product unusually pure is essential, there exist therefore a great variety of exceedingly good and sharp methods for the separation and purification of thorium, and it must be understood that ionium, if present, and radio-thorium always remain unseparated from thorium in these processes as far as they have been examined." In the manufacture of thorium nitrate from monazite a large amount of residues of the cerium group of rare earths is obtained. Monazite contains 60 to 70 per cent of the cerium group or other rare earths besides thorium, and 3000 tons-which is the annual consumption of monazite-gives about 1000 tons of cerium and about 1200 tons of a mixture of the rare earths-lanthanum, neodymium, and praseodymium oxides. Considerable research work has been done in order to utilise these waste materials, and experiments have been made with almost every one of them. In order to obtain and separate the rare earth elements, thousands of crystallisations and fractionations are necessary, although cerium itself is separated with comparative ease. The untiring work carried on in the research laboratories of the industries, as well as by the scientists in both America and in Europe, will, no doubt, in time be crowned wi h successful technical applications of the by-products. SEPARATION OF MESOTHORIUM ON A COMMERCIAL Monazite sand is the main source of mesothorium, and contains also uranium and, consequently, radium. Mesothorium has properties similar to radium, and the radium therefore is separated together with the mesothorium. The methods employed in the extraction of mesothorium are well known, and have been described by Haitinger and Ulrich ("Bericht über die Bearbeitung der Pechblende Rückstände," Ber. K. Akad. Wis., 1908, cxvii., 619), and have been used in the extraction of radium (Moore and Kithill, "A Preliminary Report on Uranium, Radium, and Vanadium," Bull. 70, p. 79, Bureau of Mines, 1914). Some manufacturers of mesothorium add a small quantity of barium sulphate to the monazite sand during its treatment with sulphuric acid, whereby the mesothorium is separated with the insoluble material left after the treatment of the product with water. and after boiling the solutions. The content of mesothorium plus radium is found before the solution is boiled; after it has been boiled, the content of mesothorium alone is given, as the radium emanation is removed by boiling, and radium C1, which emits the y-rays, is, for all practical purposes, disintegrated after three hours' time. In regard to the method of measuring mesothorium and radium by the y-ray method, reference is made to the work of Ebler ("Chemiker Kalender " for 1914, ii., 371), and of MesoMeyer and Hess ("y-Strahlenmessung von thorpräparaten," Mitt. Inst. Radiumforschung, Vienna, July 2, 1914, p. 1443). The quantities of mesothorium that can be extracted from monazite are of course very small. One hundred metric tons of monazite, with a content of 5 per cent ThO2, contains approximately 4'3 tons of thorium metal. According to Rutherford ("Radio-active Substances and their Radiations," 1913, p. 552), one metric ton of thorium metal contains o'42 mgrm. of mesothorium. We have, therefore, 0'42 mgrm. of mesothorium per weight of 10-6 grms. of thorium, or 4°3 times 0'42 equals 1.8 mgrms. of mesothorium by weight. The activity due to mesothorium is three times as great as that due to radium when compared weight with weight. The mesothorium obtained from one ton of monazite therefore would be calculated as 5'4 mgrms. Lorenzen (private communication received from Julius Lorenzen, Tegel-Berlin, on "Chemical Manufacture of Mesothorium "), however, states that technically 25 mgrms. of mesothorium can be obtained from 1 metric ton of monazite, or 100 tons of monazite would yield 250 mgrms. of mesothorium. It seems, therefore, that technically a recovery of about 50 per cent is made. Mesothorium is sold on the basis of its activity compared with radium bromide of highest purity (determined by the y-ray method), and has been sold with increasing demand at 45 to 60 dols. per mgrm. The separation of mesothorium has been widely discussed in scientific and technical papers, and is outlined above. The manufacture of thorium nitrate from monazite is well known and has been described extensively. This manufacture, however, is briefly described above. The manufacture of the thorium nitrate is so highly developed that a recovery of go to 95 per cent of the thorium contained in the monazite has been made by many industrial concerns. The half-value period, or period of half life (the time required in which one-half of any given quantity of radioactive matter disintegrates - becomes transformed-is TABLE I.