July 2, 1909 ABSOLUTE ALCOHOL, FREE FROM DUTY, BOOK BARGAINS. Harmsworth's "Encyclopædia," last edition, 10 vols., £2 16s. net, for cloth, 32s., half Persian, 38s.; Chaffer's "Hall Marks on Gold and Silver Plate," 6s.; Cust's Authentic Portraits, "Mary Queen Scots," FOR SCIENTIFIC AND RESEARCH WORK IN LABORATORIES. 638. for 18s. 6d.; Burke's "Peerage," 1907, 42s. for 21s., 1908, 245.; Rhead's "Staffordshire Pots and Potters," 21s. for 10s. 6d; Harvie Brown's "Travels of a Naturalist in Northern Europe," 2 vols., 63s. for ros. 6d. ; Binns' "First Century English Porcelain," 42s. net for 255 Farmer and Henley's Slang Dictionary, 7s. 6d.; R. L. Stevenson's "Edinburgh Days," 6s. for 2s.; Debrett's Peerage, 1907, 2 vols., 33s. for 6s. 6d.; Harmsworth's Atlas, 50s. for 25s.; The Green Room Book, with 40 Portraits, 5s., 1907, for 1s. 6d.; Hamilton's Secret History of the Court of England, 6s.; Balzac's Droll Stories, illustrated by Dore, 12s. 6d.; Kappel and Kirby, "British and European Butterflies," coloured plates, 25s. for 12s. 6d.; Fletcher's "History of St. Leger Stakes and History of Doncaster," 21s. for 38. 6d.; Chaffer's "Pottery and Porcelain," 42s. for 28s. 6d. Edward Baker's Great Bookshop, 14-16, John Bright Street, Birmingham. BOOKS WANTED.-25s. each offered.-Doughty's "Arabia Deserta," 2 vols., 1888; Hewlett's "Earthwork Out of Tuscany," 1895; Barrett's "Battle of Marathon," 1820; "The Exquisites," a farce, 1839; "Desperate Remedies," 3 vols., 1871; "Moll Pitcher," a poem, 1832; Keats' "Poems," 1817, 1818, or 1820; Lang's "Ballads of Old France," 1872; Last Essays of Elia," 1833; "The Snob," 1829; Omar Khayyam, Madras, 1862; Borrow's "Wild Wales," 3 vols., 1862; Brewer's "Henry VIII.," 2 vols., 1884; Burke's" Armoury and Extinct Peerage," 1883; Eliot's "Scenes Clerical Life," Ist edit., 2 vols., 1858; "Romola,” 3 vols., 1863; Freer's "Last Decade," 2 vols., 1863; Gardiner's "History of England," 2 vols., 1863; "The Germ," 1850; Jackson's "Old Paris," 2 vols., 1878; " Lorna Doone," 3 vols., 1869; Meredith's "Harry Richmond," 3 vols., 1871; Moore's" Alps in 1864"; "Life of John Mytton," coloured plates, 1835, 1837, or 1851; George Meredith's Poems," 1851; Symond's "Italian Literature," 2 vols., 1881. 100,000 books in stock. Rare and out-of-print books supplied. The most expert bookfinders extant.-Please state wants to EDWD. BAKER'S GREAT BOOKSHOP 14-16 John Bright INSTRUCTION IN St., Birmingham IPURE 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 Jorgensen, "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 performs Analyses of Yeasts, &c. Further particulars on application to the Director- PRICE ONE shilling Net. Post free, 1s. 1d. DIAMONDS. A:Lecture delivered before the British Association at Kimberley. By SIR WILLIAM CROOKES, Hon. 'D.Sc. (Oxford, Dublin, and Cape of Good Hope), F.R.8. 16, NEWCASTLE ST., FARRINGDON ST., E.C. SULPHUROUS ACID and SULPHITES. Liquid SO2 in Syphons, for Lectures, &c. PHOSPHORIC ACID and PHOSPHATES. CARAMELS & COLORINGS for all purposes. A. BOAKE, ROBERTS, & CO. (LIMITED), Stratford, London, E. To be obtained from HUGO LORENZ, 7-8, Idol Lane, Great Tower St., London, E.C., Licensed Trader in Alcohol and Spirits of Wine. Stock kept in suitable packages ready for immediate use. NOW READY. Cloth, 316; Paper covers, 216. (Postage, 4d. extra). THE WHEAT PROBLEM: Based on Remarks made in the Presidential Address to the British Association at Bristol in 1898. REVISED WITH AN ANSWER TO VARIOUS CRITICS By SIR WILLIAM CROOKES, F.R.S. WITH PREFACE AND ADDITIONAL CHAPTER, BRINGING THE With Two Chapters on the Future Wheat Supply of the OPINIONS of the PRESS. "In the present volume Sir William Crookes replies vigorously to his critics."-Liverpool Daily Post. "The student of economic science and sociology will find this volume full of interesting material. The entire subject is of the profoundest interest, and an excellent purpose has been served by the publication of these papers in a single volume."-The Eagle (Brooklyn, N.Y.). "Sir William Crookes .. has propounded a problem which in the next century [written in 1899] is bound to engage the close attention not merely of agricultural experts, but of economists and statesmen."-Speaker. "It is a vital question, and considering the cheap issue of the volume all interested in the feeding of the millions ought to get it and read it carefully.”—Crieff Journal. CHEMICAL NEWS OFFICE. 