while the water in B, C, and D continues to boil. As soon as flasks A and E have sucked back boiling water so that they are completely filled, the lamps under flasks B and D are also extinguished. When B is quite full, flasks A and B are quickly cooled by surrounding them with cold water. The valve at F is then closed. By this means the bright specimens are immersed in water practically free from air, oxygen, or carbonic acid, and may be kept under observation for any desired length of time. This experiment has been repeated a great number of times with different samples of iron and steel, and no rusting has ever been observed unless air was allowed to enter. It has been shown that the electrolytic theory of the wet oxidation of iron is based on the premise that iron must first go into solution, an equivalent amount of hydrogen being set free. The resulting ferrous hydroxide in solution betrays its presence by producing a pink coloration with the phenolphthalein indicator. In every experiment made the pink colour was seen, although in some cases the colour developed slowly and only after the lapse of a number of hours. That the colour was not due to the action of the water on the Jena glass was shown by the fact that no colour appeared on the blank side of the experiments. Another simple experiment was made in order to determine the concentration of hydroxyl ions that must occur before a pink colour can be distinctly seen. 550 cc. of distilled water containing 1 cc. of phenolphthalein indicator was boiled down in a Jena flask to 500 cc. One one-hundredth normal potassium hydroxide solution was then run into the quickly cooled water from a burette. It was thus found that about 1 cc. of one one-hundredth normal potassium hydroxide was the limit of the quantity necessary to produce a distinctly visible pink colour; I cc. of one one-hundredth normal potassium hydroxide contains 0'00017 grm. of hydroxyl. This quantity in 500 cc. of water represents a concentration of about 0.35 part of hydroxyl per million. Since the flasks shown in Fig. 2 contain when quite full 360 cc., there must have been present a weight of hydroxyl ions approximately equal to 0'35 X 360 X 10-6 = 0.00012 grm. OH. This corresponds to an amount of ferrous iron dissolved equal to II.2 X 360 × 10-6 0'00040 grm. Fe. = In referring to Dunstan's experiment it will be seen that he boiled two small pieces of iron 1 inches square for only five minutes in 600 cc. of water. At the end of the test 300 cc. was poured off to be tested for iron. It is hardly likely under these conditions that, had this experimenter added phenolphthalein to the water, he would have reached the limit of visibility of the pink colour. Granting, how ever, that he had reached this point, it is apparent that he was making tests for iron in a solution that contained in each centimetre no more than o'000001 grm. of iron. By carefully evaporating the entire 360 cc. to dryness in a clean platinum dish, with especial precaution to avoid the entrance of dust, the writer has not only been able to show the presence of iron with the ordinary test reagents of ammonium thiocyanate and ferrocyanide, but has also quantitative evidence of the approximate correctness of the amount present, as estimated from the visibility of the colour produced by phenolphthalein. Six polished strips of iron, 2 by by inch, were boiled in flask A in the apparatus shown in Fig. 2, as already described. After the water in flask B had sucked back, flask A was allowed to stand until a pink colour was just visible. The contents of the flask were then evaporated to dryness, the phenolphthalein burned off, and the residual ferric oxide weighed. The residue weighed o 0006 grm., equivalent to o'0004 grm, of iron. Since it was thought that some doubt might be felt whether even the small amount of phenolphthalein present could attack the iron, the experiment was repeated with iron and boiled water alone, but the results invariably showed that a small amount of iron had dissolved. In view of the ease with which these experiments can be confirmed it would seem needless to yield more space to this phase of the discussion. It appears to the writer to be demonstrated that Whitney was right in his assertion that iron goes into solution up to a certain maximum concentration in pure water without the aid of oxygen, carbonic acid, or other reacting substances. This point established, it becomes apparent that the rusting of iron is primarily due, not to attack by oxygen, but by hydrogen ions. Absolute confirmation of this view will be given later on. Stimulating and Inhibiting Effects of certain Substances upon the Corrosion of Iron. All substances in solution which contain hydrogen ions, such as acids, stimulate the corrosion of