diluted, an excess of sodium carbonate added, and, while boiling, hydrogen peroxide is added drop by drop until the colour of the precipitated iron shows it to be in the ferric condition. The solution is filtered, and the precipitate washed with hot water. The precipitate is dissolved in the smallest possible amount of II sulphuric acid, an excess of sodium carbonate added, after which it is boiled, filtered, and washed. The combined filtrates and washwaters are acidified with sulphuric acid, and an excess of the acid added amounting to 2 to 5 cc. of the concentrated acid. Sulphur dioxide is passed in, and when the colour indicates that the vanadium is reduced the solution is boiled and a rapid current of carbon dioxide passed through the boiling solution to expel the last traces of the sulphur dioxide. The titration is made on the hot solution with permanganate of a strength not to exceed twentieth-normal. The iron precipitate can be dissolved, and the iron estimated in the usual way if desired. The volume at this point cannot conveniently be more than 75 cc. if the reduction with the spiral is to be carried on in one tube. If the ore is quite rich it is well to divide the solution here, and carry the reduction on in two test-tubes. The two solutions may be combined by pouring into the Erlenmeyer flask near the end of the titration, and the titration completed as if the reduction had been carried on in one tube. From this point on the procedure is the same as in the reduction of the mixtures of the pure salts described above. The number of cc. of standard permanganate used in the titration of the reduced solutions in the test-tube minus three times the number of cc. used in the titration after reduction with sulphur dioxide gives the number of cc. needed to re-oxidise the uranium alone from UO2 to UO3. Four samples of carnotite thus treated gave for uranium, 15'92, 15.66, 15:26, 15:46 per cent; for vanadium, 8:47, 8:57, 8:44, 8.44 per cent. Edgar used a Jones reductor filled with zinc in the differential reduction of iron and vanadium, and of molyb. denum and vanadium. In a number of experiments in this laboratory, where a zinc reductor was used for the reduction of the uranyl and vanadyl solutions, the results obtained were not so satisfactory as those obtained with the apparatus above described. If it be true that the uranium is reduced below the UO2 state, as Pullman and others suggest, then to pass it into a solution of ferric alum at once would give too high results, as far as uranium alone is concerned, but since some provision of this kind is necessary to prevent the re-oxidation of the highly reduced vanadium, it appears that an error is likely to occur in one direction or the other, whether the ferric alum be used or whether it be omitted. The method above described furnishes a convenient means of separating uranium and vanadium without the necessity of gravimetrically separating these two elements, and of determining each with a degree of accuracy fully equal to that which can be obtained by any of the methods heretofore published. — Journal of Industrial and Engineering Chemistry, i., No. 9. Royal Institution.-On Tuesday, January 18, at 3 o'clock, Prof. W. A. Herdman will commence a course of three lectures at the Royal Institution on "The Cultivation of the Sea"; on Thursday, January 20, the Rev. C. H. W. Johns delivers the first of two lectures on "Assyriology"; and on Saturday, January 22, Dr. H. Walford Davies begins a course of three lectures on "Music in Relation to other Arts" (with Musical Illustrations). The Friday Evening Discourse on January 21 will be delivered by Prof. Sir James Dewar on "Light Reactions at Low Temperatures" on January 28 by the Rev. Canon Beeching on "The Spiritual Teaching of Shakespeare"; and on February 4 by Prof. W. Bateson on "The Heredity of Sex." PROCEEDINGS OF SOCIETIES. - CHEMICAL SOCIETY. Ordinary Meeting, December 16th, 1909. Professor HAROLD B. DIXON, F.R.S., President, in the Chair. REFERRING to the loss sustained by the Society in the death of Dr. Ludwig Mond, the PRESIDENT stated that the Council had that afernoon passed the following resolution: "The Council of the Chemical Society desire to place on record their profound regret at the death of Dr. Ludwig Mond-a man distinguished no less for his life-long researches in pure and applied chemistry than for