16 NEWCASTLE ST., FARRINGDON ST., E.C. SECOND EDITION. Price 28. net (post free 2s. 1jd.) Mdme. CURIE'S Thesis ON RADIO-ACTIVE SUBSTANCES. REPRINTED from the CHEMICAL NEWS. CONTENTS. Introduction.-Historical.-Chap. I. Radio-activity of Uranium and Thorium; Radio-active Minerals.-Chap. II. Method of Research.-Chap. III. Radiation of the New Radio-active Substances.-Chap. IV. Communication o Radio-activity to Substances Initially nactive.-Nature and Cause of the Phenomena of Radio-activity. CHEMICAL NEWS OFFICE, 16, NEWCASTLE ST., FARRINGDON ST., E.C. NOTICE to ADVERTISERS. All communications respecting Advertisements in the CHEMICAL NEWS should be addressed to the Sole Contractors, HAZELL, WATSON, and VINEY, Ld., 52, Long Acre, London, W.C. Conant fund THE CHEMICAL NEWS. VOLUME C. EDITED BY SIR WILLIAM CROOKES, D.Sc., F.R.S., &c. The remainder, which after cooling will be approximately solid, is taken up by 10 cc. of nitric acid, specific gravity of 12, and 50 cc. of water, and boiled. After cooling fill up to 500 cc. and filter. 50 cc. of the filtrate grm. of the substance, are treated with an ample quantity of molybdic solution (at least 100 cc. for o'r grm. P205-when the strength is greater take relatively more) and are digested on a waterbath for an hour at 50° C. After sufficient standing filter through a small tight filter. The filtrate is to be examined by addition of new molybdic solution, warming to 60° C., and standing for twelve hours for the completeness of precipitation. The remainder is washed by repeated decantations with a solution of ammonium nitrate containing nitric acid till calcium disappears. Five times washing with 20 cc. each time will be sufficient. (The calcium test is made by addition of I cc. of wash-water with a little sulphuric acid and 2 cc. of alcohol; there should be no turbidity). The remainder in the beaker-glass is dissolved in about 80 to 100 cc. of ammonia of 24 per cent and filtered on the same filter, and washed out five or six times with hot water. By this manipulation the volume of the filtrate may be increased 130 to 150 cc. Then the solution of the yellow precipitate is warmed to 60 or 80° C., and immediately the phosphoric acid is precipitated with 20 cc. neutral magnesia mixture drop by drop and with constant stirring. After standing at least four hours, or stirring for half an hour and a short sedimentation, filter it and wash out with ammonia of 24 per cent till chlorine cannot be detected. The filter and the precipitate together are brought into a crucible of platinum (if a Gooch's crucible, dry the precipitate before in the crucible), then ignite in such a way that the filter is carbonised without flame, ignite the crucible over the blast-lamp or crucible-furnace for five minutes, and weigh after cooling. The igniting must be repeated till the weight is constant. * Proposed at the Seventh International Congress of Applied Chemistry at London, May 26 and 27, 1909. Reporter, Dr. ULLMANN. On crushing the ignited residue it should be quite white throughout. Factors for Conversion. From Mg2P2O7 to P205: 0·63780. From P2O5 to Ca3P208: 2.185. Determination of Moisture. The determination of moisture in the sample for calculation of the strength in tribasic phosphate of lime in the dried matter is made at 100° C. to constant weight. Preparation of the Solutions. 1. Aqua regia.-Three parts hydrochloric acid, specific gravity 112; one part nitric acid, specific gravity 1.2. 2. Solution of Molybdate of Ammonium.-150 grms. of molybdate of ammonium are to be dissolved in 500 cc. of hot water, and 400 grms. of nitrate of ammonium are separately dissolved in water; these two solutions are to be mixed and filled up to 1000 CC. nitric acid, specific gravity 12, allowed to stand twelve The mixture is poured immediately into 1000 cc. of is considered not necessary, besides the same effect may hours at about 60° C., and filtered. Warming the solution hours. Furthermore, it must be noticed that by prolonged be entirely attained by letting stand during twenty-four standing the strength of the solution in molybdic acid may diminish by precipitation of molybdic acid. Thirty-two parts of nitric acid, specific gravity 1.2, and 3. Wash Fluid for the Precipitate of Molybdate. -The ammonium nitrate is to be examined for the absence 50 grms. ammonium nitrate are to be filled up to 1000 cc. of phosphoric acid. 4. Ammonia of 21 per cent.-Five parts of ammonia of 25 per cent, specific gravity o'91, and forty-five parts of water. Ammonia is to be examined for its purity; for instance, Pb absence. and 150 grms. of NH4Cl; dissolve them in 1000 cc. of 5. Neutral Magnesia Solution.