To the phenomena of negative polarisation might perhaps be joined another class of phenomena. In the cathodic polarisation of mixtures of nickel sulphate and zinc sulphate, of the sulphates of nickel and iron, and of zinc and iron, the polarisation rises frequently up to the value of the baser metal, and this latter metal is likewise deposited (A. F. Walter von Escher, "Kathodische Vorgänge bei der Elektrolyse gemischter Lösungen von Zink- and Eisersulfat," Dissertation, Dresden, 1912; a full literature list will be found there; compare also F. Foerster, "General Electrochemical Behaviour of Metals," Zsit. Elektrochem., 1908, xiv., 153). These processes are not pure examples of negative depolarisation, however, because in the absence of the less noble metal the more noble one is deposited quantitatively, i.e., with a current efficiency of 100 per cent; at the same time hydrogen is generated. These cases are worthy of attention when one of the two metals at least in the salt mixture which is being electrolysed belongs to the cathodically passive

metals.

To these experiments, which, as we shall see, introduce us into the ante-room of the passivity phenomena, others may be added, which initiate us directly into the secrets of passivity.

a

4. Direct Experiments on the Passivation of Metals. Surprise has often been expressed at the fact that a metal turning passive does not, at higher current density, show at least that anodic solubility which belongs to it at small current density. Let a passive metal be dissolved anodi. cally at a low current density a to the extent of 50 per cent, and let it liberate oxygen, so that its dissolution takes place at amp./cm. of metallic surface. When we increase the current intensity tenfold, the dissolution will not proceed at the rate of 5a amp./cm.2; it does not even take place at the former rate amp., but at a much smaller rate. How is this to be interpreted chemicokinetically? Let us assume that a passive metal Me generates primarily oxygen. Two reactions are possible :

2

a

2

1. Me+O+2H→ Me + H2O. 2. 0+0 02.

The commencement of reaction (2) is designated "passivity." The example teaches us that passivity is not a result of two competing reactions, for both of which the velocity would increase with increasing oxygen concentration, but the passivity is caused by two reactions such that the velocity of the one reaction decreases with increasing O concentration, whilst the velocity of the second reaction regularly increases with increasing Ỏ con

centration.

In 1911 I set myself the task to investigate how the rate of increase of the anodic polarisation potential accompanying the flow of continuous current through a Pt-H2SO4 electrode differs in the two cases when the Pt electrode is free from oxygen and when it has previously been charged with O2 (Reichinstein, Zeit. Elektrochem., 1911, xvii., 89; 1913, xix., 672). I made the following observations:-A current impulse is imparted to the combination

Pt | 28 per cent H2SO4 | clay cell-KI-I | Pt

in the direction of the arrow. Its anodical amplitude is o'1 amp./cm. of the Pt electrode, its duration o'026 second. After the expiration of this period follows a spontaneous diminution in the electrode charge lasting o'028 second. The rest of the anodic charge is then destroyed by shortcircuiting the cell for 0.025 second. These three processes succeed one another. (The arrangement comprises a

rotating commutator which closes the primary circuit, interrupts it, and closes the short-circuit; the latter could be opened and closed at will during an experiment with the aid of a cut-out). In this way it was possible to obtain, on a photographic plate, oscillographs of the time potential curves at open and at closed short-circuit.

At open short-circuit this time-potential curve rises steadily up to an asymptotic potential value, which is independent of the time. At closed short-circuit the curve marks a point of inflection corresponding to the moment 0.004 second after closing the circuit. This point is well marked on the oscillogram, and the experiment is easily to be reproduced. I have been able to show this with the aid of the oscillographs at different times to several scientists.

This point of inflection can only be interpreted as indicating that we have to deal with a chemical reaction, the velocity of which first increases and then decreases, as the current quantity (i.e., together with the oxygen concentration) is increasing. During a period which is smaller than tendency of approaching the time ordinate and a stationary 0'004 second the time-potential curve has the distinct value at low potentials. Every approach to a stationary condition now is connected with an increase in the velocity of the compensation process, i.e., of that process in the absence of which the stationary conditions could not be reached. Now we observe a point of inflection within o 004 second after closing the circuit, when the potential rises; the velocity of the compensation process is beginning to fail.

Thus the curve velocity-oxygen concentration possesses a maximum.

