent. of TiO,) are alsopresent in natural sapphires, and it is therefore concluded that thecolour of the gem is due to titanium present as an oxide or asa titanate of iron.94CuprodescZoieite.-A specimen from the Old Yuma mine, Arizona,contained 11.64 per cent. CuO, and agreed with the ordinaryformula R,(V04),,R( OH),, which also expresses the composition ofsmall, black crystals of descloizite from Argenti11a.~5Dolomite.-A crystalline, ferriferous dolomite of the formula3CaC0,,2~~g~Os,FeC0, has been found in the Simplon Tunnel.gGBgZestonite.-The oxychloride of mercury, Hg,Cl,O, found origin-ally a t Terlingua, Texas, also occurs in minute cubic crystals in asiliceous matrix in serpentine in San Mateo Co., California.Ananalysis made on 0.025 gram was in agreement with the acceptedf ormula.97EmpZcctl:te.-A specimen of this mineral was found to have theformula CUB~S,.~~Eu-zenitc.--Crystal fragments from the pegmatite of Satersdal,g4 A. Perneuil, Compt. r e ~ d . , 1910, 151, 1063 ; A . , ii, 4.7.y6 F. N. Guild, Zcitsch. Kryst. Min,., 1911, 49, 321 ; A . , ii, 902.96 G. Lincio, Atti R.Accad. Xci. Torino, 1911, 46, 969 ; A . , ii, 1101.y7 A. F. Rogers, Amer. J. Sci., 1911, [iv], 32, 48 ; A . , ii, 807.9s E. Priwoznik, Osterr. Zeitsch. Berg. Hutte?iu>esen, 1910, 58, 713 ; A., ii, 991.MINERALOGICAL CHEMISTRY. 257south Norway, have been carefully examined by H. L a ~ ~ g e . ~ ~ Hisresixlts tcre very similar to those obtained by Rammelsberg forp l y c r u s e from Hittero, and support Broegger’s view that euxeniteand polymase are the end-members of a series, in which the ratioMZOj :TiO, varies between the limits 1 : 2 and 1 : 6. Full detailsof the analyticai methods employed are given in this paper, togetherwith a discussion of the method of separating tantalic, niobic, andtitanic acids by means of ammonium salicylate.A specimen ofthe same mineral from Ambolotara, Madagascar, had a compositionclosely resembling that of the material from Arendal and fromEydland.1Fa;yulite.-A complete crystallographic and optical examinationof the small, orthorhombic crystals from the Cuddia Mida craterin the island of Pantelleria, has been made by J. Soellner.2 Thecomposition may be expressed by the formula Mg2Si0,,10Fe2Si0,,portions of the magnesium, iron, and silicon being replaced bycalcium, manganese, and titanium respectively. The relationsbetween the optical constants and the percentage of ferrous ironare in harmony with the results of Yenfield and Forbes.3 The axialratios and refractive indices are as follows:a = 1.8044, fi = 1.8383, y = 1.8462 ; 2V = 51° (yellow Hg light).Theoptic axial plane is 001. The acute negative bisectrix is perpendi-cular to 010.Pelspar. Group.-Analyses of two potash-felspars and of eightplagioclases ranging from Ab,.,An to Ab,.lAn have been given byI. Nordenskjold4 in the course of a general account of the mineralsfound in the pegmatite of Ytterby, Sweden. A labradorite of thecomposition Ab,An,.,,, from Yinacate, Sonora, Mexico, has beenexamined by Y. S. Bonilla~,~ and may be compared with themineral described by Ford and Bradley from the Altai Mountains.6A microperthite from the Ilmen Mountains and an oligoclase-albitefrom the south Urals have been described by W. W. Arschinow.7The former can be obtained in transparent pieces, which lend them-selves to optical examination; i t contains barium, and may be repre-sented by the formula Or,9Ab4,,Ce,. The latter is approximately(L : 5 : c = 0.4600 : 1 : 0.5811 ;Ab80An20.Zeitsch. Nuturwiss.FTalZe, 1910, 82, 1 ; A . , ii, 499.A. Lacroix, Bull. Soc. franq. Min., 1910, 33, 321 ; A., ii, 295.Zeitsch. Kryst. Nin., 1911, 49, 138 ; A . , ii, 502.A . , 1896, ii, 373.BUZZ. Geol. Imt. Unia. Upsalu, 1910, 9, 183; A., ii, 296.Parergones Inst. Geol. Mexico, 1910, 3, 427.Ann. Zeport, 1910, 244.Piiblication of the Petrographical Institute, Lithopca, Moscow, 191 I, 12 pp.REP.