University of Birmingham.-Prof. P. F. Frankland, Ph.D., LL.D., F.R.S., Dean of the Faculty of Science, University of Birmingham, has retired after long service at that University. Appointment.-Dr. T. A. Henry, late Superintenden of the Laboratories at the Imperial Institute, London, has been appointed Director of the Wellcome Chemical Research Laboratories, London. Dr. F. L. Pyman, the former Director of these Laboratories, has accepted the Professorship of Technological Chemistry in the Manchester Municipal College of Technology, and in the University of Manchester. MEETINGS FOR THE WEEK. MCNDAY, March 3rd.-Royal Institution, 5. (General Meeting). TUESDAY, 4th.-Royal Institution, 3. "How Silk is Grown and Made-Mulberry Silk," by Prof. H. Maxwell Lefroy. Royal Society of Arts, 4 30. "Science and Industry in Canada," by Prof. J C. McLennan. WEDNESDAY, 5th.-Royal Society of Arts, 4.30. "The Rubber Indus try-Past and Present," by B. D. Porritt. THURSDAY, 6th.-Royal Institution, 3. "Rossetti," by Charles Aitken. Royal Society of Arts, 4.30. "The Need for a History of Bengal," by W. R. Gourlay. FRIDAY, 7th.-Royal Institution, 5.30 "The Hardening of Steel," by "Spectrum Analysis and its Application to Atomic Structure," by Prof. Sir J. J. Thomson, O.M. Analytical and Consulting Chemist, M.Sc., A.I.C. (Food and Drugs), will buy existing Practice or purchase Partnership with view to extension-Address, Box 135, W. H. Smith and Son Kingsway, London, W.C. 2. Analytical Chemist with considerable experience, just released from Government work, wishes for a Position with an established firm, and would also consider Partnership with same or with Chemist who has had previous experience in Private Practice Work with view to opening out.-Address, "Analytical," CHEMICAL NEWS Office, 16, Newcastle Street, Farringdon Street, London, E.C.4. Assistant Works Manager seeks progressive Position with Chemical Firm. Fully qualified Chemist. Twelve years' very varied Works experience. Good knowledge of Engineering. Accustomed to administration.-Address, A. W., CHEMICAL NEWS Office, 16, Newcastle Street, Farringdon Street, London, E.C. 4. Analytical Chemist (Junior Assistant) for Accumulator Works, London. Must be thoroughly used to Analyses of Lead, Lead Oxides, Acids, Waters, &c. Electrical knowledge an advantage. Salary to conimence £200 per annum.-Write age, experience to Box 69, at Horncastle's, 60, Cheapside, E.C. 2. Assistant Analyst (Woman), four years' ex perience in General Analytical Laboratory (Foods, Brewingsugars and Malts, Chemicals, &c.), desires London permanency. Matriculated with Chemistry. Salary £150.-Address, V. A. H., CHEMICAL NEWS Office, 16, Newcastle Street, Farringdon Street, London, E.C. 4. Demobilised Cadet (19) requires Situation in Laboratory. Good all-round education; Public School. Passed Inter. B.Sc. One year's previous experience.- Address, J. C. H., 23, Westcott Street, Hull. Lady Chemist, Graduate, wanted for Chemical Laboratory. Apply, Chief Inspector, West Riding Rivers Board, Wakefield, stating present salary. W Works Analytical Chemist required. One conversant with Soap Manufacture, Nicotine Extractions, and Agricultural and Horticultural Preparations. State full particulars and salary required.-Address, W. A, CHEMICAL NEWS Office,: 1 Newcastle Street, Farringdon Street, London, E.C. 4. Experienced Research Chemist and Analyst, with excellent Laboratory facilities in City, is now free to undertake RESEARCHES connected with the manufacture of CHEMICALS, INTERMEDIATES, DYES, &c.; also the Utilisation of WASTE PRODUCTS and all classes of ANALYSIS."Laboratory," 7, 8, & 9, Bolt Court, Fleet Street, London. CORPORATION OF GLASGOW. he Corporation invite applications for the The position of MANAGER for their CHEMICAL WORKS. Applicants must be fully qualified Chemists, able to deal fully with all HERIOT-WATT COLLEGE, EDINBURGH. Liquid Products from Gas Works, to advise as to the introduction of Principal-A. P. LAURIE, M.A., D.Sc. SPECIAL FIRST, SECOND, and THIRD YEAR INTENSIVE COURSES for Students demobilised from the Forces will commence on APRIL 15 next and continue till JULY 25, in the subjects of MECHANICAL ENGINEERING, These Courses will be suitable for Students desiring to refresh their knowledge, or who wish to qualify for the Diploma of the College, and will count as equivalent to one year of the usual Three Years' Course for the Diploma, either in the First, Second, or Third Years. Fee, 12 125.; Matriculation Fee, ss. APPLIED CHEMISTRY. Similar Courses in Applied Chemistry can also be obtained. The attention of Demobilised Students is directed to the arrangements made by the Government for Payment of Fees and Maintenance of approved applicants. Students desiring to enrol must apply, stating full particulars as to their pre-war University or Technical College training to the Interim Principal, all necessary up-to-date plant for the working-up of the By-products, and be competent to supervise the erection thereof. Applications, stating salary required, age, qualifications, training, and experience, to be endorsed on the outside "Gas DepartmentChemist" and