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in an atmosphere of oxygen; this can scarcely be considered a cyanogen line. There remain now the two 3584-8 and 3513-5, and, as these lines are absent from the spectra taken in oxygen and in carbon dioxide, it may well be questioned whether their origin is elementary carbon.

From their occurrence in the spectra taken in air and their being lengthened when moistened electrodes are used, it seems that for their production nitrogen is necessary and water vapour advantageous; but they are not yielded by cyanides, and, therefore, in the absence of any good reason for this, they cannot be attributed to cyanogen. A further examination of the list of lines will show that there are seven attributed to carbon by Eder and Valenta and three assigned by them to cyanogen which do not always appear when powerful sparks are passed between graphite electrodes through air. Then we have four lines of carbon and three attributed to cyanogen which do not appear when the spark is passed through carbon dioxide. Liveing and Dewar (Roy. Soc. Proc., vol. 34, p. 428) have shown that mixed vapours do not give precisely the same spectra as the substances present in the mixture would give by themselves. In certain cases one element renders the lines of another more brilliant, while in other instances some of the lines disappear. Chlorides usually have the effect of sweeping out the fainter lines.

The lines at 3590.5 and 3585.9 and 3584 are closely adjacent to certain nitrogen lines which are somewhat strengthened in the carbon spectrum. As the carbon spectrum varies remarkably under different conditions, it may exercise an influence on the nitrogen spectrum, and at the same time be modified by the presence of an atmosphere of this gas. In order to test the probability of the carbon and nitrogen spectra being subject to variations when the two elements are together in the spark or flame, it is necessary to consider the effect of one spectrum on another when the two are produced simultaneously from quite different materials.

In the oxyhydrogen flame the water-vapour lines are prominent, but only two groups are visible in the spectrum under normal conditions, and with an exposure of half an hour. If, however, some sulphur be burnt in the flame, the conditions being otherwise unchanged, then the spectrum, in addition to a band of continuous rays and flutings characteristic of sulphur vapour, shows the watervapour lines wonderfully strong, with groups extending beyond those portions of the spectrum usually photographed, and not only are the lines distinct, but dense, as if their radiating power or the chemical action of their radiations was greatly increased. This does not arise from the continuous spectrum merely overlapping and apparently strengthening the water-vapour lines, since new groups of

lines came into view which were too feeble to be visible on the other photographs. Sulphur is not the only substance which affects this spectrum, for instance, the banded spectrum of magnesia and the spectrum of lime also appear to intensify it.

It is probable that something similar takes place with regard to carbon; we know that the spectrum is modified by the surrounding nitrogen of the atmosphere, and the rays of carbon increase the intensity of the nitrogen rays adjacent to the carbon lines, the effect being increased in the case of the spark by a saturated solution of zinc or calcium chloride.

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The facts here set forth certainly favour the view that the lines in Hartley and Adeney's spectrum of carbon are the lines of the element and not merely the edges of cyanogen bands. Finally, I would point out that the carbon spectra of Eder and Valenta are not quite the same as those obtained by me, for if the photographs published in the Journal of the Chemical Society,' vol. 41, p. 91, are carefully examined with a strong magnifier, it will be seen that the graphite spectrum, No. 10, on Plate II, yields neither the group III nor group IV of cyanogen as depicted in spectrum No. 4 of the photogravure plate illustrating Eder and Valenta's paper; at the same time it may also be remarked that it does not resemble the spectrum of moistened electrodes to which I have already drawn attention.

III. "Electrical Interference Phenomena somewhat analogous to Newton's Rings, but exhibited by Waves along Wires." By EDWIN H. BARTON, B.Sc., late "1851 Exhibition " Science Scholar. Communicated by Professor ARTHUR W. RÜCKER, M.A., F.R.S. Received February 20, 1894.

(Abstract.)

1. The preliminary paper* on this subject gave the results of a single experiment, and approximately accounted for them by a mathematical theory of the phenomena involved.

2. The present paper discusses the question of disturbances, and gives nine experiments. Two of these are similar to the first experiment, but were made under better conditions; the others were made either to lead to these improved conditions or in confirmation of the original fundamental conclusions.

3. The disturbances alluded to arise from the fact that the electrical waves are not suddenly lost after their first incidence upon the abnormal part of the secondary, but course to and fro until they die out. A method of avoiding the greatest disturbance due to this cause is

'Roy. Soc. Proc.,' vol. 54, pp. 85-96, 1893.

pointed out and adopted. A correction is also calculated and applied for another disturbance which still remains.

4. The chief experiment* is on interference phenomena, somewhat analogous to Newton's rings, by transmission. The resultant curvet depends upon about 200 electrometer readings.

5. The experiments conclude with two examples of modifications of the secondary which produce no reflexion. These consisted respectively of thinner wires nearer together, and of thicker wires further apart, than the normal spacing. In each case the capacity was practically unaltered by the change in the wires; hence, as anticipated from the theory, no reflexion occurred.

