CORRESPONDENCE. THE PEOPLE'S UNION FOR ECONOMY. To the Editor of the Chemical News. SIR,-On July 16 last we wrote a letter on the extreme gravity of the financial position of this country, which you were good enough to publish. We were glad to observe the gradual awakening of interest in this matter, and the attention which all sections of the community are beginning to pay to the critical state of affairs. In order to promote further the views we expressed in July last the People's Union for Economy have now established their headquarters at 1, King's Buildings, Millbank, Westminster, S. W.1. The People's Union for Economy will aim at keeping a watchful eye upon all Government expenditure with a view to directing attention to overlapping and waste in the administrative sphere. For this purpose it will operate through a strong Parliamentary Committee including members of all parties and of both Houses of Parliament, and they will seek to co-operate with other Associations working for the same objects. The Central Office aims further at becoming a bureau of information where all Parliamentary papers and estimates will be critically examined and filed for reference. It will be in constant touch with commercial and industrial bodies, individual economists and others in all parts of the country, with a view to providing the best possible material for criticism. It is obvious that an organisation of this kind, which we believe to be without parallel in the country, must rely for its development upon the support of the public, whose interest it is solely designed to serve. We therefore invite all those who agree with the views we have expressed to give us their support by joining the Union, and by supplying reliable information of any instances of public waste and extravagance. Forms of membership may be obtained on application to the Hon. Secretary, Mr. Leslie HoreBelisha, 1, King's Buildings, Millbank, S. W.1.— We are, &c., SALISBURY ASKWITH MIDLETON EMMOTT OSWALD MOSLEY GODFREY LOCKER-LAMPSON ISLINGTON C. W. BOWERMAN Mr. ERIC TOMKINSON makes the following addition to his letter on "The Colour of Water' inserted in last week's issue :— "It should be remembered that the molecular formula of water, determined from surface tension measurements, was found by Ramsay and Shields (Zeit. physikal Chem., 1893, xii., 464; Journ. Chem. Soc., 1893, lxiii., 1089) to be (H2O), at o°." HALOGEN DERIVATIVES OF LEAD AND THALLIUM -They should, it appears, form well defined combinations. By varying the ratio of the two compounds in a mixture of T1 and Pb, in aqueous solution, M. Barlot successively isolated PbBr2, TlBr, PbI,Tl and TeC1PbCl,.-Comptes Rendus, October 21, 1920. NOTES. ROYAL INSTITUTION.-On Tuesday next (January 18), at three o'clock, Sir G. P. Lenox-Conyngham will give the first of two lectures at the Royal Institution on "The Progress of Geodesy in India"; on Thursday (January 20), Dr. Arthur Harden begins a course of two lectures on "Biochemistry (Vitamins)"; and on Saturday, January 22, Dr. P. C. Buck commences a course of three lectures on the "Madrigal: Rhythm-Key-Technique," with musical illustrations by the English Singers. The first Friday evening Discourse on January 21, will be delivered by Sir Frank Benson on "Shakespeare and Democracy"; and on January 28 by Sir James Dewar on "Cloudland Studies." £20,000 FOR INDUSTRIAL HARMONY.-Of the many New Year honours conferred by His Majesty none was more deserved than the Baronetcy bestowed upon Col. Sir Wm. Dupree, J.P., D.L., who, early in the great war, foresaw that one of the greatest problems that would evolve from the conflict, and which would shake nations to their foundations, would be the question of relationship between employers and employed. Events that have happened in all countries of the world during the last twelve months have clearly proved the wisdom of Sir Wm. Dupree's judgment of what would be the trend in industrial matters. Serious though the situation has occasionally been in England, this country has happily been spared the terrors of civil strife, and it can with all deference be said of Sir Wm. Dupree, as of other like public-spirited men, that his broad-minded munificence and indefatigable energy have contributed materially to the factors which have enabled England as far to avoid the industrial rocks and snags on which she would undoubtedly have foundered. So keen was Sir Wm. Dupree on what he felt to be his duty to his countrymen in this connection that in December, 1918, he approached the Rt. Hon. G. H. Roberts, M.P., who was then President of the Industrial League, and placed in his hands for the use of the League, and without any reservations whatever, a cheque for £20,000. THE ACTION OF COPPER ON MOULDS.-The existing opinion in favour of the employment of anticryptogamic bouillies is based upon the theories of Millardet applied to hydrated copper oxide. Continuing the studies already submitted to the Academy, M. and Mme. Villedieu demonstrate that the metal Cu is not more toxic for Peronospoaceae than for moulds, and that vine stocks are not protected against mildew, although sufficiently bathed with ammoniacal nitrate to find the metal in the ash from tissue of the leaves. Thus it seems possible to replace copper in the mixtures hitherto employed by some less expensive elements.-Comptes Rendus, October 18, 1920. ACTION OF SELENIUM ON MOULDS.