lodged with the subscriber not later than WEDNESDAY, 5th proximo. J. LINDSAY, Town Clerk, City Chambers, Glasgow, Feb. 12, 1919. LINEN INDUSTRY RESEARCH Applications are invited for the Post of Association. DIRECTOR OF RESEARCH for the Linen Industry Research Candidates should state their Scientific and other qualifications, such as administrative, industrial, &c., and furnish the names of three references. The functions of the selected candidate will be to make a survey of the entire field of Research in the Linen Industry from the growing of the flax to the completion of the finished product, to draw up a programme of Research, to organise the scheme, and to supervise its carrying out. A salary of not less than £1000 a year is offered. Further particulars and the Prospectus of the Association may be obtained from the SECRETARY, 3, Bedford Street, Belfast. Property of Chemic, l'aboratory ♬ round College CHEMICAL NEWS AND JOURNAL OF PHYSICAL SCIENCE Proprietor and Editer, Sir Wm. Crookes, O.M., I F.R.S. [Established (WITH WHICH IS INCORPORATED THE "CHEMICAL GAZETTE "). in the Year 1859. Published Weekly. Annual Subscription, free by post 1 Entered at the New York Post Office as Second Class Mail Matter. Transmissible through the Post-United Kingdom, at Newspaper rate; Canada and Newfoundland, at Magazine rate. CAPPER PASS & SON, Lim., Assisted by L. WHINYATES, Assoc. M.S.T. An up-to-date compilation of Chemical, Physicochemical, Mineralogical, and Mathematical Tables, together with Technical Methods of Analysis. With New Sections by G. D. ELSDON, F.I.C., and A. D. HEYWOOD, on " Dairy Products." W. MATHER, Assoc. M.S.T., on "Tannin Materials." J. W. MELLOR, D.Sc., on "Analysis of Clays, &c." L. G. RADCLIFFE, M.Sc. Tech., F.I.C., on "Essential Oils." E. J. RUSSELL, D Sc., F.R.S., on "Agricultural Chemistry." COMPLETE REVISION OF DATA IN INORGANIC AND A. BOAKE, ROBERTS, & CO. (LIMITED), JOHN J. GRIFFIN & SONS, LTD., Stratford, London, E. KINGSWAY, LONDON, W.C CARBOLINEUM. OLD established firm in Holland, of pure Dutch origin-speciality, TAR PRODUCTS requires offers from British Chemical Works for the exclusive SAI E in Holland of CARBOLINEUM, CREOSOTE, and other similar WOOD PRESERVATIVES in considerable annual quantities. Applications, with full details, to "N. 7990," MAX R. NUNES, Advertising Agency, Amsterdam. No. 3 S.B. (Code word "Accent "). BEAM, 6 inches; CAPACITY, 500 grms. SENSITIVITY, 0.1 mgrm. Experienced Research Chemist and Analyst, with excellent Laboratory facilities in City, is now free to undertake RESEARCHES connected with the manufacture of CHEMICALS, INTERMEDIATES, DYES, &c.; also the Utilisation of WASTE PRODUCTS and all classes of ANALYSIS."Laboratory," 7, 8, & 9, Bolt Court, Fleet Street, London. HERIOT-WATT COLLEGE, EDINBURCH. Principal-A. P. LAURIE, M.A., D.Sc. SPECIAL FIRST, SECOND, and THIRD YEAR INTENSIVE COURSES for Students demobilised from the Forces will commence on APRIL 15 next and continue till JULY 25, in the subjects of MECHANICAL ENGINEERING, ELECTRICAL ENGINEERING, These Courses will be suitable for Students desiring to refresh their knowledge, or who wish to qualify for the Diploma of the College, and will count as equivalent to one year of the usual Three Years' Course for the Diploma, either in the First, Second, or Third Years. Fee, 12 12s.; Matriculation Fee, ss. Similar Courses in Applied Chemistry can also be obtained. The attention of Demobilised Students is directed to the arrangements made by the Government for Payment of Fees and Maintenance of approved applicants. Students desiring to enrol must apply, stating full particulars as to their pre-war University or Technical College training to the Interim Principal. NOTICES. EDITORIAL.-All Literary communications, and Books, Chemical Apparatus, &c., for review or notice to be addressed to the EDITOR. SUBSCRIPTIONS, per addressed PUBLISHER. L. OERTLING, TURNMILL STREET, Rined to the fu puts annum, payable in advance, should be LONDON E. C. 1. BACK NUMBERS and VOLUMES can be purchased on application to the MANAGER. If in good condition, Sixpence per copy will be ADVERTISEMENTS. All communications for the Advertisement paid for any of the undermentioned numbers of the CHEMICAL NEWS which may be forwarded to this office : Department to be addressed to the ADVERTISEMENT MANAGER. 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THE CHEMICAL NEWS, 10, Newcastle Street, Farringdon Street, NDON E.G CHEMICAL NEWS, March 7, 1919 Chemical Element and Radio-active Change. 