-Minerals contained in Monazite Sands, arranged called half-value perlod or period of half life) of mesothorium is 5'5 years, whereas that of radium is about two thousand years. The manufacture of mesothorium alone from monazite is not profitable, as the value of the mesothorium extracted would not pay for the cost of the monazite. As a by-product from thorium nitrate manufacture such manufacture should be of importance. QUANTITATIVE DETERMINATION of Mesothorium. The quantitative determination of mesɔthorium is carried on in the same manner as for radium (Soddy, "The Chemistry of the Radio-elements," 1911, p. 46; Rutherford, "Radio active Substances and their Radiations," 1913, p. 550). The content of mesothorium in preparations, all of which carry about 25 per cent of radium, is expressed in terms of the y ray activity of radium in equilibrium. For example, 5 mgrms. of mesothorium on this standard indicates that the y-ray activity of the mesothorium plus the radium contained in it one month after separation gives a y-ray activity equal to that of 5 mgrms. of pure radium bromide. If both the radium and the mesothorium are to be determined, then radium plus mesothorium is determined by means of the y-ray method, and afterwards, by the emanation method, the radium alone is determined. By the y-ray method alone can be determined the ratio of radium to mesothorium by measuring the y-rays before according to Specific Gravity. Mineral. Quartz Felspar Tourmaline Specific gravity. Letter showing relative quantitative occurrence.(a) Apatite.. Epidote.. Olivine Garnet .. b 4.8, 5'3 5'16,, 5'18 15, 19 d k Rutile Zircon (a) The order varies according to localities. Although in former years monazite and thorium nitrate were imported into this country, lately since the manufacture of mesothorium from the thorium residues has been begun-Europe prefers to export the ash of the broken incandescent mantles, which are high in ThO2, and keeps the monazite in order to obtain the mesothorium from the residues. The import duty on the ash brought into the United States is only 10 per cent ad valorem, whereas thorium nitrate pays 25 per cent duty. The thoria ash has been sold for 25 marks (6 dols.) per kilogrm. in and igniting the mixture that comes from the jet. With Europe. MINERALS IN MONAZITE Sands. The minerals contained in monazite sands, arranged according to their specific gravity, are shown in Table I. The conglomerate must be freed from the larger gravels and from the clays. Proper sizing is important before concentration; in sizing the remaining clay and mica particles should be removed by a sliming process. Four or five sizes should be made through sieves of 20, 50, 80, and 100 mesh. Such properly sized material, when treated on the large type of Wetherill electro-magnetic separator, having two magnets and 18-inch belt, gives the results shown in Table II. Tourmaline. per cent) and and rutile.. Current. First pole, first magnet; Second pole, first magnet; First and second pole of second magnet; distance, I to 5 ampères. 12 to 15 a small oxygen supply the characteristic " peachcoloured" flame is obtained. On increasing the pressure of oxygen a livid white central cone, surrounded by an outer sheath of pale "peach coloured" luminescence, is produced. As well as ordinary brass blowpipes, jets contrived of nickel and of silica were used. The oxy ammonia flame was allowed to play on a water surface or on ice. In all cases nitrate and nitrite were readily detected in oxide indicated. solution. In no case was the presence of hydrogen per and ammonia, that is so prominent in the presence of It would thus appear that the reaction between oxygen platinum and similar metals, occurs also to some extent when metals are entirely absent. It may be noted that some text-books (e.g., Roscoe and nitric acid is produced in the oxy-ammonia flame. No Schorlemmer, Shenstone, &c.) either state or imply that references to experiments are given, however, and seeing that, as far as the writer has been able to ascertain, Hodgkinson and Lownde's paper (loc. cit.) contains the only reference in the literature to the production of nitrates and nitrites in the flame, it would seem that the text-book statements rest solely on experiments with the oxy-ammonia flame in the presence of platinum. Chemical Laboratory, Gresham's School, Holt. ON THE SEPARATION OF CESIUM AND RUBIDIUM first pole, 6 mm. ; second (ampères. OF THE ALUMINIUM AND IRON ALUMS AND Platinum, &c. (if pole, 2 to 3 mm. any) (a) Residues oft belt were quartz, felspar, gold, zircon, rutile, &c. NOTE ON THE OXY. AMMONIA FLAME. ITS APPLICATION TO THE EXTRACTION SOURCES. By PHILIP E. BROWNING and S. R. SPENCER. ROBINSON and Hutchins (Am. Chem. Fourn., vi., 74) have recommended the crystallisation of the aluminium alums for the separation of cæsium and rubidium from potassium and lithium in lepidolite after the decomposition of that mineral by fluorspar and sulphuric acid. They have also called attention to the difference in solubility between the cæsium and the rubidium alums (see Note), and have sugelements. The marked difference in solubility between the potassium alum and the alums of cæsium and rubidium makes the method quite satisfactory for the separation of potassium from these rare alkalis, but the difference in solubility between the alums of cæsium and rubidium is not sufficiently great to bring about a rapid separation of these elements. THE fact that ammonia gas will interact with oxygen, producing a flame, has long been known. Thus Hofmann Ann., 1860, cxv., 285) describes a lecture experiment ingested fractional crystallisation for the separation of these which a stream of oxygen charged with ammonia is burnt at a jet. Hofmann's experiment was modified by Heintz (Ann., 1864, cxxx., 102), who introduced oxygen, saturated with ammonia by bubbling through a strong aqueous solu tion, into the interior of a Bunsen gas flame. On turning off the supply of coal-gas the ammonia continued to burn. Kraut (Ann., 1865, cxxxvi., 69; see also Ber., 1887, xx., 1113) made use of the catalytic effect of platinum and palladium to ignite a mixture of ammonia and oxygen. He succeeded in getting oxygen to burn beneath the surface of a strong ammonia solution. (NOTE.