-VOL. VIII 258 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.As the result of an examination of a large number of felspars,Barbier found that orthoclases always contain small quantities oflithium and sometimes of rubidium, but that these elements do notoccur in microcline.8 These conclusions have been contested byW.I. Vernadsky and Mlle. E. Revutsky,Q but in a criticism of theirwork Barbier maintains his position,lO and still regards the presenceor absence of lithium as constituting a fundamental differencebetween the species.Garnet Group.-Analyses have been published of ipecimens ofandradite from Assynt., Sutherlandshire,ll from Sardinia,lZ and fromBerks County, Pennsylvania.l3 The first is a dark brown melaniteof rhombic dodecahedra1 habit, and contains 6-74 per cent. ofTiO,; the second is a honey-yellow garnet, and agrees very closelywith the formula Ca,Fe,(SiO,),, part of the iron being replaced byaluminium; the third is very similar to the second.Glazc6erite.-Brick-red nodules from Varang&lle, near Nancy,have a composition agreeing with the usual formula,Na,S0,,CaS04.14GZmcodote.-If hea-ted in a vacuum this mineral loses a littlesulphur and arsenic; if roasted and again heated, more sulphurand arsenic are obtained, until finally 4.38 per cent.of the sulphurand 23-37 per cent. of the arsenic contained in the mineral arefound in the distillate.15 The effect of roasting is apparently toproduce some disulphide, which on heating decomposes into mono-sulphide and sulphur. These experiments support the view thatglaucodote has the formulaSOASS*AsFe< I >co.Goldschinidtit e.-The individuality of this mineral has beendisputed by Palache, who on crysta.llographic grounds regarded itas identical with sylvanite.It appears, however, that its compositionis approximately represented by the formula (Au,Ag)zTe5, and i tmay therefore be properly regarded as a separate species.16Herderite.-A crystallographic examination of the material fromMt. Apatite, Auburn, Maine, has shown that the substance crystal-Ann. Mcport, 1909, 211.Compt. rcnd., 1910, 152, 1372 ; A . , ii, 122.lo BUZZ SOC. fmnq. Min., 1911, 34, 117 ; A., ii, 735.l1 A. Gemmell, Tmns. Edijtburyh Ggol. SOC., 1910, 9, 417 ; A!., ii, 300.l2 A. Serra, B m d . Accnd. Sci. Fis. Mut. Napoh, 1910, [iii], 16, 222; A . , ii, 123.E. F. Smith, Proc. Acnd. S a t . Sci. PhiZndeZphicc, 1911, 62, 538 : A . , ii, 501.V. Dlirrfeld, Mitt. geol. Lundesanstalt E2sass-Lolluingen, 1911, 7, 345 ; A., ii,295.'' A. Bcntell, Centr. Min., 1911, 411 ; A . , ii, 728.16: c. Gastsldi, Bend. Accnd. Sci. Pis. Meet. Nnpoli, 1911, @a], 17, 22 ; kf., ii, 901MINERALOGICAL CHEMISTRY. 259lises in the monoclinic system, two crystals being commonly twinnedtogether to form a, pseudorhoinbic individual. A partial analysisproved that the substance was a hydrofluorherderite,but as the angles approach nearer to those given by Penfield forhydroherderite than to those given by Dana for the hydrofluor-herderite from Stoneham, it is considered probable that Penfield'sangles hold for all varieties of the mineral.17HowZite.-Nodular masses of this remarkable calcium silico-borateoccur a t Lang, Los Angeles Co., California.18 The composition maybe represented by the formula C?~B,0,,B(OH),,H2Si0,.~yPersthen,e.-Specimens found in andesite rocks on the bordersof Transylvania aiid Bukovina have been studied by V.C. Butu-reanu.19 The crystals, which have the ratiosa : b : c=0.97 : 1 :0*57,are often twinned.on black, green, and greenish-grey crystals rmpectively :CaI[G(F,OH)]PO,,The three following analyses 1-111 were madeSiO, A1,0,. Fe(Mn)O. CaO. MgO. H,O. Total.I. 49'43 3'10 14'75 4'17 27.00 1.66 100'1111. 49 80 1.40 12.00 10.25 26.00 0.84 100 39111. 50'15 2.02 10.24 8.00 28.85 0.95 10021Jamesonite.