The compensation process consists of the formation of platinum oxides (see below).

During a period which is smaller than o'004 second, therefore, a Pt | H2SO4 electrode behaves, at a current density of o'r amp./cm.2, like an inattackable electrode. The amount of Pt oxide which is formed per sq. c., when the continuous current is not interrupted, is hence of the order of magnitude 0'004. 01/96540=4. 10-9 grm.equivalent.

When afterwards the electrode is polarised for some time with the short-circuit closed, the electrode becomes covered with a yellowish layer which consists of Pt oxides. This does not occur when the short-circuit is open. We remember that platinum is dissolved with a high current yield in KCN solutions by alternating currents, but not by continuous currents. A combination, continuous currents superposed on alternating currents, is utilised in the gold industry.

A lucky accident has led us to the direct experimental recognition of the described maximum of the curve, in which the velocity is plotted as a function of the oxygen concentration.

In Russia a large amount of gold is gained by dissolving the ores in aqueous KCN solution in the presence of air as oxidising agent. This process being very slow, there has been no lack of attempts of trying other oxidising agents.

In this connection Andrejew (Journ. Russ. Phys. Chem. Soc., 1907, xxxix., 1637; Nachricht. Polyt. Inst., Petersburg, 1908, ix., 447; Zeit. Elektrochem., 1913, xix., 667) and later Michailenko and Meschterjakow (Fourn. Russ. Phys. Chem. Soc., 1912, xliv., 567)-—on the instigation of Kistiakowsky-determined the rate of solution of gold in KCN in the presence of oxidising agents. They all found that this dissolution takes place in such a manner that the rate first increases and then decreases with the concentration of the oxidising agent. The velocity-concentration curve displays a well-marked

maximum.

We may now pass to the exposition of the theories which aim at bringing all the cases of chemical polarisation under one point of view.

(To be continued).

In order to test this, sodium lactate, intimately mixed with soda-lime, was destructively distilled in an iron tube under reduced pressure at a temperature just below redness. A distillate was obtained consisting of two layers, an upper one consisting of a brown oily liquid, having an odour of peppermint, and a lower aqueous one. By saturating the aqueous portion with solid anhydrous potassium carbonate a liquid was separated which turned out to be acetone. The brown oily portion of the distillate appeared to consist mostly of mesityl oxide.

It is evident, therefore, that ethyl alcohol, if formed, is at once oxidised. This is not surprising when it is remembered that alkalis can act as oxidising agents at high temperatures. One might imagine that the ethyl alcohol is first oxidised to acetic acid, which then loses water and carbon dioxide, giving acetone. This, by condensation of two molecules losing water, would give mesityl oxide, thus,

This by oxidation gives acetone, which then undergoes condensation, giving mesityl oxide.

It is thus evident that in these pyrogenic reactions the theoretical first products are only formed, when they are highly stable compounds (such as saturated hydrocarbons). Otherwise oxidation and dehydration occur. A fact to be noted is that very little charring takes place during the heating.

Time did not permit of further experiments with other hydroxy acids being carried out, especially as the results obtained were, on the whole, negative.

University College, Gower Street, W.C.

Dextro-camphorates of Potassium.-E. Jungfleisch and Ph. Landrieu.-The authors have prepared and studied the properties of the following four compounds of potassium and camphoric acid :-Dipotassium d-camphorate, monopotassium d-camphorate, monopotassium d-dicam phorate, and monopotassium d-tetracamphorate. The first of these is very stable and is not decomposed by water, while the others are very unstable in presence of water and decompose to give the dipotassium camphorate and camphoric acid.-Comptes Rendus, clvii., No. 19.

COLUMBIUM v. NIOBIUM.

THE Editor has received the following communication and letter from Prof. F. W. Clarke :

Dear Sir William,-I enclose a brief note which I should like to have inserted in the CHEMICAL NEWS. I think English chemists should stand up for their country. man. Yours sincerely,

F. W. CLARKE.

At a meeting of the Council of the International Association of Chemical Societies in Brussels last September a Committee on Inorganic Nomenclature, among other recommendations, endorsed the name and symbol "niobium" and "Nb" for the element which was originally named columbium. As this recommendation is historically erroneous, a brief statement of the facts appears to be desirable.