iron. This is also true of salts of strong acids and weak bases, which, though perfectly stable in a dry condition, hydrolyse in solution to an acid reaction; or which, though neutral in fresh solutions, undergo slow decomposition under the action of light, with the formation of acid salts or free acid. With certain exceptions, salts which are perfectly neutral in solution do not prevent oxidation but appear to aid it by increasing the electrolytic action. All substances which develop hydroxyl ions in solution, such as the alkalis or salts of strong bases with weak acids, to a certain extent inhibit, and, if the concentration is high enough, absolutely prohibit the rusting of iron. Under the electrolytic theory the explanation of the protection afforded by hydroxyl ions is a simple one. Owing to the small dissociation of water, hydrogen ions cannot exist in a solution in which the hydroxyl ions are in excess. As hydrogen ions cannot exist or be locally formed in sufficiently strong alkaline solutions, no attack is made upon the iron, which remains permanently unaltered. If, however, the concentration of the hydroxyl ions is not sufficiently great, electrolysis can go on with an apparent stimulation of the pitting effects similar to that produced by perfectly neutral electrolytes, such as sodium chloride. As has already been noted, solutions of chromic acid and potassium bichromate inhibit the rusting of iron. In order to determine the concentration necessary to produce complete protection, a number of polished strips of two different samples of steel were immersed in bichromate solutions of increasing concentration, contained in tubes which were left quite open to the air. There were twelve tubes in each series, ranging by regular dilutions from tenthnormal down to ten-thousandth normal. At the end of two months the last four tubes showed graded rusting with accumulation of ferric hydroxide. No rusting had occurred in any of the solutions above tube No. 8, which contained six-hundred-and-fortieth normal bichromate, a strength corresponding to about 8 parts of the salt in 100,000 parts of water, or about 2 pounds to 3000 gallons. Since solutions of bichromate do not hydrolyse with an alkaline reaction, but, on the contrary, are usually slightly acid, some other explanation must be found for this remarkable phenomenon. On first thought it would seem a paradox that a strong oxidising agent should have the effect of preventing the oxidation of iron, and yet this is precisely the case. If, however, the initial cause of rusting is the hydrogen ion, it is possible to believe that under certain conditions oxygen would prove the most effective of all inhibitors. As has been stated, Dunstan, Jowett, and Goulding have claimed that this peculiar action of chromic acid and its salts is due to the fact that they destroy hydrogen peroxide. This explanation is not satisfactory, as has been pointed out, and it is fair to inquire whether the electrolytic theory is capable of furnishing a solution of the problem. Furthermore, it will be shown that additional evidence can be brought forward which cannot be made to apply to any other theory. The writer has observed that if a rod or strip of bright iron or steel is immersed for a few hours in a strong (5 to 10 per cent) solution of potassium bichromate, and is then removed and thoroughly washed, that a certain change has been produced on the surface of the metal. The surface may be thoroughly washed and wiped with a clean cloth CHEMICAL NEWS, Corrosion of Iron. without disturbing this new surface condition. No visible A The passivity which iron has acquired can be much more strikingly shown, however, than by the rusting effect proIf a piece of polished steel is duced by air and water. dipped into a I per cent solution of copper sulphate, a tensecond immersion is sufficient to plate it with a distinctly visible coating of copper which cannot be wiped off. similar polished strip of steel which has been soaked overnight in a concentrated solution of bichromate and subsequently well washed and wiped, will stand from six to ten ten-second immersions in 1 per cent copper sulphate before Even a a permanent coating of copper is deposited. momentary plunging of the metal into the bichromate will induce a certain passivity, but the maximum effect appears to require a more prolonged contact with the solution. The first explanation of this phenomenon which naturally presents itself is that a thin film of either oxide or chromate has been formed on the surface of the metal. It is almost inconceivable, however if such a film is formed, that it cannot be seen with the aid of a microscope. There is evidence which appears to indicate that no such film of oxide is formed. It is easy to cover polished iron