-100 parts of water at 15-17° C. will dissolve o 62 parts of cæsium alum, 2.3 parts of rubidium, and 13.5 parts of potassium alum). The work to be described was undertaken to obtain some definite information as to the value of the process of fractional crystallisation when applied to the problem of separating the alkalis. The process may be briefly described as follows: Lupton (CHEMICAL NEWS, 1878, xxxvii., 227) describes experiments very similar to Kraut's, and, like the latter, used a platinum spiral to ignite his oxy-ammonia mixtures. Hodgkinson and Lowndes (CHEMICAL NEWS, 1888, lviii., 27) used a platinum jet to introduce oxygen into a A solution obtained from the decomposition of lepidolite flask containing strong ammonia solution. The jet was by heating with fluorspar and sulphuric acid after the removal fixed about 1 cm. from the liquid surface, and the mixture of the calcium sulphate was evaporated until on standing issuing from the neck of the flask ignited, whereupon the the mixed alums crystallised out. The mother-liquor was oxygen burnt at the jet. They found that at certain pres- poured off into a second flask, and this liquid was evasures fumes of ammonium nitrite and nitrate were pro-porated until another crop of crystals was obtained, and duced, as might be expected from the fact of the platinum jet. The writer has found that an oxy-ammonia flame can readily be produced by leading ammonia and oxygen into the appropriate inlets of any ordinary blowpipe burner the new mother-liquor poured into a third flask, and so on. The crystals in the first flask were dissolved in a small amount of water by warming, and again allowed to crystallise, the supernatant liquid being poured into the second flask upon the crystals which had formed there; these crystals, in turn, were dissolved in this liquid, and allowed to recrystallise, and the process was continued through all the series of flasks. The crystals separating in flask number one were repeatedly dissolved in fresh water and allowed to recrystallise in this way, and the mother-liquor was kept moving along the series of flasks in succession. By this method the more insoluble alum was concentrated at the upper end of the series, while the more soluble alum moved toward the lower end. After six such crystallisations applied to a solution of the alkalis from lepidolite, the crystals in the first flask showed only cæsium and rubidium when examined before the spectroscope on a platinum wire, and the crystals in the sixth flask gave a decided test for potassium and a very strong test for lithium and showed only traces of cæs um and rubidium. A mixture of cæsium and rubidium alums obtained by the above process was subjected to this same crystal lisation method. After about seven crystallisations, the crystals in the first flask were found to be pure cæsium alum, but the crystals in the sixth flask, while strong in rubidium, still gave evidence of the presence of cæsium. The process of crystallisation was continued until 22 fractions had been obtained before the cæsium had been completely removed. The crystals in the twenty second flask proved to be pure rubidium alum, no evidence of the presence of cæsium being found. Locke (Am. Chem. Fourn., xxvi., 166), in studying the properties of the alums, has called attention to the differing solubilities of these interesting compounds, and notes in particular the great difference of solubility of the cæsium and rubidium and iron alums (see Note) as compared to that of the corresponding aluminium alums, and it has been suggested that this difference might be of analytical value. (NOTE.-100 parts of water at 25° C. dissolve 2.7 parts of ræstum alum and about 17 parts of rubidium alum). In order to investigate this point a mixture of cæsium and rubidium iron alums was prepared and subjected to the same process described above. After four crystallisations, the crystals in flask number one gave no test for rubidium, but showed abundance of cæsium, and after the process had been continued until 8 fractions were obtained, the eighth fraction was found to be free from cæsium and contained pure rubidium alum. A further experiment was made as follows:-Ten grms. of the mixed cæsium and rubidium alums from lepidolite were dissolved in water, and the aluminium hydroxide was precipitated by ammonium hydroxide and filtered off. The filtrate, evaporated to about 130 cc., was poured upon some crystals of ammonium ferric alum in quantity somewhat in excess of the amount necessary to allow the replacement of the ammonium by the cæsium and rubidium. The solution was then warmed until the crystals were dissolved. On cooling, crystals separated which, when examined, gave abundant evidence of cæsium but no test for rubidium. This experiment suggested a convenient method for the formation of cæsium alum, and also seemed to show that the more insoluble alums were readily thrown out of solution by treatment with strong solutions