-W. T. Schaller 20 is of opinion that the best analysesof this mineral are more in harmony with the formula4PbS,FeS,3Sb2S3,proposed by Loczka, than with the more complicated formula,7( Pb$, Fe+)S,4Sb2S3, adopted by Spencer.The mineral warrenite,held by Spencer t o be identical with jamesonite, is shown to be amixture of jumesonite and zinkemite, PbS,Sb,S,.EuoZinite.-In the course of a study of the heating curve of thismineral, Mellor and Holdcroft 21 have shown that an endothermicreaction occurs about 500O. This may be interpreted as indicatingthe decomposition of the kaolinite into silica, alumina, and water.A t 800° an exothermic reaction takes place, due to a change in thephysical condition of the alumina. They regard kaolinite as analuminodisilicic acid, (Ho)2>A12<E:EiZ>0, and point out thatother silicates may be referred to similar acids. The composition( W 2of a specimen from Northumberland,22 occurring in silvery-white17 TY.E. Ford, Amer. J. Sci., 1911, [iv], 32, 283 ; A . , ii, 1102.18 A. S. Eakle, Bull. Dept. Geol. Univ. California, 1911, 6, 179 ; A . , ii, 901.l9 AWL. Sci. Univ. Ja~sy, 1910, 6, 287.21 J. W. Rlellor and A. D. Holdcroft, Trans. Eng. Ceramic SOC., 1911, 10, 94 ;22 It. C. Burton, Proc. Univ. Durham Phil. Soc.. 1911, 4, 24 ; A . , ii, 735.Zeitsch. Kryst. 'Win., 1911, 48, 562 ; A . , ii, 209.A . , ii, 607.s 260 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.scales, showing a basal cleavage and a biaxial interference figure,agreed very closely with the formula A1,0,,2Si0,,2II2O.Marcasite.-The question as to the state of oxidation of the ironin this mineral has often been discussed. Recent experiments, inwhich the substance has been heated in a sealed tube a t 250° withcarbon tetrachloride or fused with bismuth chloride in an atmo-sphere of carbon dioxide, indicate that the iron is all present in theferrous state.23MispickeZ.-An attempt has been made to elucidate the constitu-tion of this mineral by studying its behaviour when heated in avacuum (compare glaucodote, p.258 above). In these circumstancessmall quantities of sulphur and of arsenic sulphide distil over,together with arsenic amounting to 12.2 per cent. of the substancetaken. The whole of the arsenic is not expelled, even if the heatingbe continued for a long time, but both the arsenic and sulphurcan readily be driven off if the substance is first roasted andthen distilled in a vacuum.The conclusion is drawn that theformula is Fe2As2S2, and the constitution analogous to that ofglaucodot e.24NepheZine.-In the case of natural minerals i t is often impossibleto deduce satisfactory formulce from the results of analysw carriedout with all care on apparently pure and homogeneous material.The suggestion has therefore been made that in such cases we aredealing with homogeneous mixtures of different compounds, someother constituent being preselnt in solid solution in the mineral.25This theory has been applied to explain the divergence of nephelinefrom the simple formula NaAlSiO,. Carefully selected materialfrom Eikaholmen, Norway, gave the ratios :SiO, : Al,O, : Na20 = 2.23 : 1.00 : 0.98.The analyses published by Morozewicz yielded similar results, theratio Si0,:A120, varying from 2-11 to 2.21.It is therefore con-cluded that the excess of silica is present in solid solution.Another view of the constitution of this substance has beenpropounded by W. T. Schaller,26 who regards it as a mixture of thefour isomorphous molecules, NaAlSiO,, KAlSiO,, CaA12Si20,,NaAlSi,O,, just as the plagioclase felspars are mixtures of themolecules NaAlSi,O, (albite), CaA12Si20, (anorthite), NaAlSiO,(#carnegieite), and KAlSi,O, (microcline).Olivine Group.- The data correlating optical properties andchemical composition in this group have been brought together by23 G. W. IJlummer, J. Amer. C'hem. Soc., 1911, 33, 1487; A . , ii, 901.24 A. Beutell, Centr. Min., 1911, 316 ; A., ii, 485.25 H.W. Foote and W. M. Bradley, Amer. J. Sci., 1911, [iv], 31, 25 ; A . , ii, 122.26 J. Washington Acnd. Sci., 1911, 1, 109 ; A . , ii, 992MINERALOGICAL CHEMISTRY. 