with a visible film of oxide by simply flaming it gently in a Bunsen burner. Such films do not succeed in protecting the iron either from the rusting or the copper sulphate test. Still more convincing than this is the fact that if a polished surface which has been rendered passive by immersion in bichromate is heated to 100° C. for some hours, its passivity disappears None of the and it again behaves in a normal manner. oxides or chromates of iron are in any sense volatile compounds, so that if a solid but invisible film is really formed, it is in some manner dissipated by heat. Further than this, a chromated strip of iron which is kept in a vacuum soon loses its passivity, whereas a similar strip kept under ordinary conditions remains passive for long periods. The passivity of iron was discovered by Keir in 1790 (Phil. Trans., 1790, p. 359). Since the phenomenon is produced only by strong oxidising agents or by galvanic contact when oxygen can separate on the iron, it was explained by Faraday, Wiederman, and others (Dammer's Anorg. Chem., 1893, iii., 294) as due to a thin oxide film. From the evidence given above, however, it seems that the passivity of iron is better explained as a polarisation effect produced by the separation and retention of oxygen on the If the rusting of iron is due surface of the metal. primarily to the action of hydrogen ions, iron in the condition of an oxygen electrode should be more or less well protected from electrolytic attack. Keir (Dammer's Anorg. Chem., 1893, iii., 294) observed that polished iron which had been immersed in red fuming nitric acid was altered in some manner so that its power of precipitating silver and copper from their solutions was inhibited, and this occurred, in the discoverer's own words, without the least diminution of metallic splendour or change of colour." In the writer's experience red fuming nitric acid does not produce the passive condition as successfully as solutions of chromic acid and its salts. Mugdan discussed the passivity acquired by iron which was immersed in fuming nitric or sulphuric acids and concluded that it was not due to the formation of an oxide film, but was a true passivity in the sense of an ennobling (Vered lung) of the metal (Zeit. Elektrochemie, 1903, ix., 454) accompanied by a low electrical potential. Moody (loc. cit., p. 15) asserts that potassium bichromate prevents the formation of rust, owing to the fact that it slowly dissolves iron and its hydroxides. He observed 17 that the addition of ammonia to solutions of chromic acid and its salts which had been allowed to act on iron produced precipitates of hydroxide. This point has been carefully investigated by the writer, with the following results :-Iron which is free from manganese is not attacked by solutions of bichromate, even if boiled for days in a flask fitted with a return condenser. Manganese is. however, readily soluble in bichromate solutions, and therefore iron rich in manganese yields a sufficient amount to the solvent action to produce a small amount of brownish manganese hydroxide when the bichromate solution is poured off, made slightly ammoniacal, and allowed to stand. If metallic manganese is boiled in bichromate solutions it dissolves readily, and subsequent addition of ammonia produces an abundant precipitate of brown manganese hydroxide. If polished iron is allowed to stand for some time in standard tenth-normal potassium bichromate solution, the oxidising strength of the latter as measured by its titration value is slightly reduced without the solution of the iron or the production of any visible effect. Under the same conditions a standard solution of neutral potassium chromate is slightly reduced with the appearance of a small amount of chromic hydroxide. In fact, all the evidence obtainable points to the abstraction by the iron of some of the available oxygen of chromic acid and its salts without the formation or solution of iron oxide films. In order to show beyond doubt that an oxygen electrode is formed by immersing iron in a strong solution of bichromate the following experiment was made: - Two polished steel electrodes were prepared and chromated by immersion for a number of hours in a strong solution of The prepared electrodes were potassium bichromate. then thrust tightly through a rubber stopper which closed the Jena flask A, which was then filled with pure freshly boiled distilled water in the manner shown in Fig. 1. The electrodes were then attached to the poles of a primary battery at about 2 volts potential. At the end of half an hour, although the potential was not sufficient to disengage bubbles of gas and no visible change had occurred, the electrode which was connected to the zinc pole of the battery had lost its passivity, the