-The experiments of Messrs. Nemec and Varchav Kàs related to various varieties of Mucdinea sown in a Raulin liquid modified according to their specific needs and mixed with seleniate of sodium. The influence of Se was especially notable with P. Roqueforti, but in the case P. Candidum, the metal apparently becomes toxic when the percentage exceeds a certain limit.-Comptes Rendus, October 18, 1920. is passed over chalk or barium carbonate until a sufficient concentration of acetate is obtained, and at the same time the methyl alcohol and acetone are withdrawn by means of vacuum. The wash-water contained in the tank A is pumped into the vessel B, provided with a heating jacket, where it passes through lumps of calcium or barium carbonate, and overflows through the pipe bi into the vessel D, which also contains calcium or barium carbonate and is fitted with a cooling jacket. The methyl alcohol and acetone are drawn off from the heated wash-water in the vessel B by means of the pump b into the condensing coil C. The liquid issuing from the vessel D is pumped into the tank E, from which it can be run back to the scrubbers of the suction gas plant. The process is repeated until the content of calcium or barium acetate is sufficient to justify its recovery by evaporation. Messrs. Rayner & Co., will obtain printed copies of the published specifications and forward on post free for the official price of 1/- each. MEETINGS FOR THE WEEK. Monday, January 17, 1921. Royal Society of Arts, 8. "Aero Engines," by Alan E. L Chorlton. Tuesday, January 18. Royal Institution, 3. "The Progress of Geodesy in India," by Col. Sir Gerald P. Lenox-Conyngham. Society of Chemical Industry. (At Edinburgh). Mineralogical Society, 5.30. The Olivine Group," by A. F. Hallimond. "A method of rock-analysis diagrams based on statistics," by W. A Richardson. "Identity of Trechmann's 'B-tin' with Stannous sulphide," by L. J. Spencer. "Linarite, Caledonite, and associated minerals from Cumberland," by G. F. Herbert Smith. "On the Adare and Ensisheim Meteorites," by G. T. Prior. Institution of Petroleum Technologists, 5.30. Wednesday, January 19. Royal Society, 4.30. "The Magnetic Mechanical Analysis of Manganese Steel," by Sir Robert Hadfield, S. R. Williams the Design of Diaphragms capable of continuous Tuning," Royal Society of Arts, 4.30. "The Future of Industrial Management," by F. M. Lawson. Royal Microscopical Society, 8. NOTICES. EDITORIAL.-All Literary communications and Books, Chemical Apparatus, &c., for review or notice to be addressed to the EDITOR. SUBSCRIPTIONS, £1 12s. per annum, payable in advance, should be addressed to the MANAGER. BACK NUMBERS and YOLUMES can be purchased on application to he MANAGER. THE CHEMICAL NEWS, 97, SHOE LANE, LONDON, E.C.4. ADVERTISEMENTS. All communications for this Department should be addressed toT. G. SCOTT & SON, 63, LUDGATE HILL, LONDON, E.C.4. PATENTS, TRADE MARKS. Handbook and advice free-B. T. KING, British and U. S. Regd. Patent Attorney, 146a, Queen Victoria St., London. 35 years reference COVERS FOR BINDING. Cloth, Gilt-lettered, Covers for binding the Half-yearly Volumes of the CHEMICAL NEWS may now be obtained. Price 2/- each (post free 2/3). Volumes bound in Cloth Cases, Lettered, and Numbered at 35. per volume. CHEMICAL NEWS OFFICE, 97, SHOE LANE, LONDON, E.C.4. CHEMICAL APPARATUS AND REAGENTS. Pure Chemicals for Research Work. JOHN J. CRIFFIN & SONS, LTD.. (KINGSWAY, LONDON, W.C. STRONTIUM SULPHATE (Average sp. gr. 3.95). THE CHEMICAL NEWS. VOL. CXXII., No. 3171. THE STORING OF LIGHT. (A HISTORICAL REVIEW OF INORGANIC PHOSPHORESCENCE.) By J. FREDERICK CORRIGAN. No department of history can offer a more peculiar and fascinating study than that which deals with the introduction of mankind to the natural phenomena, and which traces the early struggles and progress of a crude science founded on mystery and superstition, towards the elucidation of the problems of nature. The histories and legends of kings and princes, fair maidens and chivalrous knights, of fearsome monsters and enchantments give, it is true, a thrill of pleasurable excitement to the reader, but in all of them something is lacking-an undefinable something which is ever present in the romance of the eternal quest for truth. A romance, however, which under certain aspects is pathetic, tinged with sorrow and with blighted hopes; a story of the struggles of early man against darkness and mystery, and with the crude ineffective tools of his own forging. Every new idea, every newly-discovered fact is an additional step forward along the lonely tortuous road which marks the path of science. But at what cost is each advance made? At the expense of almost Herculean effort, heroic self-sacrifice, and untiring devotion. + Phosphorescence, as a natural phenomenon, is widespread. It occurs in various guises, both in the living and in the mineral world. Its first introduction to mankind would most probably take place in the remote age when some poor rude uncivilised man was first frightened out of his wits on noticing the luminous appearance of decaying animal matter. This phenomenon he would ascribe to the "soul" of the animal rising forth to reveal itself to him, and subsequently luminesence would always be associated with the supernatural.* A phosphorescent object would be regarded as being "Luminous, gemlike, ghostlike, deathlike."