In 1801, Hatchett, an English chemist, analysed a strange American mineral, and in it found a new metallic acid; the oxide of an element which he named columbium. A year later, Ekeberg, in Sweden, analysed a similar mineral from Finland, and discovered another element, which he called tantalum. Wollaston, in 1809, undertook a new investigation of these elements, and concluded that they were identical; a conclusion which, if it were true, would have involved the rejection of the later name and the retention of the earlier columbium. The accepted rules of scientific nomenclature make this point clear.

For more than forty years after Hatchett's discovery both names were in current use; for although Wollaston's views were accepted by many chemists there were others unconvinced. In 1844, however, Heinrich Rose after an elaborate study of columbite and tantalite from many localities, announced the discovery of two new elements in them, niobium and pelopium." The latter supposed element was afterwards found to be non-existent, but the niobium was merely the old columbium under a new name. That name in some mysterious manner was substituted by the German chemists for the original appropriate name, and has been in general use in Europe ever since. In America the name columbium has been generally preferred, and was formally endorsed by the Chemical Section of the American Association for the Advancement of Science more than twenty years ago. In England also columbium

is much used, as, for example, in Roscoe and Schorlemmer's "Treatise on Chemistry," Thorpe's "Dictionary of Applied Chemistry," and the new edition of the "Encyclopædia Britannica."

The foundation of Rose's error seems to have been an uncritical acceptance of Wollaston's views; for he speaks of all the minerals he studied as tantalite. He also, at least in his original memoir, claims that the atomic weight of niobium is greater than that of tantalum, and here he was obviously wrong.

In short, the name columbium has more than forty years priority, and during that interval was accepted by many chemists, and was more or less in current use. Το employ the name niobium is not only unhistorical, but it is also unfair to the original discoverer, meaningless, and without any justification whatever. Furthermore, it injures the splendid reputation of Rose, for it perpetuates and emphasises one of his few errors. The recommendation of the Committee above mentioned should not be accepted, for it is opposed to the established rules of priority.

Fluorine as a Constant Constituent of the Emanations from the Earth's Core.-Armand Gautier.Fluorine is always found to be present when the following are examined :-The minerals formed in crystalline rocks, thermal springs, emanations from the soil, volcanic gases, and gases from solfaturi. All these products have a very deep-seated origin. Other elements also frequently accompany it, viz., boron, sulphur, nitrogen, arsenic, chlorine, bromine, iodine, silicon, carbon (as CO2), sodium, free hydrogen, copper, &c.-Comptes Rendus, clvii, No. 19.

of 50 metres thick, the least crack in connection with the deep ground sends forth an abundance of smoke. More to the south, at Combes, thirty or forty years ago, the flames issuing from the cracks of the mountains illuminated all the country round during the night. Since then the intensity of this furnace has decreased; nevertheless it is still in activity, the ground is burning hot, and when it rains the mountain is enveloped in mist and steam. A part of the ground to the north of Crausac is called the Etuve (vapour-bath or oven). By digging down into the soil for a dept of 50 centimetres you arrive at an oven of 50°. There was formerly a mineral magnesium spring there, and these natural baths or ovens were employed in the treatment of certain maladies. After the tracing of the galleries of the mines the spring disappeared. How. ever, there is another one of the same kind at Combes. Quite lately, as has been reported by M. G. Patrouilleau, the presence of the subterranean fire to so very far from the surface has been remarked in the town of Decazeville itself. Some workmen who were digging in one of the streets of the town a cutting for laying an armoured cable of 3000 volts, remarked with surprise that, for a length of about 20 metres at about 1 metre's depth, temperature rose to 75° C. The cable was laid, armoured, and isolated by paper, by suspending it in a kennel with lateral chimneys or aeration. From the upper chimney hot air and large quantities of steam come forth. According to the inhabitants of the town this elevation of temperature might have been foreseen, for indeed in the portion of the street under consideration the snow does not lay and the rain water is quickly evaporated. M. Patrouilleau says that from the calcined vestiges found in the basin the fire is in a state of retrogression, but the layers of coal intact are so powerful and so close together that an extension of the Scourge, due to subterranean landslips, for example, is always to be feared.