other retaining it. It might still be objected that if a film of oxide had been formed it might suffer reduction at the negative pole. It is, however, very easily shown that electrodes which have been oxidised by gentle heating are not reduced under the conditions of this experiment. Wood (Am. Soc. Mech. Eng. Trans., 1895, xvi., 671) in 1895 commented on the power of paints and pigments containing certain oxidising agents, notably potassium bichromate and lead chromate, to form on iron and steel surfaces a thin coating of oxide which so effectually protects the metallic surfaces from corrosion that after the removal of the paint the metal still resists atmospheric effects for a long time, as well as the stronger effect of immersion in sea water or acidulated waters and sulphurous and other vapours. This action, Wood adds, is very obscure and not thoroughly understood; but the fact remains, and extended experiments in this field only demonstrate its presence and usefulness. The oxide film theory has been held for many years to account for the passivity of iron, but in the writer's opinion the protection afforded by certain oxidising agents is electro-chemical and not mechanical. (To be continued). Atomic Weight of Silver.-A. Leduc.-Dubreuil has recently calculated the atomic weight of silver to be 107.994 taking 0 = 16, but if O 16'027 the value obtained He also is 107 81, which is considerably lower than 108. states that the result is more likely to be correct the greater the number of methods employed to find it, but it should be observed that this is only true if all the methods are equally good, and it is actually better to rely upon one single method if the others are known to be comparatively inaccurate.-Comptes Rendus, cxlvii., No. 21. PROCEEDINGS OF SOCIETIES CHEMICAL SOCIETY. Ordinary Meeting, December 17th, 1908. Sir WILLIAM RAMSAY, K.C.B., F.R.S., President, in the Chair. On the question of admitting women to the Fellowship of the Chemical Society, the PRESIDENT was desired by the Council to make the following statement : As already announced, the recent ballot on this question showed that of those among the 2900 Fellows of the Society who voted, 1094 were in favour of, 642 opposed to, the admission of women to the full rights and privileges of Fellowship. Consequent on this difference of opinion three considerations presented themselves. 1. In 1904 the opinion of Counsel was taken as to the eligibility of women for Fellowship under the existing Charter, and your Council was advised that married women are certainly excluded, whilst the position of unmarried women is extremely doubtful, and that it would not be wise to admit women to Fellowship without first applying for a Supplemental Charter. Such a course would involve the Society in considerable expense unless, as has been suggested, the cost were met in part by the petitioners; moreover, your Council was advised on a previous occasion when application for a Supplemental Charter with another object in view was under discussion, that in the opinion of Counsel it was "highly improbable that the Government department before whom the application must come would be disposed to listen to the application unless it represented the practically unanimous vote of the Fellows, and that any active opposition by even a small minority would probably be fatal" (Proceedings, 1898, p. 38). 2. Assuming, however, that a successful application for a Supplemental Charter were made, and a certificate of candidature on behalf of a woman were presented, the ballot, if reflecting the above-mentioned figures, would result in the rejection of the candidate, because at least three-fourths of those voting must be in favour. 3. Your Council might accord to women the privilege of using the Library and attending the meetings, and allow them to purchase the publications of the Society at approximately cost price. After mature deliberation your Council has decided by a considerable majority that it would remove some of the disabilities experienced by women chemists if the following resolution were adopted. "That in the opinion of this Council it is desirable that, at any time, on recommendation by three Fellows of the Society, women be accepted as Subscribers to the Society. Such women Subscribers shall pay an annual fee of thirty shillings; they shall be admitted to all ordinary meetings of the Society; they shall have the same use of the Library as the Fellows, and they shall be supplied with the Proceedings, Transactions, and Annual Reports of the Society as these are issued." This resolution has now been adopted. It was further announced by the PRESIDENT that the Society was once more indebted to Sir Henry Roscoe for a valuable gift of books, comprising 636 volumes. The meeting