CHEMICAL NEWS, Relective Properties of the Copper-Ferrocyanide Membrane. April 27, 1917 digestion. The human system can also probably more readily assimilate the mineral matter of the germ than that of the husk. Experiments on pigeons have shown that when they are fed on wheat deprived of the germ they developed neuritis, but that they remained healthy when it was retained. But the special advantage of wholemeal, and of 80 per cent flour, to which the Bread and Food Reform League has always directed prominent attention, is the presence of a large quantity of mineral substances, especially phos. phates, which form bones and teeth, and nourish the brain, nerves, and tissues. PROCEEDINGS OF SOCIETIES. ROYAL SOCIETY. Ordinary Meeting, March 29, 1917. 201 Sir J. J. THOMSON, O.M., President, in the Chair. PAPERS were read as follows: "The Fourth Colourless Sensation in the Spectrum Sensation Curve when Measured in the Centre of the Retina." Sir WILLIAM ABNEY, F.R.S. The Minnesota experiments do not deal with this aspect of the subject, but those made at Cambridge confirm the statements of the League. Prof. T. B. Wood, when describing these experiments in "The Composition and Food Value of Bread," contained in the R.A.S.E.tunity of working some of them out. Journal in 1911, states. At the end of the last century the author carried out a large series of observations on the luminosity of spectra of very low intensity, but only recently he has had an oppor He has some time ago published in the Phil. Trans. the three-colour sensations which apparently suffice to The 80 per cent bread contained rather more than account for all the spectrum colours. There was a doubt twice as much phosphoric acid as the white bread. The if in the mixture of the sensations to form these colours percentage digested was exactly the same in the two some account ought not to be taken of the colour sensation cases, 52 per cent. It follows therefore that the 80 per which appears when a coloured ray is diminished in intencent bread supplied to the tissues twice as much phos-sity for all colour to be absent and only a colourless residue phoric acid per day as the white bread. Wholemeal contains four times more phosphoric acid than patent white flour. The Bread and Food Reform League has always taught that when the meal is ground to a uniform fineness a very large proportion of this can be assimilated. Digestion experiments by Prof. Goodfellow showed that in "wholemeal bread containing very fine particles of bran nearly 60 per cent of the ash was dissolved." Opinions vary as to the amount of phosphates required, but as they are of such vital importance, especially for the young, and as Nature does not work in minimums, it is judged safer to have an abundant supply of such essential elements. Dr. Wiley, of America, states in his recent book, "Not by Bread Alone," "There is no longer any doubt of the fact that the demineralisation of our foods, especially the cereal foods, is unscientific, unwise, and unnecessary. A generous mineral diet, as Nature has prepared it, is a necessity for the growing child and a desirability for the grown person." is left. The author confines himself to the colours received on the centre of the retina, for on the periphery other conditions exist. The paper shows the method of observation which was employed, and, discussing the results, the author comes to the conclusion that the admixture of the colourless sensation with the three-colour sensations is so small as to be inappreciable, and that the sensation curves given in his paper, to which reference has been made, need no correc. tion on this account. "Magnetic Inertia." By G. W. WALKER, F.R.S. It is shown that a magnetised body may be expected to possess magnetic inertia, just as an electrified body possesses electric inertia. In the case of a sphere of radius a and magnetic moment m the inertia for acceleration parallel to the magnetic axis is-2 m2a-3C-2, is 5 Finely-ground wholemeal and genuine 80 per cent flour, when made from the same wheat, have more protein than and for acceleration perpendicular to the magnetic ax's fine white flour, a larger amount of valuable phosphates, and the essential vitamines, which are eliminated from fine white flour. Their adoption will help to improve the general public health, promote temperance, and prevent a great deal of illness. As bread constitutes the principal diet of many poor children, it is of vital importance that they should be able to obtain it in its most nourishing form, so that they may be better able to maintain health and strength, and thus help to secure a strong vigorous race to carry on the work of a great Empire. MAY YATES (Hon. Sec. Bread and Food Reform League). 