-50 grms. of MgCl2,6H2O water. Action of Phosphorus Haloids on Platinum Metals. -W. Strecker and M. Schurigin.-By the action of phosphorus trichloride and pentachloride on iridium a compound of formula IrP3Cl12 or IrCl3.3 PC13 is obtained, and the analogous compound with bromine may be prepared similarly. Under the same conditions ruthenium yields compounds Ru2P5Cl19 and Ru2P5Br19. With palladium a less stable compound PdCl2PC13 is formed. osmium give no compounds with phosphorus haloids, rhodium metal when heated with PCI, yielding RhCl3, while with osmium no reaction occurs.-Berichte, xlii., No. 8. Rhodium and NOTE ON THE RESULTS OF COOLING CERTAIN HYDRATED PLATIN - CYANIDES IN LIQUID AIR.* By J. EMERSON REYNOLDS, M.D., Sc.D., F.R.S. In the course of Sir James Dewar's important low-temperature researches he made an interesting and significant observation with a salt which had been supplied to the Laboratory of the Royal Institution as "Lithium Platinocyanide" (see Proc. Royal Institution for 1895, p. 667). When this nearly white crystallised substance was cooled in liquid air it assumed a distinct red colour, which did not persist at ordinary temperatures, the material resuming its usual appearance. Sir James was so good as to give the writer a portion of the salt for examination, as it seemed desirable to seek for some explanation of the remarkable colour change observed. the material was ready to hand for carrying out the further comparison. This compound is, however, of a full orange red colour, at ordinary temperatures, and when cooled in liquid air becomes a magnificent ruby-red which does not alter on prolonged cooling. These observations did not, at first, seem to help much toward the end in view, but a careful study of the variations in hydration of the platinicyanide cleared away all further difficulty. The orange-red di-hydrated crystals easily dissolve in water, and form a colourless solution. When this solution is cautiously evaporated at 40° to 50° to the crystallisingpoint and then quickly cooled to 15°, long colourless needle-like crystals separate which exhibit a slight lavender fluorescence. These crystals, when collected and quickly dried by pressure, were found to include 3H2O, i.e., one more molecule of water of crystallisation than the red salt. This colourless tri-hydrate easily parts with one molecule of water, and becomes the red di-hydrate either by heat or when the colourless crystals are cooled in liquid air. the latter case, very rapid cooling always gave some yellow material in addition to the red substance, but when the reduction in temperature was carried out very slowly the red compound only was produced. In Further, when the orange-red crystals of the di-hydrated salt were very carefully heated until one of the remaining molecules of water was driven off, a yellow substance re On repeating the above-mentioned experiment several times with one and the same portion of Sir J. Dewar's specimen it was subsequently found that the substance gradually lost the property of becoming red in liquid air, and assumed instead a marked yellow colour, which was retained at ordinary temperatures. This additional phenomenon has also to be explained, as it is presumably connected with that first observed. Chemical examination of the Royal Institution speci-mained, which latter, if exposed to moist air, speedily resumed men led to the conclusion that it was a mixture of the hydrated chloride, cyanide, and sulphate of lithium with a platin-cyanogen salt of lithium, and that the proportion of the latter compound present was small. The percentages of platinum and of lithium were directly determined in the R.I. specimen, and found to be― Hence the percentage of platinum compound present could not exceed 5 per cent of the mixture of salts. When this specimen was examined under a microscope some minute red specks were seen, and these minute particles deepened much in tint when the material was cooled in liquid air. The general red coloration of the mass at the same time indicated that the platinum colour-producing compound was also diffused through the salts in a state of solid solution. The separation and identification of a small amount of a platin-cyanide in much saline material is not very satisfactory, hence the method of comparison was adopted. It seemed highly probable, having regard to all the circumstances, that the question