261H. Backlund,27 who has also made numerous determinations ofrefractive indices and several new analyses. An abstract of thismemoir, which appeared originally in Russian, is now available forEnglish readers.0rthite.-Irregular masses of this mineral found in a felsparquarry a t Impilaks, on Lake Ladoga, were found on analysis tQcontain up to 1 per cent. of scandium oxide.28 Wiikite, anothermineral containing appreciable quantities of scandium, occurs a t thesame locality.Parisite.-A considerable addition to our knowledge of this rareflu-carbonate of cerium, lanthanum, and didymium has been madeby the study of the small, yellow crystals of rhombohedra1 habitfound in pegmatite a t Quincy, Massachusetts.29 The refractiveindices, o = 1.676 and E = 1-757, are considerably higher than thosepreviously accepted.The composition may be expressed by theformula (R/”F),Ca(C?O,),, where R”/ = Ce,La;,Di, and it is suggestedthat synchysite from Greenland is probably a variety of this mineralcontaining admixed calcite.Pearcede.-The formula S(Ag,Cu),S,As,S, was assigned to thismineral by Penfield in 1896, and it wm regarded by him as thearsenic analogue of polybasite, 9Ag2S,Sb2S,. The results of a carefulanalysis30 of black, platy crystals from the Veta Rica Mine,Coahuila, Mexico, agree, however, very closely with the formula8(Ag,Cu),,S,As,S,, and i t would appear also that the publishedanalyses of polybasite agree better with a formula of this type thanwith that which has hitherto been generally accepted.31Two analyses of the latter mineral recently made by H.Unge-mach32 on material from Las Chiapas, Sonora, and from Sonora,Mexico, respectively, are in harmony with this conclusion.Phosphorite Group.-A study of the published analyses of collo-phartite, dahllite (= podolite), and francolite (= staffelite) has ledW. T. Schaller to the conclusion that the following formulz arethe most probable 33 :Dahllitc.. ......................... 9Ca0,SP20,,Cn0, CO,, H,OFrancolite ........ %.. ............. 9Ca0, 3P20,,CaF2, CO,, H,OCollophanite ..................9Ca0,3P,05, Ca0,C02, H20 f nH20.Platinum.-The geological conditions under which this metal27 Trav. Must?e Gid. Pierre le grand Acad. Sci. St. Pilersbourg, 1909, 3, 77 ; A.,28 R. J. Meyer, Sitzunysber. K. Akad. Wiss. Bcrlin, 1911, 379 ; A . , ii, 406.29 C. Palxche and C. H. Warren, Am,er. J. Sci., 1911, [iv], 31, 533 ; A . , ii, 614.3 o F. R. van Horn and C. W. Cook, ibid., 518; A., ii, 614.31 F. R. van Horn, ibid., 32, 40 ; A., ii, 807.32 Bull. Soc. frang. Min., 1910, 33, 375; A., ii, 614.33 J. Washington Acad. Sci., 1911, 1, 151 ; A,, ii, 1102.ii, 616262 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.occurs in the Urals have been examined by L. Duparc,34 and fifteenanalyses of native platinum collected from stream beds in variouslocalities in that district have been made by H.C. Holtz.35PZum6ojarosite.-This rare mineral has been found lately in someabundance a t several localities in Beaver County, Utah.% It isdark brown in colour, and micaceous in structure. Under themicroscope the crystals are seen to be thin, uniaxial, hexagonalplates, optically negative, and strongly birefringent. Analysis gaveresults agreeing well with those previously obtained and in harmonywith the formula Pb0,3Fe20,,4S0,,6H,0.PoweZZite.-White plates analysed by S. D. Kusnetzoff 37 gaveresults agreeing closely with the formula CaMoO,. They thus differconsiderably from the Idaho specimens, in which part of themolybdenum is replaced by tungsten.Pyrites.