6. The systematic comparison of theory and experiment, madeş near the end of the paper, does not exhibit an absolute quantitative agreement. Nevertheless, the two are so far concordant in all their general features as to be mutually confirmatory, and were approved by Professor Hertz|| as close approximations.

IV. "On Rocks and Minerals collected by Mr. W. M. Conway in the Karakoram-Himalayas." By T. G. BONNEY, D.Sc., F.R.S., Professor of Geology in University College, London, and Miss C. A. RAISIN, B.Sc. Received February 15, 1894.

(Abstract.)

During his journey in the Karakoram-Himalayas, Mr. W. M. Conway collected more than 300 specimens of rocks and minerals, generally rather small, which have been examined by the authors. They give a general summary of the results obtained, together with the details of chief interest.

Among the rocks are numerous specimens of granite and gneiss (the latter frequently pressure-modified granites), diorites, and hornblende schists, crystalline limestones and dolomites, calc-mica, micaceous, and other schists, ordinary limestones, sandstones with some conglomerates, argillites, slates, and phyllites, as well as some peculiar mottled felstones, probably devitrified acid lavas, from one locality (Golden Throne Peak). Of these rocks, the most interesting are a dark green serpentine, very like a variety common in the Alps, some hornblendites, piedmontite-schists, schists with a secondary brown mica, the crystals in one case being quite a quarter of an inch in diameter; a partially altered argillaceous rock, in which small *Expt. V, arts. 42-48.

+ Curve E, fig. 10.

Expts. VIII and IX, arts. 51–62.

§ Arts. 63-77.

|| Under whose able guidance the work was carried out in Bonn, 1892–93.

crystals of a mineral somewhat resembling ottrelite have been developed; a conglomerate, the matrix of which is rather altered, as in the case of certain "Huronian" conglomerates, and a black-garnet micaceous schist, exactly resembling a rock which occurs in the Lepontine Alps at various localities from the neighbourhood of the Lukmanier Pass to the Binnen-Thal. Several of the schists resemble those which occur in the "upper schist" group (as defined by one of the authors) in the Alpine chain. Certain rather fine-grained speckled gneisses resemble a variety of that rock common in the Blair Athol district (Scotland).

Among the minerals or vein-specimens, the most interesting is one which presents some resemblance to jadeite. Microscopic examination shows it to consist of an aggregate of minute minerals, very difficult to distinguish, and chemical analysis suggests that the most probable are lime-garnet, jadeite, saussurite, or an allied mineral, and a pyroxene. As the specimen was collected from a moraine, its origin is conjectural, but that it was a vein-specimen seems most probable.

The minerals (among others) are actinolite, garnet, idocrase, noble serpentine, pyrite, and copper ores.

The geographical distribution of the rocks is described, and it is shown that in these mountains, as in the Alps, remnants of sedimentary rocks, probably of more than one geological era, are folded in among great masses of crystalline rocks, some, doubtless of igneous origin, but others metamorphosed sediments. It is evident that here, also, the rocks, as a rule, have been greatly modified by the effects of earth-movements.

V. "Contributions to the Chemistry of Chlorophyll. No. V." By EDWARD SCHUNCK, F.R.S. Received February 15, 1894.

My previous papers were devoted to a description of various products derived from chlorophyll and their qualitative reactions. In the present communication I propose to give an account of some experiments made with a view to ascertain the composition of some of the derivatives of chlorophyll previously described.

Considerable difficulty was experienced in obtaining quantities of the various substances in a state sufficiently pure for analysis. This was especially the case with phyllocyanin and phylloxanthin, which, by the methods of purification employed so far, cannot be obtained entirely free from fatty matter. No attempt was therefore made to determine their composition. Of the compounds of phyllocyanin there is one, the phyllocyanin cupric acetate, which crystallises well, and has the appearance of a definite compound. Its composition was

accordingly determined, two analyses made by different observers leading to concordant results. Unfortunately, as previously explained, the compound is of such a nature as to make the elimination of copper and the consequent separation of the phyllocyanin impossible; otherwise the preparation of pure phyllocyanin from the compound would have been easy.

More satisfactory results were obtained in the case of phyllotaonin and its compounds. These beautiful substances being well crystallised and easily soluble in chloroform, but much less so in alcohol, may be obtained in a state of comparative purity, and I have reason to think that the numbers yielded by analysis represent, with tolerable accuracy, the composition of these bodies, although, in consequence of their high atomic weights, some doubt remains even as regards the corresponding empirical formula.

Phyllocyanin Cupric Acetate.

The preparation and properties of this compound have been previously described. Its analysis led to the following results.

I. 0.1221 gram substance gave 0-2715 CO, and 0.0577 H2O.

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The substance prepared in the manner formerly described, though apparently pure, was still contaminated with fatty matter, and had

* The details of the analysis yielding this percentage of Cu are unfortunately lost.

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