endorsed with acclamation the vote of thanks already accorded Sir Henry by the Council. The seventieth birthday of Professor Dr. G. Lunge will be celebrated on September 15th, 1909, and a local com. mittee has undertaken to arrange a suitable commemoration of the occasion; the PRESIDENT stated that those Fellows who desire to show their sympathy with the festival are requested to communicate with Herrn Dr. E. Berl, Zürich IV., Sonneggstrasse 84. Mr. M. Barrett was formally admitted a Fellow of the Society. Certificates were read for the first time in favour of Messrs. George Henry Joseph Adlam, B.A., 86, Southmoor Road, Oxford; Hubert Brunskill, 7, Friarage Gardens, Hartlepool; John Wilberforce Green, 22, Alwyne Road, Wimbledon; John Esson McGillvray, M.A., 15, Regent Street, Hartlepool; William Norton Morley, B.Sc., 325, Brownhill Road, Catford, S.E.; Frederick Hubert Painter, B.Sc., Heatherbank, Alum Chine Road, Bournemouth; Colston James Regan, 14, Penerley Road, Catford, S.E.; James Thomas Stevenson, 67, Surrey Street, Sheffield. Of the following papers, those marked were tead :*266. "Silicon Researches. Part XI. Silicotetrapyrrole." By JAMES EMERSON REYNOLDS. Much of the work recorded in former papers of this series related to the action of silicon halides on aromatic compounds, including the amino-group, or its equivalent, as a side-chain. It was shown that well-defined, crystallised substances could be formed, such as Si(NH C6H5)4, in which silicon was obtained for the first time wholly combined with nitrogen. In the course of the study of these substances, it became evident that the inquiry should be carried a stage or two farther, so as to include compounds in which nitrogen forms part of a ring, as in pyrrole and pyridine. Silicon tetrachloride can be added to pure pyrrole with little effect, but when some light petroleum is poured in, complete mixture is effected and a brown condensation product, containing a small and variable proportion of silicon, separates out. This feeble action of the free base is in strong contrast with the violent interaction of aniline and the silicon compound. It was found, however, that when potassium pyrrole, C4H4NK, was treated with silicon chloride at a low temperature, energetic action ensued, potassium chloride and a crystalline substance, in fine needles, which proved to have the composition Si(NC4H4)4, being formed. This compound melts at 173° (corr.), but decomposes if heated to a materially higher temperature. Its molecular weight, as determined by the boiling-point method, agrees with the above formula. The substance differs materially from silicophenylamide, more especially in the action of heat on it. *267. "Silicon Researches. Part XII. The Action of Silicochloroform on Potassium Pyrrole." By JAMES EMERSON Reynolds. As a synthesis of pyridine from pyrrole has been effected by the action of ordinary chloroform on potassium pyrrole, it seemed possible that silicochloroform might yield a silicopyridine, that is, a pyridine ring including SiH instead of one CH group. Violent action occurs when silicochloroform is added to potassium pyrrole, and the mass becomes dark brown or black, owing to the decomposition of a large proportion of the pyrrole, but nothing definite could be extracted from the residues of several such experiments save some of the tetrapyrrole compound described in Part XI. However, when the materials used were cooled to a very low temperature, the interaction was not so violent, and a small quantity of a dark green liquid was extracted, which did not boil at 210° under a pressure of 50 mm., and decomposed rapidly above that temperature. It proved to consist in liquid air, it became a deep bronze-green solid, but of SiH (NC4H4)3 in a nearly pure condition. When cooled rapidly liquefied at the ordinary temperature. It is very easily decomposed in moist air. Another compound was obtained during the preparation of the tripyrrole derivative; this is a liquid boiling at about 135/50 mm., and has the composition SiH (NC4H4)Cl2. It is easily decomposed by water, and fumes in the air. Neither this liquid nor the tripyrrole compound exhibits any characters of a silico-nitrogen-carbon ring, but they CHEMICAL NEWS,} Jan. 8, 1909 Formation and Reactions of Imino-compounds. 