-An elaborate study of the figures produced by etchingpolished faces of crystals of iron pyrites has been made by V.Posch1,M and he has also measured the hardness of the mineral indifferent directions.As the result of these experiments he concludesthat the crystals probably belong to the tetrahedraLpentagona1-dodecahedra1 sub-class of the cubic system. In the course of theinvestigation specimens from Elba, from Huttenberg, Carinthia,and from Seegraben in Styria were analysed. The composition ofthe specifically lightest and heaviest crystals from each locality wasdetermined, but although the density varied by as much as 0.05, noessential difference in composition could be detected. All the speci-mens contained arsenic, ranging from 0.78 to 1.73 per cent., andcopper from 0.04 to 0.63 per cent.I n order t o obtain information as to the state of oxidation ofthe iron in this mineral, G.W. Plummer has heated it to 250° withcarbon tetrachloride in a sealed tubs. Under these conditions75 per cent. of the iron is obtained in the ferrous state. He hasalso found that i t is readily decomposed by fusion with bismuthtrichloride in an atmosphere of carbon dioxide, all the iron remain-ing in the ferrous state. He therefore concludes that the whole ofthe iron is ferrous. This view is supported by the experiments ofL. Benedetk,sQ who has found that when heated to redness in anatmosphere of carbon dioxide, pyrites loses half its sulphur, ferroussulphide being left.Pyrurgyrite.4. Loczka 40 has analysed the crystals from34 Awh.Xci. phys. nut., 1911, [iv], 31, 211, 322, 439, 516 ; A., ii, 733.85 Tbid., and'also Tsch. Min. Mitt., 1910, 29, 498.3F 13. S. Butler and W. T. Schaller, Amcr. J. Sci., 1911, [iv], 32, 422.%7 Bull. Acad. Sci. St. Pt?tersbourg, 1911, 897; A . , ii, 1104.38 Zeitsch. Kyyst. Min., 1911, 48, 572 ; A., ii, 208.79 Zbid., 1910,'48, 447; A,. ii, 44. 40 Ann. Mus. H u g . , 1911, 9, 318MI N ERA LOG I C A L C H EM 1 S’I’R Y . 263NagybBnya, Hungary, which have been described by K. ZimSn~i.~lThe results are as follows:S. Ag. Cu. Fe. Sb. As. Total. Sp. gr.17.82 59-82 0.07 0’12 22-00 0.08 99’91 5.851Rieb eckite.-Long, black, prismatic crystals intergrown withaegirite occur in pegmatite in the Quincy granite of Massachusetts.42The cleavage angle is 55O5’.The optic axial plane is perpendicularto 010, and the acute negative bisectrix inclined 4-5O with thelong axis of the prism. Thecomposition of the specimen conforms t o the typebut only contains 42 per cent. of the first of these two molecules.It therefore resembles the specimens from New Hampshire andColorado rather than the original mineral from Socotra.Rhodizite.-In 1909 an analysis, by Pisani, of this rare substancefrom Madagascar was published by Lacroix.43 Two large crystalsfrom Ampakite, Madagascar, have recently been examined, and aportion of one of them has been found to have the compositionB,,Al,Gl,(Li,K,Crs,Rb,Na,H)4039, the percentages obtained differingconsiderably from those found by Pisani. The crystals are pseudo-cubic, being apparently rho;mbic dodecahedra, showing small facesof two complementary tetrahedra.44Rinmeite.-An analysis of carefully selected material fromHildesia confirms the formula FeCl2,3KCI,NaG1, given t o theoriginal mineral from Wolkramshausen.45 It can be prepared arti-ficially in rhombohedral crystals, and is to be regarded as a triplesalt, and not as an isomorphous mixture.An experimental investi-gation of the conditions under which iron salts occur in thePrussian potash-salt deposits has been carried out by H. E. Boeke,the discoverer of rinneite. He has studied the crystallisation ofsolut.ions of ferrous chloride and magnesium chloride, of ferrouschloride and potassium chloride, and of the three chlorides together,and deduced the equilibrium diagrams.46Schwartzemb erg&.