his wise beneficence for the advancement of Science. Dr. Mond was elected a Fellow of this Society in 1872, and served as a member of Council in 1885-6, and as Vice-President from 1887 to 1890, and again from 1894 to 1898. In the present year he was invited by the Council to accept nomination for the Presidency; unfortunately, ill-health prevented his acceptance. The industrial processes which Dr. Mond established and gradually perfected presented chemical and engineering problems only to be solved by a rare combination of scientific insight and of practical skill. The faith of Dr. Mond in well-guided research as the fertiliser at the root of a nation's industry was shown again and again when he applied his wealth to aid original investigation. Among his generous benefactions to the cause he had at heart, two stand out conspicuously-the fund which enabled the Royal Society to publish its catalogue of scientific papers, and the creation and endowment of the splendid Davy-Faraday Research Laboratory. To his adopted country Dr. Mond's work has been a help and an inspiration; we, his chemical colleagues, who know what that work was, desire to convey to his family our sense of the loss that science and the country have sustained." It was further announced by the PRESIDENT that in view of the completion of fifty years' Fellowship by the Past Presidents the Rt. Hon. Sir Henry Roscoe, Sir William Crookes, Dr. Hugo Müller, and Dr. A. Vernon Harcourt, it has been resolved by the Council that the Society hold a dinner some time at the end of May or beginning of June, 1910, and that these gentlemen be entertained as guests of the Society. Mr. Harold Baron was formally admitted a Fellow of the Society. Messrs. Percival Frederick Adams, 81, Rock Avenue, GilCertificates were read for the first time in favour of forth, Edinburgh; Arthur Ernest Everest, B.Sc., Clifton lingham; Alexander Charles Cumming, D.Sc., 39, ViewRoad, Gateshead-on-Tyne; Charles Wright Meanwell, House, Shrewsbury; Aquila Forster, B.Sc., 156, Coatsworth 15, Woodlands Crescent, Muswell Hill, N. Certificates have been authorised by the Council for presentation to ballot under By-law I. (3) in favour of Messrs. Tarak Nath Das, B.Sc., 31, Bhaironath, Benares City, India; John William McBeath, West End, Kimberley, S. Africa. : Of the following papers, those marked were read :*285. "The Production of Para-diazoimides from Alkyland Arylsulphonyl-para-diamines. A General Reaction." By GILBERT T. MORGAN and JOSEPH ALLEN PICKARD. Earlier experiments having shown that many arylsulphonyl-p-diamines yield arylsulphonyl-p-diazoimides on treating their diazonium salts with aqueous sodium acetate, a further selection of these acylated diamines containing very dissimilar alkyl- and aryl-sulphonyl groups has been examined, with the result that this condensation has been found to be a general one. Benzene-135 trisulphonyltri -p-phenylenediamineC6H3(SO2 NH·C6H4 NH2)3, was taken as a typical ex ample of a p-aminophenylamide derived from an aromatic | antimony have shown that, in the last case, the principal polysulphonic acid. When successively diazotised and treated with aqueous sodium acetate, it gives rise to the complex p-diazoimide, benzene-1: 3: 5-trisulphonyltri-pphenylenediazoimide, C6H3(SO2 N·C6H4°N2)3· As a type of a diamine containing a mixed aromatic alkylsulphonyl group, toluene-w-sulphonyl-p-phenylenediamine, C6H5 CH2 SO2 NH·C6H4 NH2, was prepared; it readily yields toluene - w - sulphonyl-p-phenylenediazoimide, C6H5 CH2 SO2 N·C6H4 N2. and methanedisulphonylbis-p-phenylenidiazoimide, CH2(SO2 N C6H4°N2)2, obtained respectively from methanesulphonyl-p-phenylenediamine, CH, SO2 NH·C6H4 NH2, and methanedisulphonylbis-p-phenylenediamine, CH2(SO2 NH C6H4 NH2)2. DISCUSSION. Dr. MORGAN, in reference to Prof. Armstrong's expression of opinion that the para-diazoimides were equilibrated mixtures, said that he should be inclined to regard this series, and also the closely allied para-diazo-oxides, as having alternately para-cyclic and para-quinonoid structures— were it not for the fact that these compounds closely resemble in physical and chemical properties the naphthylene-1: 8-diazoimides (III.) and 18-diazo-oxides (IV.) respectively. In the absence of evidence concerning the properties of peri- (1:8)-naphthaquinone or its derivatives, it seems preferable to regard these 1: 