5, Clement's Inn, London, W.C. 2 (C is the velocity of radiation). The order of magnitude of this inertia is considered in an astronomical as well as in an atomic connection. "The Selective Properties of the Copper-Ferrocyanide Membrane." By F. TINKER. In the present paper the selective properties of copper ferrocyanide have been studied by measuring the change in solution concentration which takes place when the dry colloid is immersed in cane-sugar solutions of various strengths. It is found that the sugar solutions become stronger owing to the fact that the water and not the sugar is taken up selectively by the ferrocyanide. The experimental results lead to the hypothesis that a colloidal hydrate, Cu2FeCy6 3H2O, is first formed, and that this colloidal hydrate then takes up still more moisture by adsorption. The amount of "adsorbed " moisture taken up by the colloid decreases as the strength of the solution increases. The fact that colloidal copper ferrocyanide adsorbs water selectively from cane-sugar solutions without taking up the sugar at the same time supports the author's theory that the property of selective permeability is (in the case of colloidal membranes) a result of preferential adsorption. It is also shown in the paper that the side of a mem. brane in contact with pure water has a greater moisture content than the side in contact with sugar solution. This fact supports the hypothesis-first advanced by Graham on experimental grounds-that osmosis across a membrane | been found to conform to that of the more concentrated takes place because pure water induces a greater moisture pressure and concentration inside the membrane than the solution does. d =3 = K(C−c) (F(c, ()} 2p Exp - log F (, ) dx } = = = C) π {=- a where K is a constant, 2p the angle at the prow, x the inclination to the axis of the z real of the tangent at the point of the boundary where (= §, and— F(EC)=(6-8){ - - i (a2 - §3) } / ¦ — §§ +a2 − i (a2 − ) (S2-a2) For a convex obstacle it is shown that the most forward points at which it is physically possible for the free streamlines to break away are determined by the relations acids previously examined, and it has been found that the rate of dissolution of the aluminium rises continuously until the concentration of the acid falls to I per cent. With the more dilute acids it was found that the rate of dissolution was increased by the presence of the products of the interaction. The influence of this factor grew very rapidly with increasing dilution, so that in the case of 1 per cent acetic acid the rate of dissolution rose as the experi ment proceeded to more than five times its initial value. is not yet possible to assign a definite cause to this phenomenon, but it is obvious that a practical deduction can already be made from the facts observed. Where aluminium vessels are to be used in connection with dilute acids, the greatest care must be taken in their design to avoid small recesses or pockets in which the circulation of the contents cannot take place freely, and in which, therefore, the products of the interaction can accumulate. Attention has been called to this fact in considering the effect of other acids on aluminium (Fourn. Soc. Chem. Ind., xxxv., 665), and the correctness of the view now expressed is fully borne out by experience in practice. In all cases where the action of boiling acetic acid of whatever concentration has been examined, the attack is uniform and no evidence of local action has been observed. The only exception is the peculiar case of anhydrous acetic acid described in the previous communication. The rate of attack by cold acetic acid is, in general, small. As in the case of boiling acids, the rate of dissolu tion increases with increasing dilution of the acid. The highest rate so far noted took place with a solution con. taining o'02 per cent acetic acid. Local action was also noted in the case of very dilute acid exposed to intensive aeration. In dealing with cold acetic acid it has been possible to show conclusively the effect of oxygen in promoting such local action. Acids which normally cause local action of a serious kind can be made to act perfectly uniformly if the oxygen be entirely removed or if it be replaced by some inert gas. In the case of cold acids it has also been found that the actual rate of dissolution is raised by the presence of oxy. gen. Here, again, it may be well to point the practical moral of the observations made. Vessels used to contain solutions of these acids should not be allowed to remain wet for prolonged periods after being emptied and before cleaning. In such cases the metal is exposed to the action of thin films of acid subjected to intense aeration, and, as practical experience has amply demonstrated, local attack frequently ensues. The metal should be purged as soon as possible of any remaining acid, and, where possible, left dry. One of the original objects of this research was to find an explanation for the fact that in stills used for the distillation of acetic acid the