to be decided was whether the compound present was a platinocyanide or one of the much less known platinicyanides—the presumption being, of course, rather in favour of the former. With a view to this comparison I prepared afresh some pure lithium platinocyanide, and obtained the salt in fine grass-green crystals when fully hydrated. On completely analysing these crystals they gave data agreeing well with the formula Li,Pt(CN)4,5H2O. When cooled in liquid air this salt did not alter materially in colour-its green tint simply became paler after prolonged immersion. Even when previously diffused through hydrated lithium chloride, and the mixture cooled as before, it merely assumed a somewhat more yellow shade; but neither by cold nor heat did the pure material, or the mixture, become red on dehydration. It was therefore evident that the platinum compound present in the R.I. specimen was not a platinocyanide of lithium, and was probably a platinicyanide of the same base - the latter differing from the former in containing one more cyanogen group. Happening to have in my collection a finely-crystallised specimen of lithium platinicyanide, its exact composition was then ascertained by direct analysis, and was found to be represented by the formula Li2Pt(CN)5,2H2O. Hence * A Paper read before the Royal Society, April 29, 1909. water, and became red again. I found, however, that a persistent yellow mono-hydrate could be obtained by adding to a colourless aqueous solution of the tri-hydrate a small proportion of an indifferent but highly hydrated saltsodium sulphate-then evaporating to dryness, and gently heating the residue. The red stage of dehydration was quickly passed, and a persistent pure yellow coloured product remained, recalling in appearance the yellow substance which results from the quick cooling of the pure substance, as noted above, and also the product of the repeated cooling and thawing of the R.I. specimen, as mentioned at the beginning of this note. Finally, when the pure platinicyanide was sufficiently heated, the last molecule of water of crystallisation was driven off, and a white anhydrous substance remained. It is, therefore, comparatively easy to obtain the following compounds by the means above indicated: : White Orange-red NOTE. These formulæ should probably be doubled, but it is unnecessary to do so here, as the simpler expressions serve equally to represent the essential variations. These variations of colour with degrees of hydration are doubtless to be connected with the differences in arrangement of the water molecules in the greater crystalline molecules, and their consequent effects on light. The study of these hydrates evidently supplies the interpretation of the phenomena observed on cooling the Royal Institution specimen repeatedly in liquid air. The mixture of hydrated chloride, cyanide, and sulphate of lithium used included rather less than 5 per cent of lithium platinicyanide, which was chiefly in the tri-hydrated colourless condition. When the temperature of the mixture was reduced in liquid air, one molecule of water quickly separated, and the red di-hydrated salt was formed; but on warming up to the ordinary temperature, the colourless tri-hydrate was reproduced. The other hydrated lithium salts present are doubtless simultaneously dehydrated at the low temperatures reached, although these changes cannot be directly recognised as they are unaccompanied by colour alteration. In rapid cooling of the mixed (or even of the pure) material in liquid air a little of the yellow mono-hydrate is always formed, and, as already noted, this rehydration of the yellow substance is singular CHEMICAL NEWS, } Organic Acids, &c., as Standards in Alkalimetry inhibited when neutral salts are present which are themselves avid of water, so that frequent alternations of cooling and warming gradually lead to the complete conversion of the platinum compound into the persistent yellow mono-hydrate. The facts observed regarding the chemical changes of lithium platinicyanide hydrates not only serve to explain the phenomena noted on cooling the R.I. specimen to temperatures between - 180° and -200°, but also indicate that the study of graduated dehydration of coloured salts at low temperatures may present considersble advantages, as compared with that of similar salts under the more completely disintegrating effects of heat. TABLE I. HCI value HCl value used. Grm. No. Succinic Succinic of NaOH of BaO2H2 I. Grm. 0'2000 Grm. Grm. 0.1236 2. O'2000 0.1238 3. 