8-naphthylenediazoimides and diazo-oxides as being cyclic compounds with 6-membered rings (III. and IV.), and thence by analogy to accept Formula I. as representing the structure of the para-diazoimides. In answer to Dr. Hewitt's question as to the constitutio. of non-aromatic diazonium salts, he was of opinion that so long as one of the three phases of the diazonium oscillation could be formulated, the existence of the diazonium salt was possible, although such a compound with only one phase would be less stable than the aromatic diazoniun, salt with three phases. The dynamic hypothesis of the constitution of diazonium salts would be overthrown by the diazotisation of an amino-derivative of a fully saturated organic complex, but this result had never yet been realised experimentally. *286. "Organic Derivatives of Antimony. Part I. Tricamphorylstibine Chloride and Triphenylstibine Hydroxynitrate and Hydroxysulphate." By GILBERT T. MORGAN, FRANCES M. G. MICKLETHWAIT, and GEORGE STAFFORD WHITBY. Comparative experiments on the interaction of sodium camphor and the trichlorides of phosphorus, arsenic, and product is tricamphorylstibine chloride, (C10H150); SbCl2. (C6H5)3Sb(OH)·SO4 Sb(C6H5)3'OH, is similarly obtained by adding triphenylstibine chloride dissolved in alcohol to a hot aqueous solution of silver sulphate. *287. "The Constituents of Rumex Ecklonianus." By FRANK TUTIN and HUBERT WILLIAM BENTLEY CLEWER. Rumex Ecklonianus, Meisner, is a herb indigenous to South Africa, where it is reputed to possess medicinal properties. An alcoholic extract of this plant yielded, together with resinous products and a small amount of essential oil, the following compounds :-Ceryl alcohol; a phytosterol, C20H34O, apparently identical with rhamnol; palmitic, stearic, oleic, linolic, and isolinolenic acids; a small amount of ipuranol, C23H38O2(OH)2; kaempferol; chrysophanic acid; emodin; and emodin monomethyl ether; together with traces of other crystalline substances and large amounts of inorganic salts. A sugar which yielded d-phenylglucosazone was also present in small amount, but no evidence could be obtained of the presence of a glucoside. The emodin monomethyl ether which was isolated was identical with that obtained by Perkin and Hummel from Ventilago madraspatana (Trans., 1894, lxv., 932), and with that prepared synthetically by Jowett and Potter (Trans., 1903, lxxvii., 1330). The dimethyl ether of chrysyphanic acid was prepared, and obtained in yellow prisms, melting at 190°. *288. "The Influence of Non-electrolytes on the Solubility of Carbon Dioxide in Water." By FRANCIS LAWRY USHER. The solubility of carbon dioxide in solutions of the following substances was measured at 20°; sucrose, mannite, dextrose, glycine, pyrogallol, thiocarbamide, antipyrine, carbamide, acetic acid, catechol, urethane, n-propyl alcohol, acetamide, quinol, and resorcinol. The solutions were all N/2, with the exception of sucrose, which was examined at four different concentrations. It was found that the change in the solubility of carbon dioxide produced is a linear function of the quantity of sucrose present, for solutions more dilute than N/2, on the volumenormal basis of calculation. Of the fifteen substances enumerated above, the first twelve depress the solubility of carbon dioxide, the magnitude of the effect decreasing in the order given, from 26 per cent in the case of sucrose to I per cent in that of n-propyl alcohol. Acetamide, quinol, and resorcinol produce a slight elevation of solubility. The results were discussed from the standpoint of the theory recently advanced by Philip (Trans., 1907, xci., 711), which is found to be inadequate to account for the majority of the observations. Jahn's formula, C1/C2 = I, was also shown to be inapplicable to the data hitherto available. It is suggested, in common with Rothmund and others, that the phenomena observed can at present only be referred to mutual interaction of the molecules. DISCUSSION. Dr. PHILIP said that when he presented to the Society his communication dealing with this matter, he had expressed the view that too little attention had been paid to a- increases the influence of non-electrolytes on the solubility of gases. N The assumption made in his (Dr. Philip's) paper (loc. cit.), that the dissolved substance takes no part in the absorption of gas, should not be indefinitely