19 promise to prove useful in further attempts to form such a the rate of decomposition of diazobenzene chloride, cyclic combination. *268. "Silicon Halides and Pyridine, Acetonitrile, &c." Part XIII. BY JAMES EMERSON REYNOLDS. It was inferred from the experience obtained with pyrrole that organic substances, including nitrogen wholly combined with carbon, would react feebly, if at all, with silicon halides. A series of experiments has confirmed this view so far as applies to the compounds used, namely, pyridine, acetonitrile, propionitrile, and benzonitrile. Pyridine gave with silicon tetrabromide the additive compound SiBr4,2C5H5N, and the chloride yielded a similar substance, which latter was also obtained by Harden. Acetonitrile and propionitrile also gave additive compounds of the same order with silicon tetrabromide, and much less easily with the chloride, but benzonitrile did not appear to combine with either. *269. “The Affinity Values of Tropine and its Derivatives." By VICTOR HERBERT VELEY. It was shown that tropine, the parent base of the atropine and cocaine alkaloids, has a considerably lower affinity value than piperidine, and it was concluded that the stronger piperidine residue is modified by being conjoined to the weaker pyrrolidine residue if the constitution of this base proposed by Willstätter is correct. Ecgonine, or tropinecarboxylate, possesses all the properties of an amphoteric electrolyte; its nature is in all probability that of an inner anhydride or betaine. Anhydroecgonine is a stronger base than ecgonine; the affinity value obtained was approximately equal to that of a benzenoid betaine. Benzoylecgonine in dilute solution does not remain in combination with hydrochloric acid; its basic function is, therefore, of the order of caffeine. Cocaine is a relatively strong base, although weaker than ammonia; the effect produced by the substitution of the carboxylic hydrogen by the methyl group is analogous to that previously observed in the case of glycine. The affinity value of cocaine was found to be approximately kb 25 10-7, by determining the mass of sodium hydroxide, contained in a hydrolysed borax solution, which was required to upset the equilibrium between a certain mass of cocaine combined with hydrochloric acid as a dissolved salt. = The tropeines, atropine and homatropine, have affinity values greater than kb 1 10-7; it appeared that when aqueous solutions of their hydrochlorides are heated for some time to their boiling-point, no conversion of the lactonic group into the corresponding hydroxycarboxylic acid takes place. *270. "Hydroaromatic Ketones. Part I. Synthesis of Trimethylcyclohexenone (isophorone) and some Homologues." By ARTHUR WILLIAM CROSSLEY and CHARLES GILLING. Further investigation of the trimethylcyclohexenone obtained by the interaction of ethyl malonate and chlorodimethylcyclohexenone (Proc., 1908, xxiv., 130) has proved it to be identical with isophorone. advanced by F. E. E. Lamplough in a paper bearing the above title and read before the Society in 1906 (Proc.. xxii., 280; compare also Proc., 1908, xxiv., 29), and xiv., 580), are invalid for the following reasons:-1. It is recently published in full (Proc. Camb. Phil. Soc., 1908, that "the flask usually contained pieces of broken glass definitely stated in their paper (Trans., 1902, lxxxi., 1415) for purposes of adjustment, and was well shaken during this operation (of heating the diazo-solution to the required saturation was impossible. 2. The whole of the calcutemperature) to avoid overheating," and hence superlated amount of nitrogen was measured; hence none was retained by the solution beyond the minimum quantity (which is within the limits of experimental error) ordinarily dissolved. Moreover, it was pointed out that Lamplough has overlooked Euler's proof that the reaction is accelerated by colloidal platinum, for in the experiments on the decomposition of hydrogen peroxide the platinum stirrer was coated with wax to guard against any possible action of the platinum, whilst this precaution was omitted in the experiments on diazobenzene chloride. This may well account for the higher value of the constants obtained. Further, Euler has proved by experiment that no supersaturation of the solution with nitrogen takes place in the decomposition of the diazo-solution (Annalen, 1902, CCCXXV., 295). Finally, the authors expressed the opinion that Lamplough's method of measuring the value of constants which vary enormously with the temperature (being multiplied three to four times for a difference of 10°), by omitting to carry out his experiments with a thermometer in the reacting liquid, and by heating the diazo-solution "one or two degrees higher than (the temperature of) the water-bath," which again would raise the value of the constant found, cannot be regarded as an exact one, and the conclusion was drawn that the author's determinations of the values of the constants in question (in which the temperature was carefully maintained at the correct point) are to be looked upon as being the most accurate yet recorded. DISCUSSION. Dr. SENTER said he did not think that Dr. Cain's solution could have been appreciably supersaturated under the conditions of experiment. In his experience, however, solutions