still proper was often found to have a prolonged life, whereas the condensers, notably in their lower part, were frequently subjected to rapid deterioration, due to local perforation. It would appear that the effect of oxygen in promoting such attack affords a sufficient explanation of this phenomenon, because it is precisely at the point where this attack has been observed in condensers that access of oxygen to surfaces bathed in hot acids would take place. The question arises whether difficulties owing to this of some neutral gas at this point. cause could not be completely obviated by the introduction The rates of dissolution of aluminium in 10 per cent and 80 per cent acetic acid, both in the cold and at boiling temperature, were compared with the rates obtained after the addition of small quantities of sodium chloride, potas. sium bromide, potassium iodide, sodium sulphate, and potassium nitrate to the acetic acid. With 10 per cent acetic acid the addition of up to 1 per cent sodium chloride, potassium bromide, potassium iodide, or potassium nitrate has been found to be practically negligible in the case of boiling acid, whereas an equivalent amount of sodium sulphate raises the rate of dissolution appreciably. In cold 10 per cent acid, however, I per cent of sodium chloride is sufficient to raise the rate of dissolution tenfold, whereas potassium bromide effects a much smaller increase in the rate of attack, and potassium iodide and nitrate none at all. o'5 per cent of sulphuric acid, in the form of sodium sulphate, raises the rate of dissolution fourfold in the case of io per cent acetic acid at the ordinary temperature. In the case of 80 per cent acetic acid in the cold, I per cent of sodium chloride raises the rate of dissolution from 3.6 to 270 mgrms. of aluminium dissolved per 100 sq. cm. per twenty-four hours. The same amounts of potassium bromide and iodide increase the rate of dissolution approximately tenfold; 0.5 per cent of sulphuric acid, in the form of sodium sulphate, cannot be said to have any effect on the rate of attack by 80 per cent acid in the cold; and potassium nitrate reduces the rate of dissolution to a fourth of its previous value. The most serious effect of the addition of impurities is noted in the case of 80 per cent acid at boiling temperature. Here the rate of dissolution is raised by the addition of 1 per cent of sodium chloride from 290 to 16,000. By 1 per cent of potassium bromide the rate is only increased from 290 to 485, whilst potassium iodide and nitrate may be said to have no effect. 0.5 per cent of sulphuric acid, in the form of sodium sulphate, does somewhat increase the rate of attack. The form of attack by acids to which the salts named were added appears to be of considerable importance. In general it may be stated that acids which without addition attack aluminium in a uniform manner are not affected by the addition of these salts except that where the rate of attack is raised considerably etching of the surface may be observed. Where, however, the acids alone cause local action, such local action is generally promoted by the presence of halogens, but retarded by the presence of small quantities of sulphuric acid, and absolutely inhibited by as little as o'r per cent of nitric acid. It has also been found that small quantities of nitrates may largely or entirely neutralise the effects of the presence of chlorides. DISCUSSION. Dr. C. A. KEANE asked if the authors had noticed any thing in the action of acetic acid which might have a disturbing effect. The generation of hydrogen might cause the formation of aldehyde, which would be difficult to detect in the presence of acetic acid. The formation of aldehyde would not occur with the dilute acid. Oxygen acting as a catalyst with aldehyde and acetic acid present might have a very important effect. Mr. E. J. BOAKE thought that the fact that the action of acetic acids of various strengths was not uniform pointed to an effect of the purity of the aluminium. On one occasion, when a thermometer had been broken in an aluminium still, a hole had eaten right through the metal at the point where the mercury had been in contact, the hole being larger than the drop of mercury, so that corrosion had taken place over a larger area and pern eated the metal in the neighbourhood. Mr. W. C. REYNOLDS asked whether the presence of small traces of ammonia had any effect on the action of various substances on aluminium. A MEMBER said it would be interesting to know the composition of the aluminium used in the experiments. Mr. E. T. BREWIs said that he would like to know if the authors had made any experiments on the action on aluminium of a fairly pure water highly aerated. Dr. A. C. FRYER asked whether the figures given for dilute acetic acid might be safely taken as applicable to butyric, propionic, and the lower fatty acids