-This substance has hitherto been regardedas an oxychloriodide of lead crystallising in the rhombohedralsystem. A recent investigation 47 of material from the San Rafaelmine, Sierra Gorda, Chili, has, however, shown that the crystals41 Am.Mzcs. Hung., 1911, 9, 251.42 C. Pnlache and C. H. Warren, Amer. J. Sci., 1911, [iv], 31, 533 ; A , , ii, 614.43 Ann. Report, 1909, 217.44 L. Duparc, M. Wuuder, and R. Sabot, B i d . floe. fran?. Min., 1911, 34, 132 ;The mineral is intensely pleochroic.N~Fe2Si4012,R4Si4012,A . , ii, 1105.F. Rinne and R. Kolb, Centr. Briin., 1911, 337 ; A., ii, 613.a. F. Herbert Smith and G . T. Prior, Min. Affig., 1911, 16, 77 ; A., ii, 1100.xi Jahrb. Min., 1911, i, 48 ; A., ii, 293264 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.are tetragolnal, and that the iodine is present, not as iodide, butas iodate.The analytical results are in agreement with the formula3 (P b Cl,, 2Pb 0) , P b ( 103)2,Stibiotuntdite.-In certain analyses of this mineral 48 tantalumand columbium were estimated by taking the specific gravity of themixed oxides on the assumption that this property is a linearfunction of the composition. Recent researches 49 show, however,that this is not quite the case, and a correction amounting to about2 per cent. must be applied to those analyses.Striiverite.-This interesting mineral, originally described byZambonini and Prior, from Craveggia, Piedmont, has recently beenfound in abundance in a pegmatite vein in the Black Hills of SouthDak0ta.5~ The small, black crystals resemble columbite in appear-ance, and are tetragonal, with angles near those of rutile.Themineral was completely decomposed on fusion with sodium hydrogensulphate, but owing to the difficulties attending the separation ofcolumbium, tantalum, and titanium somewhat different results wereobtained by different methods. The mean result approximates tothe formula Fe0,(Ta,Cb),0,,6Ti02. The mineral contains moretantalum than the original struverite, to which Prior gave theformula Fe0,(Ta,Cb),0,,4Ti02.Thuumasite.-This curious mineral, hitherto only recorded fromSweden and from New Jersey, has lately been observed in fissuresin metamorphosed dolomitic limestone in Beaver County, Utah.51The composition of the pure white material agrees with the acceptedformula, 3C'a0,Si02,,S0,,00,,15H20.Its specific gravity has theremarkably low value 1.84.Tikxsite.-In 1895 H. Sjiigren described a massive mineral ofthe composition (MgF)CaAs04. Pale green crystals of the sameformula have been found recently in manganese ore at Kajlidongri,Jhabua State, India, and have been subjected to a tborough exam-ination by G. F. Herbert Smith and G. T. Prior.b2 It would seemprobable that the curiously developed and often twinned crystalsbelong to that class of the monoclinic system which only exhibitssymmetry about a plane : a : b : c = 0.7503 : 1 : 0.8391 ; 0 = 5 9 O O g Theoptical characters agree with those determined by Sjogren, an acutenegative bisectrix emerging perpendicular to the good cleavage face101, the optic axial angle being large, 2V=82O44/, and the planeof the axes perpendicular to 010. The refractive indices area = 1.640, = 1.660, y = le6'i5(Na).D 3-77.-Ann. Aeport, 1906, 326.F. L. Hess and R. C. Wells, ibid., 31, 432 ; A . , ii, 499.49 W. E. Ford, Amer. J. Sci., 1911, [iv], 32, 287 ; A . , ii, 1104.51 B. S. Butler atid W. T. Schaller, ibid., 131 ; A . , ii, 209.gJ Min, ~Ifag., 1911, 16, 84 ; A., ii, 1103MlNERA LOGIC AL CHEMISTRY. 265Variscite.-W. T. Schaller53 has found that the bright green,orthorhombic crystals of this substance from Lucin, Utah, havethe usual formula, A1,0,,P20,,4H,0.Zeolite Group-A very large number of a(na1yses of members ofthis group have been published during the year.As none of themhas led to results of special novelty or importance, it will sufficehere t o refer to the work of E. F. Smith54 and F. A. Canfield.66Met eorites.Among the numerous investigations of these substances carriedout during the year, several of a general character claim attention.The first of these is the attempt made by 0. C. Farrington66 toapply to the stoney meteorites the system devised in America for theclassification of igneous rocks. With this object in view Farringtonhas made a critical compilation of the published analyses of thesemeteorites. In