0'2000 O'1237 O'1235 +0.0002 4. 0'2000 5. 01235 +0.0002 7. 0'2000 In a former paper (Am. Journ. Sci., xxiii., 211) from the For the work given here a solution of hydrochloric acid was made up approximately decinormal by diluting the chemically pure acid of commerce in the usual manner. The exact strength of the hydrochloric acid solution was determined by precipitating definite amounts of it in a platinum dish in some cases, and in a glass beaker in others, by an excess of silver nitrate in presence of a few drops of dilute nitric acid. In each case the precipitate of silver chloride was allowed to stand for twenty-four hours before filtering on a weighed asbestos felt in a perforated platinum crucible. The volume in which the silver chloride was precipitated was such that after the precipitation was made it amounted to about 250 cc. The sodium hydroxide solution was made up to correspond approximately to the hydrochloric acid solution by diluting with distilled water, freshly boiled, pure sodium hydroxide prepared by the action of water vapour on metallic sodium according to the method of Küster (Zeit. Anorg. Chem., xli., 474). The barium hydroxide was prepared pure by crystallising twice commercial barium hydroxide out of hot water, washing the crystals after each purification with alcohol. A solution, approximately decinormal, was made by dissolving these crystals in a suitable amount of water and filtering into a closed bottle before diluting with freshly boiled distilled water. the sodium hydroxide solution and the barium hydroxide solution were kept in closed bottles, each connected with These a three-way stoppered burette in the usual manner. solutions were protected from the action of carbon dixoxide in the air by soda-lime tubes. introduced into these solutions by carefully drawing from the burette until the appearance of colour in the solution, due to the presence of phenolphthalein as indicator, showed the reaction to be complete. In a few cases the treatment was special, as is described. Pure succinic acid was obtained by boiling succinic ester, whose purity was established by the fact that it distilled within one-fifth of a degree, on a return condenser for four hours with water containing a few drops of nitric acid. This solution was evaporated to crystallisation and the solid product, after the removal of the mother-liquor by filtering, was re-crystallised from distilled water. After these crystals had dried in the open air to constant weight it was found that on standing over sulphuric acid in a desiccator the weight remained unchanged. For the preparation of succinic anhydride, commercial succinic acid was treated with an excess of acetyl chloride and heated on a water-bath with a return condenser at 60° as long as bubbles of gaseous hydrochloric acid were evolved from the liquid. The material, which separated out on cooling, was re-crystallised from ethyl acetate. These crystals of succinic anhydride were then washed with absolute alcohol and were dried to constant weight over sulphuric acid in a desiccator. The succinic acid used in experiments 6, 7, and 8 of Table I. had been dried for more than a year in a desiccator containing sulphuric acid, while that used in experiments 9 and 10 of the same table had been dried for the same length of time over calcium chloride in a desiccator. It is evident from these experiments that succinic acid dried in desiccators over sulphuric acid or calcium chloride for long periods of time is unaffected. be used with great exactness as standards for decinormal solutions of sodium hydroxide and of barium hydroxide. As a standard for a solution of barium hydroxide these organic acids and acid anhydrides are even more accurate in our experience than the determination of the barium hydroxide solution gravimetrically as the barium sulphate. In the various tables are given results which show the accuracy with which barium hydroxide may be standardised by the different organic substances when compared with the standard of decinormal hydrochloric acid established as the silver chloride. This same solution of the barium hydroxide which gave a value of o'006396 grm. per cubic centimetre in terms of hydrochloric acid when standardised against the organic acids and acid anhydrides, gave a value of 0.006430 grm. per cubic centimetre in terms of hydrochloric acid when standardised by precipitating and weighing as the barium sulphate by the usual procedure for the