generally. Mr. W. C. HANCOCK considered that the specimens shown indicated that oxygen was the cause of the pitting, but he was also in agreement with Mr. Boake that the action was due to some impurity in the metal. Had the authors made any experiments in which the aluminium had been partly exposed to the air and partly immersed in the acid 203 Mr. BREWIS enquired whether the authors had noticed any difference in the behaviour of aluminium treated in various ways-e.g., cast, hammered, or rolled--and whether this metallurgical treatment causes any variation in the corrosion referred to? Dr. S. MIALL asked if the authors proposed to inveeti gate the action of acetic acids on other metal. The action on aluminium reminded him of the variations in the action of acetic acid on lead. Dr. SELIGMAN, in reply, stated that they had never met with any purer aluminium than the samples they had experimented with. The possible action of impurities had not been lost sight of, and he wished that a sample of the absolutely pure metal was obtainable. With regard to the action of mercury, that metal formed an alloy with aluminium, and although amalgamation might occur at one point the area of action was greater and deeper, and a hole might be eaten right through the vessel. Aluminium containing o5 per cent of copper was not attacked by mercury at all. In reply to Dr. Keane he said that acetaldehyde was formed, but it was difficult to realise how a product of reduction should form the means of attack unless it was suggested that the re-oxidation of the aldehyde might explain it. He did not think that oxygen was the main cause of pitting, but that it was necessary for pitting. The action of the lower fatty acids in general was still under investigation. He did not propose to undertake the investigation of the action of acetic acid on other metals at the moment. "Nitrated Castor Oil." By R. BRIGHTMAN, The author obtained nitrated castor oil by the action of warm dilute nitric acid on castor oil. The nitrated castor oil so obtained is a reddish brown viscid oil, soluble in acetone, ether, alcohol, and acetic acid, but insoluble in carbon disulphide. It has a specific gravity of about 105, and is best characterised by determining its nitrogen con tent by a modification of the Kjeldahl process. The percentage of nitrogen is usually about 30. The author concluded that the nitrated oil consists of the triglyceride of the nitric ester of oxidised ricinoleic acids. This view rests mainly on the facts that all the nitrogen is removed on saponification, the drop in the iodine value on nitration, and the proved presence of complex oxidised acids. Mr. WALTER F. REID was glad to hear that the subject was being worked upon, because the nitro-compound of castor oil ought to be of use in industry. Nitration carried out with weak acid was incomplete. The acid should have been of sp. gr. 1:5. The presence of water caused oxida tion and the formation of free fatty acids. The nitrogen content should be between 4 and 5 per cent; certainly over 4 per cent. The best test he had found for nitrated castor oil was the specific gravity. The author's figure, 105, agreed fairly well with those he had found-namely, I'127. Physical Society.-The next meeting of the Physical Society will be held at the Imperial College of Science, Exhibition Road, South Kensington, S.W., on Friday, April 27, 1917, at 5 p.m. The following papers will be read:-"A Note on the General Equation for Wave Motion in an Elastic Medium," by Prof. J. A. Fleming, M.A., D.Sc., F.R.S. "The Effect of Stretching on the Thermal Conductivity of Wires," by A. Johnstone, B.Sc. "Cohesion," by Prof. H. Chatley, D.Sc. CORRESPONDENCE. THE DEFINITION OF "MATTER." To the Editor of the Chemical News. SIR, -In reply to Mr. F. H. Loring's note on "The Principle of Extended Terms" (CHEMICAL NEWS, 1917, CXV., 159) I should like to say that I entirely fail to see how this so-called principle justifies the definition of "quantity of matter" as "equal to or identical with mass." I venture to suggest that if the expression "quantity of matter" does, indeed, mean nothing more than "mass," then it is an entirely unnecessary expression and may well be deleted from scientific terminology. But the useis of the word "matter," as Ostwald, who rightly refuses to employ a word so unnecessary and confusing, points out (vide "The Fundamental Principles of Chemistry," §7), generally attach a more intensive meaning to the term than would be the case were "quantity of matter" a mere synonym for "mass." Indeed, Mr. Loring himself, later in this note, writes "we do not yet know whether the negative electron has weight and can be classed as matter," and in the same paragraph refers to “inertia” (which he has already equated to "mass") as a "property" of "matter." I would, indeed, ask Mr. Loring carefully to consider in his mind what the term "matter" really does mean for him, and I think he will find that it stands for a very complex notion-a notion, moreover, which, being not purely experimental in origin but based upon speculation, is foreign to science and belongs to metaphysics. And, in conclusion, I would add, with reference to Mr. Loring's admonition that "more is to be accomplished by thinking in extended terms and in terms of experiment than by introducing the subtlety of logic," that logic is merely a name for sound thinking, without which nothing can be accomplished save confusion of thought.