Spherical Envelope Research Articles

Liquid—Vapor Interface Potential for Water

The water molecule has been idealized as a point dipole plus point quadrupole, encased in a spherical exclusion envelope. Classical electrostatics has been applied to the determination of the potential field surrounding such a molecule in the wide interfacial region between the liquid and vapor phases, just below the critical temperature. From this result, the mean torque on the molecule in this inhomogeneous region follows, and produces a spontaneous interfacial polarization. The consequent potential difference across the interface has thus been evaluated at several temperatures, and demonstrates the tendency for surface water molecules to orient their protons away from the vapor and into the liquid. A related optical experiment is suggested, involving electric-field dependence of reflected-light ellipsometry.

Quantitative Estimation of the Loss of Membrane Images Resulting From Oblique Sectioning of Biological Membranes

Williams and Kallman pointed out one of the major artifacts in the electron microscopy of biological thin sections, namely, the failure to form images of membranes which are inclined at large angles within the section. This loss is a significant consideration in the qualitative interpretation of electron micrographs and especially in the quantitative assay of endoplasmic reticulum and mitochondrial cristae membranes. In order to estimate the effective loss of membrane images it would be desirable to use a specimen which provides a considerable length of membrane tilted at a known angle and a simple method of measuring its “visibility”. The spherical nuclear envelopes of rat liver parenchymal cells satisfy these conditions. Figure 1 shows part of a binucleate liver cell in which the nuclear membrane is clearly visible around the larger section but blurred by oblique orientation in the smaller section.

Effect of temperature changes on the maintaining voltage of a normal glow discharge

Previously published methods of estimating the change in maintaining voltage Vm of a normal glow discharge (in which an anode fall is not present) caused by a change in the envelope temperature Tw are discussed. As cylindrical tube geometry was used in each case, exact solutions were not obtained. This paper considers a spherical cathode centrally situated in a spherical envelope for which arrangement an exact solution is possible. Predicted results agree with experimental measurements. Using a simplified model of a glow discharge tube the theory is extended to include the case in which an anode fall is present. Qualitative results show that dVm/dTw, the temperature coefficient, can change from negative to positive under certain conditions due to commencement of formation of an anode fall. This conclusion is confirmed by measurement of the coefficient for an adjustable-gap tube operated in the normal glow discharge region.

Measurement of the Partial Pressure of Cesium over Cesium Antimonides

The partial pressure of cesium over the cesium antimonides whose compositions were Cs2.95Sb, Cs3.00Sb, and Cs3.25Sb was measured at various temperatures ranging from room temperature to about 180°C. The experimental tube consists of a spherical glass envelope and an ion gauge. The sample was prepared on the inner surface of the spherical envelope. The partial pressure of the cesium dissociated thermally from cesium antimonides was measured by Langmuir's positive ion method. The composition of the samples was determined by comparing their electrical resistivities and thermal activation energies associated with electrical conductivity with those of the cesium antimonides, which had a known composition. The preparation of the sample and the measuring method of the partial pressure of cesium are described precisely. The partial pressure of cesium over cesium antimonides was measured as a function of the absolute temperature, and the results showed that it was represented by the equation log10p (mm Hg) = A — B/T, where A and B are constants. In the case of Cs3.00Sb, the values of A and B were 9.040 and 6300 deg, respectively.

Thermal Conductivity: VI, Determination of Conductivity of Al2O3 by Spherical Envelope and Cylinder Methods

Values of the thermal conductivity of Al2O3 have been determined by methods employing a spherical envelope specimen completely surrounding a heat source and a long hollow cylinder in which a center section is employed for a test zone. Values obtained are in close agreement with values previously determined by other methods.