extended. Obviously, there were many cases, for instance, the aqueous solution of acetic acid used by Mr. Usher, in which the dissolved substances had considerable solvent power for the gas. Mr. USHER replied that, as was expected, the equivalent depression of solubility was found to increase with dilution. The strongest argument against any explanation depending on the assumption that neither the dissolved substance nor the water which might be combined with it had no solvent action was, in his opinion, the observation that, with the majority of the substances examined, the solubility of carbon dioxide in the water of the solutions was in excess of its normal solubility in pure water. *289. "The Condensation of Benzaldehyde with Resorcinol." By FRANK GEORGE POPE and HUBERT HOWARD. Benzaldehyde and resorcinol in the presence of aqueous solutions of the alkali hydroxides condense to form 2: 4dihydroxybenzhydrol. The latter compound also condenses with phenols and with amines in the presence of zinc chloride to yield substituted xanthenes and hydroacridines, thus : OH Me The action of hydrogen dioxide on thiocarbamide and some of its derivatives in neutral and alkaline solution has been studied, and evidence was brought forward to show that under these conditions sulphinic acids are formed. 292. "Chlorination and Bromination of Acyanilides. Part II. The Action of the Halogen Acids on Chloro- and By Bromo-acylaminobenzenes." (Preliminary Note). KENNEDY JOSEPH PREVITE ORTON and WILLIAM JACOB JONES. In glacial acetic acid solution, hydrobromic acid, and acylchloroaminobenzenes and hydrochloric acid and acylbromoaminobenzenes react quantitatively, yielding identical solutions:-Ar NCIAC + HBr = Ar NHAC + BrCl and Ar NBrAc + HCl = Ar NHAC + BrCl (Brit. Assoc. Reports, Winnipeg, 1909). These solutions have been shown tintometrically and by aspiration (compare Orton and Jones, Trans., 1909, xcv., 1456) to contain bromine chloride, which has been found to exist nearly free from bromine and chlorine in this and other anhydrous solvents at 16°. In mixtures prepared by each of these ways, or from the anilide and bromine chloride, a rapid bromination of the anilide occurs, the speed of the reactions being the same In dilute acetic acids analogous reactions in each case. take place, but now differences appear, and complications are caused by the hydrolysis of the bromine chloride. Hydrobromic acid and an acylbromoamine react thus: -Ar NBrAc+ HBr=Ar·NHAC + Br2. The interaction has been shown by a tintometric method to be quantitative for glacial and dilute acetic acids. The mixtures are identical (except for the presence of hydrochloric acid) with those prepared from equivalent quantities of the corresponding chloroamine and two equivalents of hydrobromic acid: Ar·NCIAc+2HBr = Ar NHAC + Br2+ HCl. Moreover, the speed of bromination in these two mixtures is the same, and also equal to the speed of bromination in the system prepared from anilide and bromine. The velocity of bromination is now, however, very much smaller than in the systems above described, where bromine chloride is present. If an equilibrium exists between hydrobromic acid, the bromoamine, anilide, and bromine in acetic acid solution analogous to that found by the authors (loc. cit.) to exist between the chloroamine and hydrochloric acid, the bromoamine and hydrobromic acid are at very small concentration. In such solvents as chloroform and carbon tetrachloride, chloroamines and bromoamines cannot be shown to exist in detectable quantities in the presence of hydrogen chloride and bromide. The interaction of hydriodic acid and chloroamines in acetic acid solution has been investigated by a tintometric comparison with standard solutions of iodine chloride and iodine. When one molecular proportion of hydriodic acid is used, the reaction is quantitatively Ar NClAc+HI = ICI + Ar·NHAC; and with two molecular proportions of hydriodic acid, Ar NCIAc+2HI = Ar·NHAC + 12+ HCl. Although in aqueous solution, iodine chloride is hydrolysed, the repre-sulting hypoiodous acid then rapidly decomposing in the usual way, it possesses, even in 25 per cent acetic acid, considerable stability. 