of the more soluble alums. This method was applied quite successfully to the extraction of cæsium from pollucite as follows: The mineral was decomposed by hydrochloric acid, and after evaporation and the removal of silica the acid extract was poured upon crystals of ammonium aluminium alum and warmed until the crystals had dissolved. On cooling. cæsium alum separated in abundance, and the mother-liquor, although not free from cæsium, after one treatment consisted mainly of ammonium chloride. After about two recrystallisations the crystals obtained in the first treatment were found to give no test for either am monium or chlorine and to be pure cæsium alum. The remainder of the cæsium was easily obtained by a few crystallisations of the mother-liquor. This method has advantages over the other methods for the extraction of cæsium from pollucite which involve the precipitation of the cæ ium as the double lead or antimony chloride, and the decomposition of these compositions by hydrogen sulphide or ammonium hydroxide. A few experiments were made to determine the insolu bility of the cæsium and rubidium in a saturated solution of ammonium aluminium alum. It was found that I cc. of a solution of RoC containing 0.0002 grm. Rb would give a perceptible precipitate when treated with 5 cc. of a saturated solution of ammonium alum, and that I cc. of a solution of CCl containing o 00005 grm. Cs would give a precipitate of cæsium alum. By the careful study of conditions and the use of the other alums it is hoped that these observations may lead to some advances in the analytical study of these elements, and we hope to give further attention to this problem.American Journal of Science, xlii., 279. FUEL ECONOMY.* Introduction. THE national aspects of fuel economy may be considered from two somewhat different standpoints, namely, (1) in view of the economic situation created by the war, which wil necessitate the general adoption of more scientific methods in the future development and utilisation of the nation's mineral reserves, and (2) in view of that remoter, but possibly not far distant, future when our available coal supplies will be restricted by approaching exhaus ion. In approaching its task the Committee decided that it could tion upon the mcre immediate aspect af the problem. best serve the national interest by concentrating its atten It can hardly be questioned that the chief material basis of the great industrial and commercial expansion of this country during the past century has been its abundant supplies of easily obtainable coal, which, until recent years, has given us a position of advantage over all other countries. It is also equally true that we can no longer claim any advantage in this respect over our two closest competitors. There can be little doubt but that up to the present we have been wasteful and improvident in regard to our methods of getting and utilising coal, and that not only are great economies in both these directions attainable, but also that the question of the general adoption of more scientific methods in regard to these matters is one of vital importance, in view of the trying period of economic recuperation which will immediately succeed the war. For some years before the war the average price of coal at the pit-head had been decidedly on the up-grade, owing chiefly to deeper workings, higher wages, and greater precautions for ensuring the safety of the mines. The result of the great coal strike of 1912, and the legislation which it provoked, was to accentuate this tendency. And if, as seems probable, prices continue to rise for some time after the war at an accelerated rate, as compared with the pre-war period, the question of the best utilisation of fuels will be of increasing importance to the nation. If anything ought to arouse public epir ion to the gravity of the situation, it is surely afforded by the statistics published in the Report upon the World's Coal Resources, issued by the International Geological Congress in the year 1913. According to this estimate, the geographical distribution of the world's total possible and probable reserves of coal of all kinds available within 6000 feet of the surface (amounting in all to 7,397.553 million metric tons) may be represented diagrammatically (Figs. 1 and 2). *First Report cí the Committee (Prof. W. A. Bone, Chairman Mr. E. D. Simon, Secretary). Read before the British Association (Section B, Newcastle Meeting, 1916. pound rate of 2 per cent only. During the period 1910-14 the United States produced nearly twice as much coal as Great Britain, and, assuming that these relative rates of increase are maintained after the war, it may be predicted that Germany's output of coal will overtake that of Great Britain about twenty years hence, when each country will be producing some 420,000,000 tons per annum. The public cannot be too often reminded that not only is coal of prime importance as a fuel, but also that, when suitably handled by the chemist, it yields very valuable by-products, which are the raw materials of important industries. Thus from coal-tar, and other by. products of its distillation, are obtained the raw materials for the manufacture of both synthetic dyes and drugs, and certain high explosives. Another important by-product obtainable is ammonia in