in which gases were generated might become highly supersaturated under certain conditions. In the course of an attempt to determine the rate of decomposition of hydrogen peroxide by highly diluted blood (1 of blood to 500 of water) by measuring the oxygen liberated (compare Zeit. Phys. Chem., 1903, xliv., 257), it was found that if the reaction was allowed to proceed quietly for some time, and the bottle was then vigorously shaken, an immediate increase in the volume of the oxygen, amounting to several cc., was observed, although, as shown by subsequent investigation, the course of the reaction is perfectly regular. The amount of oxygen held in solution before shaking amounted at least to five times the ordinary solubility of the gas, and could not be due to chemical combination with the constituents of the blood-(1) because of the exceedingly small proportion of blood present (under ordinary conditions blood only takes up about 20 per cent of its volume of oxygen at atmospheric pressure); (2) because the gas was set free by shaking alone. The PRESIDENT remarked that certain colloidal and This method for preparing hydroaromatic ketones has been extended by using substituted malonic esters, but, unfortunately, the yields of the initial condensation products become smaller with increase in the molecular weight of the substituting group. Thus while it has been found possible to prepare dimethylethyl- and dimethyl-albuminous substances have a considerable influence in propyl-cyclohexenones, only traces of a condensation product could be isolated from the interaction of chlorodimethylcyclohexenone and ethyl isopropylmalonate, and the method would not, therefore, appear to be of any practical utility for the preparation of the higher members of the series. *271. "Note on the Determination of the Rate of Chemical Change by Measurement of the Gases Evolved." By JOHN CANNELL CAIN and FRANK NICOLL. The authors showed that the criticism of their work on causing their solutions to retain gas in solution: he alluded to the solubility of nitrogen in blood-serum. He understood from Dr. Senter that the subject is being investigated by Dr. Findlay. 272. "The Formation and Reactions of Imino-compounds. Part VII. The Formation of 1: 3-Naphthylenediamine from 3-Imino-a-cyano-y-phenylpropane." BY STANLEY ROBERT BEST and JOCELYN FIELD THORPE. In order to study the effect of concentrated sulphuric acid on benzenoid imino-nitriles containing no other sub stituting groups in the side-chain, attempts were made to prepare B-imino-a-cyano-y-phenylpropane (1) by the condensation of phenylacetonitrile with acetonitrile, but without success. It was ultimately found that this substance can be prepared by the action of alcoholic sodium ethoxide on ethyl -imino a cyano y phenylbutyrate, CH2Ph C(NH) CH(CN) CO2Et, which yields, in the first instance, B-imino-a-cyano-y-phenylbutyric acid (II.), and subsequently, by the elimination of carbon dioxide, the above imino-nitrile. Both 3-imino-a-cyano-y-phenylbutyric acid and -imino-a-cyano-y-phenylpropane pass into naphthalene derivatives on treatment with concentrated sulphuric acid, the former into 1: 3-naphthylenediamine 2-carboxylic acid (III.) and the latter into 1 : 3-naphthylenediamine (IV.) : : During the experiments on the conditions of hydrolysis of ethyl 3-imino-a-cyano-y-phenylbutyrate with one equivalent of alcoholic potash, it was found that when methyl alcohol is the solvent used the ethyl salt is completely converted into methyl B-imino-a-cyano-y-phenylbutyrate, CH2Ph C(NH)CH(CN)·CO2Me, and that when water is present the potassium compound of methyl a-cyanophenylacetoacetate, CH2Ph CO·CK(CN)·CO2Me, is the sole product. Methyl 8-imino-a-cyano-y-phenylbutyrate passes into methyl 13-naphthylenediamine-2-carboxylate on treatment with sulphuric acid. 273. "The Absorption Spectra of Para-benzoquinone, Quinol, and Quinhydrone in the State of Vapour and in Solution." By WALTER NOEL HARTLEY and ALFRED GODFREY GORDON LEONARD. derivatives in solution were examined by Hartley, Dobbie, The absorption spectra of p-benzoquinone and various and Lauder (Brit. Assoc. Rep., 1902, p. 107), and compared with the various structural formula which had been proposed for these substances. The chemical reactions of p-benzoquinone were referred to, particularly its powerful oxidising action on alcohols (Ciamician and Silber, Ber., 1901, xxxiv., 1350), and therefore alcohol had been regarded as an unsuitable solvent. Baly and Stewart (Trans., 1906, lxxxix., 506) regard water as an unsatisfactory solvent and employ alcohol. They find the curve for p-benzoquinone in alcoholic solution to be quite different from that observed by Hartley, Dobbie, and Lauder. Experiments made by one of the present authors, in 1902, seemed