—I am, &c., H. STANLEY REDGROVE. West Ham Municipal Technical Institute, Stratford, Essex. CHEMICAL NOTICES FROM FOREIGN SOURCES. NOTE-All degrees of temperature are Centigrade unless otherwise expressed. Comptes Rendus Hebdomadaires des Séances de l'Académie des Sciences. Vol. clxiv., No. 5, January 29, No. 6, February 5, 1917. These numbers contain no chemical matter. No. 7, February 12. Absorption of the Ultra-violet Radiations by some Chlorine Derivatives of Ethane, Ethylene, and Acetylene.-MM. Massol and Faucon.- Hexachloroethane, although very rich in chlorine, is relatively transparent to the ultra-violet rays. The absorption for radia. tions of short wave-length diminishes with the dilution for solutions in absolute ethyl alcohol, but no absorption bands appear. Acetylene tetrachloride shows about the same degree of transparence. Pure ethylene tetrachloride, in a layer 1 mm. thick, absorbs all the radiations from A=271. The authors examined acetylene in solution in alcohol and in pure acetone and acetone diluted with alcohol. The absorption was found to be considerable, having regard to the small quantity of acetylene dissolved. All radiations of small wave-length are absorbed. The transparence increases with the dilution. but no absorption bands were observed. Mixed Anhydrides derived from Benzoylacrylic Acid.-J. Bougault.-When phenylisocrotonic acid is dissolved in water with a slight excess of alkaline bicarbonate and iodine is added, an insoluble iodolactone is precipitated. In presence of a large excess of sodium carbonate no lactone is precipitated, but the phenylisocrotonic acid is transformed into benzoylacrylic acid. If a large excess of a sodium salt of an organic acid only slightly soluble in water, benzoic acid for example, is added to the mixture in the last reaction a mixed anhydride is formed, for C6H5.CO.CH – CHCO. example, in this case, C6H5.CO O. The two isomeric a-bromocinnamic acids give similar mixed anhydrides with benzoylacrylic acid, and the anhydrides obtained are not identical but isomeric. It seems probable that a lactone is formed as an intermediate product in this reaction. Nos. 8 and 9, February 19 and 26. These numbers contain no chemical matter. MEETINGS FOR THE WEEK. MONDAY, 30th.-Royal Society of Arts, 4.30. (Howard Lectures) "The National Shortage of Iron Ore Supplies," by Prof. W. G. Fearnsides. TUESDAY, May 1st.-Royal Institution, 3. "Tetanus-Its Prevention, Symptoms, and Treatment," by Prof. C. S. Sherrington. Roy Institution, 5. (Annual General Meeting). WEDNESDAY, 2nd. - Royal Society of Arts, 4.30. "Herb-growing in the British Empire-Its Past, Present and Future," by J. Chapman Shenstone. Society of Public Analysts, 8. "Estimation of Phenacetin and Allied Compounds by mean of Hypochlorous Acid," by A. D. Powell. "A Rapid Method for the Determination of Nickel and Cobalt in Ores and Alloys," by W. R Schoeller and A. R Powell. "Sote on Opium Poisoning Cases," by J. Webster THURSDAY, 3rd.-Royal Institution. 3. "Pagan Religion at the Time of the Coming of Christianity-Misleading Preconceptions-The Raw Material-Dea Roma," by Prof Gilbert Murray, Royal Society. (Croonian Lecture). "The Excitation Wave in the Heart" by Dr. Thomas Lewis. FRIDAY, 4th.-Royal Institution, 5.30. "Some Guaran ces of Liberty," by H. Wickham Steed. SATURDAY, 5th.-Royal Institution, 3. "The Electrical Properties of Gases," by Prof. Sir J. J. Thomson, O.M. A TEXT-BOOK OF THERMO-CHEMISTRY AND THERMODYNAMICS. By Professor OTTO SACKUR, Ph.D. Translated and Revised by G. E. GIBSON, Ph.D., Instructor in Chemistry in the University of California. 8vo. 12s. net. THE ATHEN.EUM.-"As a work dealing especially with the relations of thermo-dynamics and physical chemist y, this book should be of considerable value for reference and study." NEW EDITION JUST PUBLISHED. THEORETICAL CHEMISTRY FROM THE STANDPOINT OF AVOGADRO'S RULE AND THERMO-DYNAMICS. By Professor WALTER NERNST, Ph.D. New Edition, Revised by H. T. TIZARD, M.A. 8vo. 15s net. MACMILLAN & CO., LTD., LONDON. CHEMICAL Nzwa Advertisements, BRITISH-MADE TRANSPARENT QUARTZ GLASS A MORE THAN PERFECT SUBSTITUTE FOR THE FINEST LABORATORY GLASS OR PORCELAIN PRODUCED IN ANY COUNTRY. NEW PRICES and SAMPLE free on application to THE SILICA SYNDICATE, Ltd., 82 HATTON GARDEN, Telephone-Holborn 6380. LONDON, E.C. |