determination of barium. As standards in alkalimetry and acidimetry these organic acids and acid anhydrides, in pure state, are equally as accurate as the best previous standard-hydrochloric acid determined gravimetrically as the silver chloride. The most serviceable of these organic substances tested are those most readily soluble in water-succinic and malonic acids-although they are no more accurate than the other organic acids and acid anhydrides, as is shown by the results given in the tables. Since these substances can be readily prepared in a known state of great purity, their serviceability as most accurate standards is evident.American Journal of Science, xxvi., p. 138. Owing to the considerable length of time that is taken by succinic anhydride to dissolve in water even in the THE USE OF BAKELITE FOR ELECTRICAL presence of some alkali, experiments 20 and 22 of Table I. were slightly modified. In these the solution was heated until the anhydride completely dissolved before any of the alkaline hydroxide was added. Malonic acid was prepared pure by heating for some hours between 50° and 60° on a return condenser malonic ester, which boiled between limits of two-tenths of a degree with water in the presence of a few drops of nitric acid. The volume was then concentrated, keeping the temperature of the solution below 60° until crystallisation began, the crystals filtered off and re-crystallised out of boiling water. The pure malonic acid was then allowed to come to constant weight over sulphuric acid in a desiccator. To obtain pure benzoic acid benzoic ester was treated with sodium hydroxide in excess, and acidified with hydrochloric acid. The benzoic acid thus precipitated was crystallised twice from water and dried to constant weight in a desiccator over sulphuric acid. In all of the experiments in Table III. alkali in amount nearly sufficient to neutralise the acid was run into the flask, which was then heated. This aided materially in securing the solution of the benzoic acid in the water and did not necessitate raising the solution to the boilingpoint. Phthalic acid was prepared by boiling in distilled water some commercial phthalic anhydride. The solution was filtered while still hot; the crystalline product obtained on cooling was separated by filtration, air-dried, and finally dried to constant weight in a desiccator over sulphuric acid. The phthalic anhydride was prepared in a state of purity by distilling in vacuo the phthalic anhydride of commerce. The product obtained was dried to constant weight in a desiccator containing sulphuric acid. In Table IV. experiments 2 and 8 alone were carried on at ordinary temperatures. In the other experiments in this table the titrations were all performed after heating the solution until the phthalic acid or the phthalic anhydride used had entirely dissolved. It is evident from the results recorded in the four tables that succinic acid, succinic anhydride, malonic acid, benzoic acid, phthalic acid, and phthalic anhydride may AND ELECTRO-CHEMICAL PURPOSES.* By L. H. BAEKELAND, Sc.D. IN my first paper on Bakelite read before the American Chemical Society, I have set forth the theoretical reasons why we may consider Bakelite C., or the final product, as a polymerised compound anhydride of a phenol-alcohol and methylenglycol (see Fourn. Indust. and Eng. Chem., March, 1909, p. 149; Electrochem. and Met. Ind., March, 1909, p. III; CHEMICAL NEWS, xcix., 200). I have explained then and there how I have succeeded in producing this compound through indirect synthesis by the action of oxybenzyl alcohol on formaldehyde as well as by direct action of phenols on formaldehyde. The latter method is the more available one for practical purposes, and consists in heating under proper conditions a mixture of phenols and formaldehyde in presence of a catalytic agent, preferably small amounts of bases or alkaline substances. According to the conditions of operating, I have succeeded in carrying out the process in three phases, designated as A, B, and C. elimination of water, and contains probably one or more A is the "initial product of condensation " produced by hydroxyl groups in its molecule. B is the so-called "intermediate condensation product," a higher anhydride evolved by further elimination of water. In the case of ordinary phenol, we then have oxybenzylmethylenglycol anhydride, the formula of which may be represented as― -CH2 CH2-C6H4-O-CH2-C6H4-O-CH2-C6H4-O -CH2 -C6H4 -O -CH2-C6H4-O-CH2-C6H4. |