+ In the same way, the first prehistoric savage, who, on dipping the oar of his primitive canoe into the placid tropical waters and finding that it emerged irridescent, shining with a pale ghostly light, would doubtless have had the phenomenon of phosphorescence very forcibly impressed upon him. And then, as time went on, luminous flyinginsects and beetles would be noticed, although as yet fire would be an unheard-of thing. Needless to say, these insects would be invested with a sou! and would be preserved as sacred. This is borne out by the fact that the earliest records of phosphorescence occur in the early Eastern manuscripts, where reference is made to the sacred insects of the Temple, which in the darkness shone with a light of their own. Biblical allusions to gems which shine in the dark may also occasionally found. Even at the present time, "apparitions" are invariably associated with luminous phenomena. Tennyson: "Maud," Pliny was acquainted with the luminous appearance of decaying animal and vegetable matter. He also refers to certain precious stones which shine in the dark. It is customarily supposed, however, that apart from these few observations of Pliny, the phenomenon of phosphorescence did not attract much attention until the mediæval discoveries of the various "phosphoruses." It is more probable that the 16-17th century discoveries of the phosphorescent alkaline-earth sulphides were merely rediscoveries of facts known long before the Christian era. Such circumstances are not wholly unknown to science. A strong point in favour of this view is found in Berthelot's discovery in certain 13th and 15th cen tury manuscripts of various translations of Greek alchemical writings. Amongst them, Berthelot found recipes explaining methods of "colouring artificial precious stones, emeralds, carbuncles, hyacinths, according to the book taken from the shrine of the Temple." The authority of several alchemical writers is quoted, including Agathodemon, Democritus, and Ostanes, and a close study of the writings leaves no doubt as to the acquaintance of the ancients with methods by which stones could be rendered phosphorescent simply by coating them with a thin layer of a substance already phosphorescent. Further evidence may be also obtained from Livy (xxxix., 13): "Matronas Baccharium cum ardentibus facibus decunise ad Tiberium demissoque in aquam faces, quia vivum sulphur cum calce insit intergra flamma efferre." Which, with a certain ease of translation, may be rendered: "The Bacchantes would run down to the Tiber with burning torches, and plunging them into the water, would take them out with the flame unextinguished because they were covered with a mixture of living lime and sulphur." Thus it is apparent that even the phosphorescence of calcium sulphide was known centuries before it was "discovered" by Marggraf in 1750. Passing rapidly over a gap of nearly a thousand years, during which time the knowledge of phosphorescent substances appears to have been completely lost, we find at the beginning of the 16th century, Benvenuto Cellini in his "Art of Jewellery" putting on record the fact that some precious stones had been observed to shine in the dark; also the observation of Albertus Magnus, that diamonds when moderately heated, became luminous. However, the first discovery which attracted the then rising scientific attention was that of Vincenzo Cascariolo, a cobbler of Bologna, who, in 1639 (according to some authorities, 1602) noticed that when a particular kind of earth found in the neighbourhood was heated in a certain manner, it acquired the remarkable property of emitting a soft, ghostly light after a certain amount of exposure to the rays of the sun. This substance was called by its discoverer lapis solaris, and on account of its power of attracting and storing up the golden rays of the sun, it was considered by Cascariolo to be nothing less than the long sought for Philosopher's Stone. The Bologna Stone was treated as a discovery of the greatest import. Learned treatises where written on the subject by the philosophers of the day, amongst whom were F. Licetus, a professor of philosophy at Bologna, Celias, Potterius, and Kircher. Frequent attempts at its chemical analysis were made; speculations as to its nature and origin were entertained, but with little success. Science was not yet sufficiently free from the fetters of alchemy to enable any real progress to be made. About this time (1609), Brandt of Hamburg had discovered phosphorus, by distilling a mixture of concentrated urine and sand, at a red heat. Being the possessor of business instincts as well as of alchemical attainments, he jealously guarded the secret of the preparation of the Phosphorus Mirabilis, and it was only after some time that he sold the secret to Krafft for a considerable sum of money. Krafft brought the phosphorus over to England, where the specimens exhibited created an enormous sensation. A new zest was added to the production of phosphorescent bodies, and the secret of the preparation of Brandt's Phosphorus was much sought for. Eventually, however, Kunkel (1678) and Boyle (1680) succeeded in effecting a preparation by means of methods similar to that of Brandt. Boyle was also attracted to the study of other forms of phosphorescence. He had observed that