THE ZODIACAL MATTER AND THE SOLAR CONSTANT. The existence of little intermercurial planets may be revealed by the observation of the perturbations that their masses determine, as well as by the reflection of the solar light and by occultations at periodic intervals. In particular the long periodic inequalities that are to be met with in the theory of the moon may be explained by the existence of a swarm of little intermercurial planets circulating near the sun (Radan, Shint, Blancat). Lastly, the fact that in the month of March the southern edge of comets is brighter than the northern edge, which is further removed from the earth, may be explained by admitting that the zodiacal light represents the elliptic projection of concentric rings crossed by swarms of planets. The passage of these swarms twice a year, in May and November, before the sun seems to be accompanied, according to MM. Abbot, Towle, and Aldrich, by slow and periodic variations of the solar constant, amounting to 5 per 100 in about from seven to ten days.

Colloidal Properties of Meta-hæmoglobin. Modification of Viscosity and Surface Tension of Suspensions by HCl and NaOH.-Filippo Bottazzi.-An aqueous suspension of pure meta hæmoglobin has about the same viscosity and surface tension as distilled water. When, under the action of HCl or NaOH, the meta

hæmoglobin passes into solution the viscosity of the liquid

increases and the surface tension diminishes, the reverse taking place when the acid or alkali is neutralised. When the viscosity has been increased by the addition of HCl it begins to decrease if an excess of acid is added. The addition of sodium chloride produces a small but constant diminution of the surface tension. The lowering of the surface tension depends principally on the undissociated molecules of proteïn:-Atti della Reale Accademia dei Lincei, xxii [ii.], No. 6.

"Intermittent Vision." By A. MALLOCK, F.R.S. When a wheel turns so rapidly that the separate spokes cannot be seen or easily followed by the eye, and if at the same time the observer receives a small mechanical shock of almost any kind, the spokes appear almost stationary for a fraction of a second.

The appearances depend on the speed of rotation, on the brightness of the illumination, and, to a lesser degree, on the nature of the shock. Suitable shocks are given by the contact of the feet with the ground as in walking by tapping the head or body, and in many other ways.

The convention by which rapid rotation is indicated in drawings, namely, that of introducing a large number of radial lines in place of the actual spokes, probably has its origin in one form of the same phenomenon.

In the paper some experiments are described bearing on the relation between the appearances and the speed of rotation, and an explanation is suggested depending on an assumed variation of sensibility produced by a slight shock. This variation, which it appears is rapidly extinguished, has a periodic time of about 1/18 second, but this differs slightly for different individuals.

"Attempts to Observe the Production of Neon or Helium by Electric Discharge." By Prof. the Hon. R. J. STRUTT,

F.R.S.

The present experiments were begun in the hope of confirming the work of Collie and Patterson (Trans. Ċhem. Soc., 1913. ciii., 419; and Proc. Chem. Soc., 1913, xxix., 217). The results have been negative, whether from a failure to appreciate the proper conditions for the pro duction of neon by electric discharge through hydrogen or from some other cause.

The test for neon was carried out so that the amount found in 1/100 cc. of air could easily be detected.

It was found difficult or impossible to be sure of excluding air, when the hydrogen was pumped out from one apparatus and transferred to another by pneumatic trough manipulation.

This kind of manipulation was avoided. The hydrogen, after each experiment, was converted into water by admitting a little oxygen into the discharge vessel and continuing the discharge for a short time at intervals. The resulting water vapour was frozen out in a side tube cooled by liquid air. Diffusion was free enough to soon remove the whole of it, and a pure oxygen discharge remained. The oxygen could easily be removed by cooled charcoal. Thus the entire series of operations were carried out in one closed apparatus. The discharge with electrodes in a cylindrical tube was tried, both at the cathode ray stage and at higher pressures; also the electrode-less discharge. The duration of each experiment varied from 8 to 20 hours. In no case was any trace of neon observed.

"The Relations between the Crystal-symmetry of the Simpler Organic Compounds and their Molecular Constitution." Part III. By WALTER WAhl.

"The Selective Absorption of Ketones." By Prof. G. G. HENDERSON and I. M. HEILBRON.

Many aliphatic ketones containing one of the groups —CH2.CO— or —CO.CO—, as well as their derivatives, absorb selectively in the visible and ultra-violet regions. Some at least of them exist in keto and enol modifications, R.CH2.CO.R' and R.CH:C(OH). R', and according to one hypothesis their absorption is due to some intramolecular vibration which occurs when one tautomeric form changes