290. "Ethyl a Hydroxyisobutyrate. By WILLIAM PARRY. Ethyl a-hydroxyisobutyrate may be conveniently pared from pure acetone by converting the latter into its cyanohydrin, hydrolysing this, and isolating the resulting acid in the form of its zinc salt. Anhydrous zinc a-hydroxyisobutyrate (100 grms.) is then mixed with alcohol (200 cc.) and sulphuric acid (35 cc.), and heated on the water-bath for eight hours. After addition of water and extraction with ether, the solution is washed, dried, and the ether distilled. Fractionation of the residual liquid gives ethyl a-hydroxyisobutyrate, boiling at 145-150°. After distillation over phosphoric oxide, it boils at 148-150°, and the yield is about half the weight of acetone employed. The author is studying the action of Grignard's reagents on this ester and on others of similar type. 291. "The Action of Hydrogen Dioxide on amides." By EDWARD DE BARRY BARNETT. These results are in accord with the view suggested recently as to the process of conversion of chloro- or bromoamines into the isomeric chloro- or bromo-acylanilides (Orton and Jones, Proc. xxv., 233), namely, that primarily the former react with the halogen acids to form anilide and halogen, which can then interact, producing the C-halogen derivative. 293. "A Contribution to the Study of the Oxydases." By Ross AIKEN GORTNER. oxidising ferment, tyrosinase, obtained from the larva of The author has obtained a new variety of the tyrosine Tenebro molitor. This variety is distinguished from the Thiocarb-known tyrosinases by its insolubility in water, by its loss of vitality when treated with glycerol, or when subjected to drying, and by its inability to oxidise resorcinol, orcinol, | however, that argon has a dormant valency of I, and that quinol, or pyramidone. hydrogen has a dormant valency of 8 in addition to its normal valency of 1. A chromogen has been isolnted from the body contents of the larva of Tenebro molitor, which gives with tyrosinase colour reactions identical with those given by tyrosine. Tyrosinase has also been identified in two examples of myripods, Scalopocryptops and Julius canadensis (Newp.), in the larva of Cucujus clavipes, in the colourless plant Monotropa uniflora, and an observation has been made that extracts of almost all animal tissues possess the power of oxidising quinol. Leçons sur les Alliages Metalliques. ("Lessons on the Metallic Alloys"). By J. CAVALIER. Paris: Vuibert and Nony. 1909. THE great number of accounts of researches on alloys which have been published during the last twenty years are well summarised in this book, the author of which displays the characteristic lucidity and directness of writers of his nationality. The book deals both with the results of the fuller investigation of already known alloys and with the methods which have been adopted in the preparation of fresh products. It is divided into two parts: Part I. discusses the general methods of preparing and investigating alloys, and in Part II. the principles are applied to the special study of some important compounds. As far as possible the simplest and most easily understood alloys have been chosen as the subjects of the earlier chapters of Part II.; thus iron-carbon alloys and steels are considered last. Clear resumés of the essential points are made a special feature, the whole of Part I. being summarised in a concluding chapter, and the frequent crossreferences will be a great assistance to the student who wishes to make a thorough study of the book and is not satisfied with a cursory reading. Many illustrations of microphotographs are given, some of which have been reproduced from the Philosophical Transactions. CORRESPONDENCE. RE ATOMIC WEIGHTS AND VALENCIES. To the Editor of the Chemical News. SIR, I have found a further irregularity that appears to completely harmonise the figures of the series 1, 5, 1; 3, 2, 3, &c. (see CHEMICAL NEWS, vol. c., p. 281). Moreover, the sum of the valencies of each row, taking average or middle values (when these cannot be taken the highest valency is selected) divided by the number of elements per The "variable and is a constant-namely, 3. "single" valencies arranged in a series (periodic) may be expressed by connected geometric figures that are symmetrical. The values necessary to these two methods are in agreement, and coincide almost without exception with the carefully deduced valencies given by Dr. Friend in his book, "The Theory of Valency" (1909). It would appear, row Institute of Chemistry of Great Britain and Ireland. Examinations in Chemical Technology, April, 