the form of sulphate, which is chiefly used as a fertiliser in the production of foodstuffs. The use of artificial fertilisers, including ammonium sulphate, by agriculturists in Great Britain is still in its infancy, and the near future ought to see a large expansion in the home demands for nitrogenous fertilisers. that also in regard to the two prime considerations of | 4 per cent, whilst the British output was increasing at a comquality and cost of production the probably compares favourably with Great Britain and the Empire. Moreover, it may be pointed out that in the United States both the Government and the University of Illinois bave, for some years past, conducted numerous important chemical investigations and large-scale trials upon the character of the principal American coal seams and their adaptation for various economic ends, and that, in consequence, American manufacturers have at their disposal much more complete and systematic information about their country's coal resources than is at present possessed by their British competitors. Also, the United States Government, which is continually extending its policy of the conservation of its natural resources, has already taken legislative steps to prevent the premature exploittion of the coalfields of Alaska. Nor has Canada lagged behind her neighbour, as is proved by the recent exhaustive "Investigation of the Coals of Canada with Reference to their Econon ic Qualities," conducted at the McGill University, Montreal under the authority of the Dominion Government, and published in the years 1912 and 1913 by the Department of Mines in six imposing volumes. No such comprehensive investigations have ever been undertaken in this country, where they are much needed. The Committee is of opinion that the example of the United States and Canada might be followed with advantage to the industrial community by the Government of Great Britain, and that representations should be made with the object of inducing the Government to provide adequate funds in aid of further researches and investigations upon the chemical character of the principal British coal seams, the best means for their future development in the national interest, and upon problems of fuel economy, including the utilisation of all the by-products obtainable from coal. From these figures it would appear that, during the period in question, the world's demands have continuously increased at a compound interest rate of nearly 5 per cent per annum. Another important fact is that these demands have been principally met by three countries, namely, the United States, Great Britain, and Germany, which, between them, have hitherto annually raised 83 per cent of the total anthracite and bituminous coals consumed in the world. This being so, it is of interest to compare the relative rates of increase in the coal productions of these three countries during recent years, which may best be deduced from a comparison of quinquennial averages over a period of fifteen years, from 1900-1914 inclusive (Table I.). Among other products obtainable by the low-temperature distillation of coal are liquid hydrocarbons of the paraffin and naphthene series, and it is probable that large quantities of "motor spirit" could be manufactured in this country from coal. There is no doubt that we in this country have not been sufficiently alive to the importance of recovering such by-products from the raw coal raised in our mines, and that we have been very much behind Germany in this respect. Thus, for example, whilst in the coking industry modern by-product recovery plants had been universally installed years ago throughout Germany, we were, in 1913, still carbonising about six and a-half million tons of coal annually for metallurgical coke in oldfashioned bee hive ovens. Also, whereas our total production of ammonium sulphate from coal was in 1913 about 318,000 tons, Germany produced nearly half a million tons from a very much smaller output of coal. The community needs to be reminded that, at least so far as this country is concerned, progress in fuel economy involves something more than increased thermal efficiency in respect of power production and of heating operations generally, important as these undoubtedly are. It also involves the whole question of the better utilisation of our coal, including the recovery of by-products and the consequent abolition of the smoke nuisance, which at present, directly and indirectly, costs the country many millions of pounds per annum. There are two outstanding features in the bistory of the British coal trade to which the Committee desires to draw attention. One is the remarkably steady increase in the total output of our mines, which, since 1870, has been maintained at an almost uniform compound interest rate of 2 per cent per annum, as the table of quinquennial averages over a period of forty-five years - 1870 to 1914 — shows (Table II.). United States. 1870-74 121'5 121'5 112.5 1875-79 133.6 131'1 0'146 139.8 168.3 (a) Excluding lignites and brown coals. From these figures it may be inferred that up to the outbreak of the war the coal output of the United States was increasing annually at a compound interest rate of about 6 per cent, that of Germany at a componnd rate of about | 1910-14 1895 99 1900-04 1905-09 |