diamonds gave out light when heated or rubbed, and in 1663 he investigated the phenomenon of the phosphorescence of decaying organic matter. Beccarius also made a searching examination of various substances, and he claimed to have found that "almost everything in nature imbibes more or less light, and emits it again in the dark." He divided bodies into several classes as they were phosphorescent "with or without preparation.” Almost all vegetable and animal substances, when perfectly dry, he considered to possess this property, which was particularly well exhibited in the case of paper. an In 1677, G. A. Baldwin, of Misnia, whilst engaged in a search for the Philosopher's Stone, discovered that the product obtained by dissolving chalk in nitric acid, shone brightly in the dark, after exposure to sunlight for a few minutes. Great interest was again aroused by this discovery, and Baldwin, who was formerly a bailiff, found himself suddenly raised to the rank of honoured philosopher. In a letter to the Royal Society (Phil. Trans., 1676, ii.), he says: "This phosphorus contains the real spark, yea the most secret soul of the fire and light of nature, and consequently the innate and invisible fire of the philosophers; attracting magnetically the visible fire of the sun, and afterwards emitting and diffusing in the dark, the splendour of the same." The discovery of Baldwin's phosphorus was particularly welcome, as the preparation of the Bolognian stone had been kept more or less secret. The new discovery, however, threw some light on the matter, and it was followed some little time afterwards (1764) by the discovery of Canton's phosphorus. Canton prepared his phosphorus by calcining oyster shells with sulphur, and it is to his credit that he was really the first who attempted to systematically investigate the phenomenon. He found that the phosphorus could be made to shine by heating it, after its spontaneous phosphorescence had ceased. He devised experiments whereby the intensity of the light which excited the phosphorescence could be compared, and he also noted that the phosphorescence took place equally readily under alcohol or ether, but that water appeared to have some action on the substance. Hom On the analysis of Bologna stone and its identification as a sulphide of barium by Marggraf (1750), and because of the progressively increasing scientific methods displayed in investigating the phenomenon, the preparation of phosphorescent substances became more frequent, and many were the uses to which these bodies were put. berg's phosphorus (CaCl,) was sold in phials and used for illuminating the dials of watches and timepieces in the dark. Celestial objects, such as Saturn and his ring,* the phases of the moon, &c., were represented by cutting the object in wood and smearing the surface of it with a paste composed of equal parts of the white of an egg, and (Canton's Phosphorus) (Priestley's "History of Light and Colours,” 1772). In addition to the phosphorescence of the alkaline-earth sulphides, by means of which the sun's rays were seemingly absorbed and stored up, other types of phosphorescence began to be discovered. Reference has already been made to Boyle's observations on the phosphorescence of diamonds when heated or rubbed. In 1705, Francis Hawkesbee observed that friction between two glass surfaces "in common air, in the vacuum of an air pump, or under water" produced "a very considerable light." Du Fay noticed that some substances "shone with unusual splendour while they were dissolving, and thereby heated, in water but this did not continue long." D. Hoffman discovered that certain felspars were luminous when rubbed together, and Pott added flints, certain crystals, and porcelain to the list of substances which gave out light when rubbed. Thomas Wedgwood, however, is generally credited with the discovery of "Luminosity by Attrition." In an extended paper on "The Produc tion of Light from Different Bodies, by Heat and Attrition (Phil. Trans., xvii., 128, 215), he separated substances into : (a) Bodies giving out light on warming. (b) Bodies evolving light on attrition. With regard to the former class, he found that the substances were by far the most luminous when they were first heated; that the duration of the light produced varies to a large degree, in some cases being almost momentary, and in others lasting for several minutes. Bodies of the latter class he found to be only luminous when rubbed. As soon as the rubbing was discontinued, the luminescence disappeared. Wedgwood was also the first to point out the yet unexplained fact that bodies emit a peculiar odour on attrition. He found it to be most persistent when the friction was greatest, and also to be independent of the light produced, as it was often present when the light emitted was practically nil. But here we must draw a close to this brief sketch of luminescence throughout the ages. After the time of Wedgwood, the chain of observations and discoveries, never markedly coherent, becomes hopelessly broken and entangled in the oncoming tide of the scientific revolution which began about this period. In conclusion, however, a few remarks on the early theories of phosphorescence may be opportune. Evelyn in his "Diary" (1650) refers to phosphorescent powders and preparations as a means * Only one ring was known at this period. |