109 intended to express any physical significance; but for the fact that many members would be super imposed, they would al be represented in the centre of the places. The periods of average life, which are always 1'443 times the periods of half-change, are shown for each member above or below its symbol, a ? indicating that the period is estimated indirectly from the Geiger-Nuttall relation. The figures at the head of each place represent the atomic numbers or number of the place in the periodic table, starting with hydrogen as unity, helium as 2, lithium as 3, and so on. Moseley found that the squareroot of the frequency of the characteristic X-radiation of an element was, for the K-series of radiations, propertional to integers less by one than the atomic numbers. Strictly speaking, there is no means of determining the absolute value of the atomic number, but the starting point having been fixed for any one element, the others can then be found in terms of it. Moseley assumed the atomic number of aluminium as 13, as it is the thirteenth known element in the list s arting with hydrogen as unity. It is unlikely that any new elements will be discovered between hydrogen and aluminium, although if they were it would be necessary to alter the who'e of the subsequent atomic extend over the last twelve places as far as the element thallium. At this point, it is interesting to note that the expulsion of an a- instead of a B-particle would have resulted in the production of an isotope of gold, and so literally have realised the goal of the alchemist. As it happens, a 8-particle is expelled and lead results, so far as the changes have yet been traced, in all cases as the final product. It has been necessary, in order to separate the series from one another, to displace the actinium series to the right and the radium series to the left of the centre of the places, but this displacement within the single place is not A Lecture delivered before the Chemical Society, December 19, 1918. numbers to correspond. (The position of the stellar elements of Prof. Nicholson it is unnecessary to consider here, as the Chemical Society is shortly to be given a firsthand account of this fascinating question). For X-radiations of the other series, the square-roots of the frequencies are not proportional to integers even, although the differences are nearly integral for successive elements in the periodic table. The actual numbers in the figure, 92 for uranium, for example, are derived from the assumption that the atomic number of aluminium is 13, but it is well to remember that, although relatively to one another based on experimental evidence, the absolute value is to some extent arbitrary. (We are indebted to the Chemical Society for permission to use this woodcut). The Chemical Character of the Radio-elements. During the year the missing element has been found in The simple connection between the sequence of radio- two independent investigations (Soddy and Cranston, active changes and the chemical character of the products Proc. Roy. Soc., 1918, [A], xciv., 384; O. Hahn and L. has effected an enormous simplification, not only in the Meitner, Phy ikal. Zeitsch., 1918, xix., 208). The protheory, but also in the practice of radio-chemistry. The blem as it presented itself to us was so to treat a uranium mineral as to separate an element, if present, which series extends over twelve places, two, namely, those in the families of the halogens and the alkali metals, being possessed the chemical character of the known but hopeentirely skipped. In the ten occupied places are forty-lessly short lived uranium-X2, using the latter as an indi cator in trying possible methods beforehand. The method three distinct types of matter, but only ten chemical elements. Seven of these ten, thallium, lead, bismuth, adopted, distillation at an incipient red beat in a current emanation, radium, thorium, and uranium, can now in of carbon tetrachloride vapour and air, was found to be every respect be considered, both chemically and spectro- very effective in volatilising uranium-X2 from uranium X1, scopically, thoroughly well known. These seven places and when applied to pitchblende it was found to give a accommodate all but nine of the known radio-elements, product in which none of the known pre-emanation and these nine, the isotopes of polonium, actinium, and members of the disintegration series were present. Thus was obtained a preparation from which actinium was at ekatantalum, respectively, are the only members the first absent, but which, with the lapse of time, continuously chemistry and physics of which cannot be referred to well-known elements obtainable in sufficient quantity for generated actinium, as characterised beyond the possibility of doubt by means of its active deposit. ordinary chemical and spectroscopic examination. Of these three, polonium, although the element of which at present the chemistry is best known, is likely to remain the most difficult to bring into line with the others, for, although a vast amount of exact information has been obtained as to its reactions, it would seem to remain hopeless ever to obtain it in anything but infinitesimal amount owing to its relatively very short period. The chemistry of actinium has been enormously simplified by the discovery that mesothorium 2 is isotopic with it, for the latter may be used as an indicator to show in what way the actinium distributes itself after any chemical treatment. Owing to its relatively small quantity as a branch product and to the fact that, itself, it gives no rays, the characteristic radio-activity of its products only making their appearance slowly after it has been separated, actinium has always been a difficult