fitting them into the classification, certain modifica-tions of the latter become necessary, for regional names cannot beused for designating orders, sections, etc.A'ccordingly, a groupname is assigned to the sub-range only, the name chosen being thatof a meteorite which may be considered typical. Further, thepresence of uncombined metal in the meteorites necessitates theformation of several new sub-classes. Most of the meteorites falloutside the groups of terrestrial rocks, but Juvinose, Udenoae,Stawropdose, Bishopvillme, and Bustose among meteorites corre-spond respectively with Kedabdekase, Wehrlose, Argeinose, Mari-cose, and Websterose among igneous rocks. The minerals ofmeteorites are divided into two groups, salic and femic. The formerincludes quartz, leucite, felspar, and nepheline ; the latter pyroxene,olivine, magnetite, apatite, troilite, oldhamite, schreibersite, andnickel-iron.The methods of calculation employed and the mode ofinterpreting the analyses are fully set forth in Farrington'smemoir.The distribution of the elements in meteorites and the structureof these substances have been discussed by Wahl.67 He points outthat whereas many meteoric irons have been discovered long aftertheir fall, this is not the case with the stoney meteorites, whichare liable to escape detection altogether, unless their fall is actuallyobserved.If this is not kept in mind false estimates as to the relative53 J . Washington Acad. Sci., 1911, 1, 150; -4., ii, 1103.54 Proc. dcnd. Nut. Sci. Phil., 1911, 62. 538 ; A., ii, 501.55 Xchool M i n e s Quart. New York, 1911, 32, 215.57 W. A. Wahl, Zeitsch. anorg Chew&., 1910, 69, 52; A ., ii, 47.Field Museum of Natural Eistory. Publication 151, Geol. Series, 1911, 3, 195266 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.importance of iron in meteorites may easily be framed. The presenceof easily oxidisable minerals, such as nickel-iron, troilite, etc., andthe complete absence of those containing hydroxyl is especiallycharacteristic of meteorites; their magmas were in fact (( dry melts,”and may be compared with those of basic rocks. The only terrestrialirons which can be compared with meteoric irons are those fromDisco, and they contain more carbon and more oxygen than aremet with in any meteoric iron.Speaking generally, it may be said that meteorites and theircomponent minerals differ from terrestrial minerals and rocks incontaining a smaller amount of oxygen, and the meteorites them-selves may be classified according to their degree of oxidation.The presence of nickel in the metallic part of meteorites and itsabsence from the olivine is explained by the fact that the heatof formation of nickel oxide is lower than that of iron oxide.Whenall the available oxygen is exhausted, any calcium left unoxidisedunites with the sulphur present to form oldhamite, CaS. If thereis enough sulphur, iron sulphide is next formed. The sulphides ofcobalt and nickel are not met with, as their heats of formationare less than that of iron sulphide.These considerations combined with a study of the structure ofmeteorites leads to the conclusion that the meteorites are smallparts of larger bodies, and underwent various changes while stillbelonging to these larger bodies.The composition of these largerbodies was probably similar in all cases, the different varieties ofmet,eorit.es coming from different zones. The achondrites andsiderolites represent the solidified interior portions, and may becompared with the deep-seated igneous rocks. The chondrites comefrom the outer layers, and correspond to some extent with terrestrialeruptive rocks.Some experiments on the synthetical production of meteoric ironhave been made by Benedicks.68 He finds that alloys of iron with12 per cent. of nickel, prepa.red by the alumino-thermic process andcooled very slowly below 350°, have a structure which very closelyresembles that of the octahedral irons.On the other hand, Ovifakiron resembles a high-carbon steel, and contains free cementite andpearlite, a substance not found in meteoric iron.59 The atomicweight of the iron of a meteorite from Mexico has been determined,and the results found to agree exactly with those obtained by similarmethods for ordinary iron.6058 C. Benetlicks, Aletnllicrgie, 1911, 8, 85 ; A . , ii, 495.59 Ibid., 65 ; A . , ii, 287.6o G. P. Baxter and T. Thorvaldson, J. Amer. Chem. SOC., 1911, 33, 337 ; A , , ii,288MIFERALOQICAL CHEMISTRY. 