1910. -The Council will be prepared to arrange examinations in Chemical Technology to be held in April, 1910. The examinations will be open only to Fellows, and to those Associates who have been registered as such for at least one year, who produce evidence of practical technological training. Fellows and Associates who desire to present themselves are required to send in their applications not later than Wednesday, February 23rd, 1910. Literary Announcement. net, " - Messrs. Williams and Norgate will be publishing almost immediately at 12s. 6d. Y. Nikaido, B.Sc., M.A. Beet-sugar Making and its Chemical Control," by The aim of this work is to aid those starting their career in the beet-sugar manufacture, but who lack systematic training in the technique. Bearing this specially in mind, the author has endeavoured to explain not only the practical operations of sugar-house stations, but also the fundamental principles involved in the various processes of the sugar-house and in the methods for analysis of various sugar-house products. The volume is furnished with a large number of illustrations and specially prepared tables. MEETINGS FOR THE WEEK. WEDNESDAY, 12th.-Royal Society of Arts, 5. (Juvenile Lecture). "The Chemistry of Flame," by Prof. H. B. Dixon. THURSDAY, 13th.-Royal Society of Arts, 4.30. "Art Administration in India," by E. B. Havell. JUST PUBLISHED. 8vo. 78. 6d. net. (Inland postage 5d.). RECENT ADVANCES IN PHYSICAL AND INORGANIC CHEMISTRY. By A. W. Stewart, D.Sc., Lecturer on Organic Chemistry in the University of Belfast. With an Introduction by SIR WILLIAM RAMSAY, K.C.B., F.R.S. BY THE SAME AUTHOR. RECENT ADVANCES IN ORGANIC CHEMISTRY. With an Introduction by J. NORMAN COLLIE, Ph.D., LL.D., F.R.S., Professor of Organic Chemistry in University College, London. 8vo 78. 6d. net. (Inland postage 5d.). LONGMANS, GREEN, & CO., 39, PATERNOSTER ROW, LONDON. INSTRUCTION IN PURE CULTIVATION OF YEAST. Courses for Beginners, as well as for Advanced Students, in Physiology and Technology of Fermentations. Biological Analysis of Yeast. The Laboratory possesses a numerous collection of Yeasts (Brewers', Distillers', Wine, Disease Yeasts), Moulds, and Bacteria. Manuals: Alfred Jörgensen, "Micro-organisms and Fermentation" (London and New York, Macmillan & Co., 1900); and "The Practical Management of Pure Yeast" (London, "The Brewing Trade Review," 1903). The Laboratory supplies for direct use Pure Cultures of Yeast for Breweries, Distilleries, Wine Manufactories, &c., and performe Analyses of Yeasts, &c. Further particulars on application to the Director- THE CHEMICAL NEWS. VOL. CI., No. 2616. RESEARCHES ON THE QUANTITATIVE DETERMINATION OF THE ACID EARTHS.* By LUDWIG WEISS and MAX LANDECKER. III. SEPARATION OF NIOBIC AND TANTALIC ACID ACCORDING to Marignac, the separation of the two acids The best method up to the present was suggested by Marignac (Fourn. Prakt. Chem., cii., 448), and depended upon the different solubility of potassium titanium fluoride and potassium niobium oxychloride, but this method is too tedious, and not applicable to small quantities. (NOTE. -Quite recently one of us has obtained perfectly satisfactory separations of the three acid earths by fractional crystallisation of their potassium double fluoride from hydrochloric acid solution). Pisani (Fourn. Prakt. Chem., cii., 448) converted the acids into soluble fluorides, dissolved them in hydrochloric acid, reduced the solution with zinc, and titrated the reduced solution with potassium permanganate. As titanic acid is reduced first, the amount of titanium present in the niobic acid can be determined if the directions given by the author are followed. Marignac prepared a table for calculating the total amount of titanium present in a mixture of the acid earths, based upon the relations which obtain between the undissolved and soluble parts of the titanic acid; from the insoluble residue he calculated the total amount of titanic acid. Thus, while titanic acid alone on fusion with soda gives insoluble metatitanate, and niobic acid alone soluble niobate, even a small proportion of niobic acid is sufficient to keep a considerable amount of titanium (8 per cent) in solution. From this short historical review it will be seen that the present methods of separating titanium from niobium and tantalum are exceedingly unsatisfactory. We therefore paid special attention to this point. There is hardly an analogous case in analytical chemistry of an element affecting another in its reactions in the same way as niobium interferes with titanium. Tantalum does not mask the reactions of titanium so strongly as niobium. It might be expected that it would be very easy to separate elements which, in spite of great similarities, show so many very different reactions, but experience proves the contrary, as will be seen from the following experiments. A. Separation Experiments with Alkaline Melts. 