Societies and Academies

PARIS. Academy of Sciences, August 5.—M. Fouqué in the chair.—On Poisson's theorem and on a recent theorem of M. Buhl, by M. Paul Appell. The theorem of Buhl is a particular case of Poisson's theorem.—The law of pressures in cannon, by M. Vallier.—New method of preparing aniline and its analogues, by MM. Paul Sabatier and J. B. Senderens. A mixture of hydrogen and nitrobenzene vapour is passed over reduced copper kept at a temperature of from 300°–400° C., the yield of aniline being nearly theoretical. If nickel is employed instead of the copper, the reaction goes farther even at 200°, benzene and ammonia being produced-On the luminous variation of the planet Eros; curves of light; amplitude of the variation, by M. Ch. André.—On the infinitely small deformation of a spherical elastic envelope, by MM. Eug`ene and Francois Cosserat.—On a relation which probably exists between the characteristic angle of deformation of metals and the Newtonian coefficient of restitution, by M. G. Gravaris. The characteristic angle of deformation (a), and the Newtonian constant of restitution (e), appear to be related according to the equation πe=2a.—Critical study of the general theory of mechanisms, by M. G. Kœnigs.—On disruptive discharge in electrolytes, by M. K. R. J ohnson.—Remarks on a communication of MM. A. Broca and Turchini.—The electric capacity of the human body, by M. G. de Metz. It follows from the experiments described that it is illusory to compare the electric capacity of the human body with that of an ellipsoidal conductor. The same person may possess several capacities according to the conditions under which he is placed. The average figure found is about 0.00011 microfarad.—The difference of potential and the deadening of the electric spark with oscillatory character, by M. F. Beaulard.—On the transmission of Hertzian waves through conducting liquids, by M. Charles Nordmann. For the liquids studied (solutions of sulphuric acid, common salt, potassium chloride and magnesium sulphate), the maximum thickness which could be traversed by the waves employed, that is to say, the transparencies for the waves, varies in the same sense as the resistances, but not in proportion.—The vapour tension of solutions. The hypothesis of Arrhenius, by M. A. Ponsot.—An attempt at an immediate analysis of nervous tissue, by M. N. Alberto Barbieri.—On the cycloplasmic maturation, by M. Yves Delage.—Carboniferous goniatites in the Sahara, by M. Collot. The discovery of goniatites in the carboniferous layers of the Sahara points to an age a little more recent than that deduced by M. Ficheur, and it shows further that there were several levels, amongst which that which furnished the goniatites may be contemporaneous with the layers observed by Foureau in the Tassli Adzjer.—A physiological photometer, by M. G. M. Stanoïévitch.

Mirage1

WHEN a ray of light passes from point to point 01 a medium which is everywhere similarly constituted, its path is a straight line; when it passes from one medium to another medium of different density, then the ray of light is refracted or bent at the surface which separates the two media. When the ray passes from one medium to another which is denser, the refraction or bending is always towards the normal to the surface separating the two media at the point of incidence; when, on the other hand, the ray passes from a medium of a certain density to one of less density, then the bending is always from the normal to the common surface at the point of incidence. The earth is surrounded with a spherical envelope of air, and if that air were always of the same density everywhere its refractive index would be the same, and there would be no terrestrial refraction. But the spherical envelope which surrounds the earth is not all of the same density, and the refractive index of the air varies with the density. There are two causes, in the main, which militate against the uniform density of the atmosphere; one is barometric pressure, and the other is temperature. Taking no account of temperature for the moment, taking merely as the cause barometric pressure, the density of the air diminishes gradually upwards from the surface of the earth, so that the refractive index of the air diminishes upwards. The diminishing of the refractive index is not absolutely proportional to the decrease of density, but it is found by experiment to be sensibly proportional to the excess of the density over unity. The circumstance of normal refraction in the British Isles, as regards temperature, is that there is a gradual diminution of temperature upwards at the rate of about 1/300° F. for every foot of ascent. As the air gets cooler the density increases, so the tendency is to some extent to counteract the effect of barometric pressure, but it does not altogether do so. The result in the normal refraction of the British Isles is that there is a gradual diminution of density upwards.

Societies and Academies

LONDON Physical Society, April 25.—Prof. Guthrie, President, in the chair.—The following papers were read:—On the theory of illumination in a fog, by Lord Rayleigh. The paper dealt with certain theoretical results based upon the assumption that the medium in which the fog was formed and the substance composing the fog itself were perfectly transparent. The effect of such a fog surrounding a source of radiation would be to diminish the radiation, and in the case of a supply of energy from without, as with the carbon filament of an incandescent lamp, the temperature of the source would be increased by the fog. A spherical envelope of such a fog surrounding the lamp, and sufficiently thick to be impervious, would act as a perfectly reflecting surface. A problem closely related to the above, and which is easily worked out, is that of light incident normally upon a pile of glass plates. If m be the number of such plates, and ρ the fraction of incident light reflected by one plate, Φ(m) the light reflected, and Ψ(m) that transmitted by a pile of m plates, we have—

On the Vibrations of a Gas contained within a Rigid Spherical Envelope*

Proceedings of the London Mathematical SocietyVolume s1-4, Issue 1 p. 93-113 Articles On the Vibrations of a Gas contained within a Rigid Spherical Envelope* Hon. J. W. Strutt M.A., Hon. J. W. Strutt M.A.Search for more papers by this author Hon. J. W. Strutt M.A., Hon. J. W. Strutt M.A.Search for more papers by this author First published: November 1871 https://doi.org/10.1112/plms/s1-4.1.93Citations: 2 † *The problem here discussed was referred to in a paper on “the Theory of Resonance,” Phil. Trans., 1871. Its publication seems of interest, as it is the only case of the vibration of air within a closed vessel which has hitherto been solved with complete generality, except perhaps that of a rectangular parallelepiped. Considerable alterations and additions have been made since the paper was sent in the Mathematical Society, partly in accordance with the advice of Sir W. Thomson and Professor Clerk-Maxwell, and partly in consequence of my own further reflection on the subject AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volumes1-4, Issue1November 1871Pages 93-113 RelatedInformation