267The composition of taenite has been discussed by 0. C. Farring-ton.61The question as to the origin of the curious glasses known asmoldavite, billitonite, etc., still continues to arouse much interest.On the one hand, their extra-terrestrial origin is maintained, andthey are classed together as a special group of meteorites under thename of tektites; on the other, they are regarded as obsidian orvolcanic glasses. Several contributions to our knowledge of theseobjects have been made recently. R. Beck 62 has analysed the gasesenclosed in tektites, and has compared them with those obtainedfrom obsidian. The former are distinguished by the presence ofconsiderable quantities of oxides of carbon and by the absence offree chlorine and hydrochloric acid. Certain small beads foundin prehistoric burial places in Bohemia have been found on analysisto consist of a highly basic glass.63 As an artificial origin for theseobjects seems highly improbable, and as their composition is quitedifferent to that of any known natural glass, i t is suggested thatthey probably belong to the class of tektites.One of the principal arguments relied on by the upholders ofthe meteoric theory is the peculiar character of the surface mark-ings of tektites. It would appear, however, that certain glassesfound in America exhibit very similar markings to those ofmoldavite and billit0nite.6~9 66 I n the light of these observationsthe case for the meteoric origin of the tektites becomes lessconvincing than it was.Among individual meteorites which have been examined latelywe may n d e the following :Dokhchi-In 1903 a number of meteoric stones fell in the neigh-bourhood of Dokiichi, Decca district of Bengal. The examinationof one of the smaller of these has shown it to consist of a finelygranular mixture of olivine and bronzite with irregular grains ofnickel-iron and traces of troilite. Analyses have been made of thenickel-iron and of the silicates attacked by hydrochloric acid, aswell as of the silicates undecomposed by that acid.@jEl Nakhla.-This meteorite fell recently near Alexandria, and issaid to consist largely of fragments of hypersthene.67 As severalanalysts have been a t work on it, further communications may beIt would appear to vary between Fe,Ni and FeNi.expected in the near future.Field Museum Nat. Hist. Pub. 145, Geol. Ser., 1910, 3, 165.62 Jfonntsbc?-. Dczctsch. Geol. Gs., 1910, 3, 240 ; A , , ii, 292.63 E. Weinsclienk and H. Stcinmetz, Centr. Jfin., 1911, 231 ; i l . , ijG. P. Merrill, Proc. United States Nat. M~~sczonz, 1911, 40, 481.‘jT, B. Jeiek and J. WoldEich, BtcEI. Intern. Acnd. Sci. Boh&me, 1920,H. E. Clarke and H. L. Bowmnii, Jfin. Mag., 1911, 16, 35 ; A.,S. Jleiiiier, Compt. rend., 1911, 153, 785 ; A., ii, 1106.501.15.i, 616268 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.Leighton.-A stone weighing 877 grams fell in 1907 nearLeighton, in Colbert Co., Alabama. It is a grey chondrite.Quinn Canyon.-A mass of iron weighing 1450 kilos. was foundin 1908 near the Quinn Canyon Mountains, Nye Co., Nevada. Itis a medium octahedrite, and contains 7-33 per cent. of nickel.0. C. Farrington,68 who has described the two meteorites lastmentioned, has also given a complete list of all the meteorites foundin the United States.A. HUTCHINSON.Field Nus. Nat. Hist., Pub. 145, Gcol. Ser., 1910, 3, 165 ; A., ii, 407