1. Fusion with Sodium Carbonate.-We confirmed in many experiments the results of the investigations of Marignac and of Wöhler on the property of niobium of retaining a considerable amount (8 per cent) of the titanium in a state of solution in an aqueous extract of a soda melt. From this peculiar property of the two elements we concluded that some chemical compound of niobium and titanium must be formed during the fusion process; it must, however, be produced in small quantity only, as possibly a state of equilibrium results. The reasons for this are as follows: (a) A soda melt of niobic acid dissolves to a clear solution in hot water; a titanium melt with soda gives up no trace of titanium with hot water. If the clear niobate solution is added to the sodium metatitanate residue no trace of titanium goes into solution, not even on boiling. (b) An alkaline niobate solution remains clear when acidified with phosphoric acid; if a sulphuric acid pertitanate solution (obtained with hydrogen peroxide) is added to it, the niobic acid is precipitated, while the yellow precipitate solution is unchanged. But if a mixture of titanic and niobic acid is fused with soda, the melt is dissolved in phosphoric acid, and sulphuric acid + hydrogen peroxide are added, no trace of niobic acid is precipitated, not even on warming nor on standing for a day. We therefore thought that by adding an oxidising agent to the soda melt, we should prevent the formation of this niobium-titanium compound, and so we tried 2. Fusion with Soda and Saltpetre,-The soda is first fused, and then the mixture of the two oxides is added; it is taken up with evolution of carbon dioxide, and when the generation of gas has ceased some small crystals of saltpetre are added. After cooling, the melt is treated with hot water, the white precipitate is filtered off, and the filtrate is tested for dissolved titanium by sulphuric acid and hydrogen peroxide. It was then seen that the addition of saltpetre considerably reduced the amount of titanium which went into solution as compared with that dissolved by the soda melt Osborn (Ber., 1885, p. 721) determined titanium in pre-alone the filtrate showed only a very faint yellow coloration. sence of niobium colorimetrically. A. Knop (Ber., 1887, p. 1347) separated niobium and titanium as follows:-The mixture of acids or the finely powdered mineral was mixed with finely divided carbon made from starch, moistened with alcohol, introduced in a pasty state into a platinum boat, heated almost to a red heat, and while it was still hot a current of chlorine was led over it. Titanium and niobium chloride are formed, and can readily be separated from one another, for the former is much more volatile than the latter. Hall and Smith (C. B., 1905, p. 1161) unsuccessfully tried to find a method of separating titanic acid from the other acid earths; they could not improve upon Marignac's unsatisfactory results obtained by the fluoride method. * From the Zeitschrift für Anorganische Chemie, lxiv., 65. As this method of opening up the material was important for the subsequent experiments it must be described rather more fully. The soda is first fused in a platinum crucible until it forms a clear liquid, and the acids to be separated are then added. It is essential to cover the crucible immediately after the addition, and to remove the crucible from the blowpipe for some seconds, as otherwise some portions are ejected owing to the frothing of the melt. After the melt has subsided for some seconds it is again heated before the blowpipe, and it is best to arrange it so crucible lid red-hot, so that any of the melt adhering to it that the tip of the blowpipe flame makes the rim of the may be liquefied. An incomplete opening up may thus be avoided. To decompose o°3 to 0'4 grm. of acid it is sufficient if |