element to extract from the mineral and very easy to lose in chemical opera tions. There is now, however, another reason which will assist in the study of this element. The Origin of Actinium. Ekatantalum. The generalisation has now led to the elucidation of its From its origin and the discovery of its direct parent. constant association with uranium minerals, and the relative activity therein of its products in comparison with the activity of those of radium, it was considered to be a branch product of the uranium series, only 8 per cent of the atoms of uranium disintegrating passing through the actinium series an 92 per cent through the radium series. Its definite location in the periodic table, by virtue of its isotopy with mesothorium 2, made it clear that its parent must either be in the radium, or the ekatantalum place, the former if it is produced in a B-ray change and the latter if it is produced in an a-ray change. The ekatantalum place was vacant when the generalisation was first made, but it was necessary to suppose that uranium-X. like mesothorium, comprised two successive products, uranium-X, and uranium X2, both giving B-rays, and the latter occupying the vacant place in question. This prediction was confirmed within a few weeks of its being made by the discovery by F-jans and Göhring of uranium X2, or brevium, a new member responsible for the more penetrating B radiation given by uranium X, and having a period of only 1 65 minutes. The possibility that actinium was produced in a 3-ray change from an isotope of radium was experimentally disproved, and there remained only the second alternative, which was rendered a member, the more probeble by the existence of uranium-Y, discovered by Antonoff. isotopic with uranium X. and simultaneously produced with it from uranium in relative quantity such is to be expected, if it were the first Uranium Y. like member of the actinium series. uranium-X1, gives soft 8 rays, and hence its unknown product must be the isot pe of uranium-X2, and might also well prove to be the unknown direct parent of actinium in an a-ray change of long period. It should be mentioned that the exact point at which the uranium series branches has not yet been definitely ascertained, as there is a choice of alternatives, at present experimentally indistinguishable. Uranium Y may be either the product of uranium I or of uranium-II, and the latter alternative, which is that shown in the figure, is taken for the present as likely to be on the whole the more probable. The point can only be settled by the determination of the atomic weight of ekatantalum or actinium. Independently, Hahn and Meitner obtained the parent of actinium from the insoluble siliceous residues left after the treatment of pitchblende with nitric acid by adding tantalum, and then separating it and purifying it by chemical treatment. They showed that it gave a-rays of range 3 314 cm. of air at N.T.P., and, from this range, estimate its period to be from 10 to 2 10 years. There should therefore be sufficient of the element in uranium minerals to enable the spectrum, atomic weight, and chemical character of the pure substance to be determined in the same way as for radium. Its separation on a large scale will enable actinium itself to be grown in a pure state, analogously to the preparation of radiothorium from mesothorium, aud so should allow the spectrum at least of actinium to be found. With regard to the period of actinium, there is at present a real conflict of evidence, and so it is impossible to say whether our knowledge of actinium is ever likely to become as complete as that of radium, or to remain, like that of polonium, confined to what can be learned from Cranston and I, on certain infinitesimal quantities. assumptions, concluded from indirect evidence that the period of actinium was 5000 years, but Hahn and Meitner, on the other hand, state that they have obtained evidence confirming Mme. Curie's provisional estimate of the period as about thirty years, from the direct observation of the decay of the radiations of a sealed actinium preparation. Atomic Weight of Isotopes. It is clear that the periodic law connects, not primarily chem cal character and atomic weight, but chemical character and atomic charge or atomic number, which alters its value by integers, not continuously, producing the step-by-step changes in chemical character which is at the basis of the analysis of matter into the chemical elements, or heterotopes. This atomic number is, however, the algebraic sum of positive and negative charges, so that the loss of the a particle with its two positive charges and of two negative electrons as 8-particles leaves its value unchanged and produces an isotope of the element having an atomic weight four units less than the original. Un que chemical character and unique spectrum reaction is no proof of homogeneity, and so we arrive at the conclusion that the chemical elements, so far considered homogeneous, may be mixtures of isotopes, possessing different atomic structure and stability, revealed when they undergo radio-active change, and in some cases |