to show that both alcoholic and aqueous solutions under the action of light yield quinol, and the band of quinol is indicated on the curves. To ascertain the absorption spectrum of pure p-benzoquinone, photographs of the absorption spectrum of its vapour which had been already obtained were compared with those of a solution of the substance in a neutral solvent, such as ether. The results led to an extension of the work to quinol and quinhydrone, in consequence of the discovery of a reversible reaction, expressed in terms of the following equation: C6H6O2C6H4O2 + H2, when quinol vapour is heated in air to 147° at atmospheric pressures and exposed to light. When heated in hydrogen, the quantity of p-benzoquinone produced is diminished. Among the conclusions arrived at are, that ether is the only suitable solvent at all concentrations, and that under the influence of sunlight, or ultra-violet rays, an interaction occurs between the solvent alcohol and the solute p-benzoquinone which leads to the reduction of the latter to quinol or quinhydrone. By 274. "The Constitution of Para-benzoquinone." WALTER NOEL HARTLEY. In a previous paper the author has shown how the formula for benzene as proposed by Kekulé might be reconciled with those of Armstrong and von Baeyer (Trans., 1905, lxxxvii., 1823). From the evidence obtained during the investigation of p-benzoquinone, and of benzene and its homologues in a state of vapour (Phil. Trans., 1908, A, ccviii., 475), it now appears certain that neither p-benzoquinone nor quinol has a fixed and settled constitution in the strict sense of their usual symbolic representations, or the interpretations of them. It has been proved that p-benzoquinone is a benzene derivative, and furthermore, that it is possessed of a dual character in the sense that the function of the molecule can be either that of a double ketone or of a peroxide, according to circumstances. The reversible reaction described in the previous paper by Mr. Leonard and the author is now under further investigation. 275. “Benzyl Sulphoxide: A Possible Example of Dynamic Isomerism." By JOHN ARMSTRONG SMYTHE. By the action of hydrochloric acid on benzyl sulphoxide, four to six of the following compounds are produced: benzaldehyde, benzyl chloride, benzyl mercaptan, benzy! disulphide, benzyl sulphide, benzyl disulphoxide, and benzaldehyde benzyl mercaptale. The study of this reaction under different conditions has shown that it is influenced by temperature and the nature of the solvent in which it takes place; the oxygen of the sulphoxide passes over chiefly into the disulphoxide in aqueous solvents, but progressively larger amounts of benzaldehyde are formed as the solvent becomes more anhydrous and the temperature rises. To account for these and allied phenomena, it is assumed that benzyl sulphoxide exists in solution in two forms, which differ constitutionally in the position of the oxygen atom in the molecule. On the basis of this hypothesis, a series of equations involving the tautomeric forms is proposed, which gives a simple and consistent account of the formation of all the various products, and enables the hypothesis to be tested by comparison of the quantities Calulated from the equations with those found experimentally. The agreement of calculated with experimental results is held to justify the hypothesis. between the tautomerides under certain conditions to be The quantitative data enable further the equilibrium investigated, and they also show the influence of water as catalyst in the conversion of one form into the other. other reactions of benzyl sulphoxide. Confirmatory evidence of these views is obtained from 276. "The Chemical Dynamics of the Reactions between Sodium Thiosulphate and Organic Halogen Compounds. Part III." By ARTHUR SLATOR and DOUGLAS FRANK TwIss. The velocities of the reactions between sodium thiosulphate and the following halogen compounds have been measured: propyl iodide, isopropyl iodide, allyl iodide, chloroacetone, chloroacetophenone, benzyl chloride, o-, p-, and m-nitrobenyl chlorides, ethyl a-bromopropionate, and ethyl a-bromobutyrate. The great activity of the acetone derivatives is remarkable. Allyl iodide is more reactive than methyl iodide. The activity of the benzyl chlorides is of the same order of magnitude as that of methyl chloride. The iso-compounds are less reactive than the corresponding normal compounds. To explain to a certain extent the results of this and other investigations, it is suggested that the halides exist in more than one form in solution, and that some reagents react with one form and some with another. 2/7. "Note on the Optical Rotatory Power of Menthyl Cinnamate." By THOMAS PERCY HILDITCH. The author's observations on menthyl cinnamate (Trans., |