On the experimental determination of the index of refraction of liquefied gases

On a previous occasion I had the honour to present to the Royal Society some results of an investigation made about electrical conductivity of chemical compounds, and I then chiefly examined the liquefied gases, pointing them out as very bad conductors. I have since been engaged in studying another property of these substances, and I have succeeded in determining in an experimental way their refractive power. As in England and abroad several papers have been subsequently published bearing on the relation between the liquid and gaseous conduction of matter, and especially liquefied gases present themselves well adapted to this kind of research, I hope the Royal Society will consider my paper not devoid of interest, the more so because our knowledge of their physical constants is somewhat limited. And though we possess numerous determinations of the refractive power of a vast number of chemical compounds, still increasing daily, I have found only very little information concerning my subject, this being limited to sulphurous and prussic acid, that are readily liquefied by cold and present no difficulty in manipulating. Faraday in his extensive paper on liquefied gases, published in 1823, when describing the properties of several of them, compares only their index of refraction to that of water, calling it more or less, and Brewster in 1826 mentioned in a communication to the Society of Edinburgh the index of refraction of liquefied cyanogen as 1⋅316, but without any remarks on the manner in which it was deduced. I will commence this paper by describing the method I followed to obtain the numerical values of the index, of refraction of several gases, liquefied either by pressure or by cold, and that enabled me to surmount the difficulties resulting from high tensions and small quantities of fluid substance, that may perhaps have kept back other experimenters from this field of research.

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III. On electrical conductivity and electrolysis in chemical compounds

Proceedings of the Royal Society of London ◽

10.1098/rspl.1876.0053 ◽

1877 ◽

Vol 25 (171-178) ◽

pp. 322-327 ◽

Cited By ~ 2

Keyword(s):

Electrical Conductivity ◽

Royal Society ◽

Chemical Compounds ◽

Considerable Time

In presenting this communication to the Royal Society I wish to state that it is only an abstract of a more extensive paper on the same subject which I hope to publish shortly, and which contains an account of experiments with nearly seventy substances, most of which were never used before for such an investigation. I tried also nearly all the liquefied gases, and a considerable time was spent in preparing them for this kind of research, that was often interrupted by fearful explosions. The invaluable opportunity which Mr. Warren De La Rue, F. R. S., granted me some time ago to try the same compounds with his very powerful battery, led to results which I hope the Society will not consider devoid of interest.

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XVIII. “On the Experimental Determination of the Index of Refraction of Liquefied Gases.”

Proceedings of the Royal Society of London ◽

10.1098/rspl.1884.0137 ◽

1884 ◽

Vol 37 (232-234) ◽

pp. 191-191

Keyword(s):

Experimental Determination ◽

Index Of Refraction

XVIII. “On the Experimental Determination of the Index of Refraction of Liquefied Gases.” By Dr. L. Bleekrode. Communicated by Dr. Gladstone, F. R. S. Received June 19, 1884. [Publication deferred.]

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EXPERIMENTAL DETERMINATION OF ANTICONVULSIVE ACTIVITY OF CHEMICAL COMPOUNDS

Epilepsia ◽

10.1111/j.1528-1157.1945.tb00669.x ◽

1945 ◽

Vol 3 (1) ◽

pp. 51-75 ◽

Cited By ~ 32

Author(s):

H. Houston Merritt ◽

Tracy J. Putnam

Keyword(s):

Experimental Determination ◽

Chemical Compounds ◽

Anticonvulsive Activity

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IX. On some hitherto undescribed optical properties of doubly refracting crystals.—Preliminary notice

Proceedings of the Royal Society of London ◽

10.1098/rspl.1877.0059 ◽

1878 ◽

Vol 26 (179-184) ◽

pp. 384-386 ◽

Cited By ~ 1

Keyword(s):

Royal Society ◽

Focal Point ◽

The Body ◽

Index Of Refraction ◽

Double Refraction ◽

Other Substances ◽

The Subject ◽

Microscopical Society ◽

Royal Microscopical Society

In the Proceedings of the Royal Society (vol. xxiv. p. 393) Dr Royston-Pigott described a new refractometer to determine the index of refraction of liquids and other substances by means of the displacement of the focal point of an object seen through them with a low magnifying-power. Another paper on the subject was communicated by him to the Royal Microscopical Society, and subsequently published its Journal. After the reading of this paper I said that it appeared me probable that the same principle might be applied with advantage the determination of the index of refraction of minerals. The chief question was how to make the requisite measurements by means of such a addition to an ordinary microscope as would not in any way interfere with its general use for other purposes. This I accomplished by fixing graduated scale to the body of the microscope and a vernier to the supporting arm, so that the position of the focal point can be read off to within about 1/2000 of an inch. I described this arrangement and pointed out its value in connexion with mineralogy at a meeting of the Mineralogical Society last March, and an account of it was published in the Journal of the Society. I have since learned that a very similar addition was made to a microscope in Professor Clifton’s laboratory at Oxford some eight years ago, and used for the measurement of the index of refraction of glass, but no account of it was ever published. When I came to study the index of refraction of doubly refracting minerals I was very soon struck with the fact that, instead of seeing at one focus the two systems of lines at right angles to each other, they were sometimes quite invisible, or one set was seen at one focus, and the whether at a very different, as though they had been ruled on the two opposite sides of a piece of glass. These curious phenomena were exhibited at the soirée of the Royal Society on the 25th of April last, and Processor Stokes immediately examined the question theoretically, and found that they could be explained by, and might have been predicted from, the known laws of double refraction, though apparently no one had ever studied them, either theoretically or practically. We therefore decided to investigate the problem independently. I was to make the practical observations, and he to give the theoretical explanations, the results being kept separate, but communicated conjointly to the Royal Society.

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XXIX. On the Refractive Power of the Two New Fluids in Minerals, with Additional Observations on the Nature and Properties of these Substances

Transactions of the Royal Society of Edinburgh ◽

10.1017/s0080456800024431 ◽

1826 ◽

Vol 10 (2) ◽

pp. 407-427 ◽

Cited By ~ 3

Author(s):

David Brewster

Keyword(s):

Index Of Refraction ◽

Two Fluids ◽

Refractive Power

In the Paper which I had the honour of submitting to the Society, on the Two New Fluids in mineral bodies, I have given the index of refraction for the most expansible of the two, as it exists in the cavities of Amethyst; but as I had not then ascertained the refractive power of the second fluid, and as the principal phenomena of the two fluids, especially those which related to their properties when taken out of the cavities, were observed in specimens of Topaz, it became desirable to have an approximate measure of the refractive power of both of them, as they exist in that mineral. As the fluid in Amethyst had never been examined in the open air, its identity with that in Topaz was inferred solely from the equality of their expansion by heat, so that the determination of the refractive power of the latter was necessary to establish either a difference between these two substances, or their perfect identity.

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An experimental determination of the critical electron velocities for the production of radiation and ionisation on collision with argon atoms

Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character ◽

10.1098/rspa.1920.0011 ◽

1920 ◽

Vol 97 (681) ◽

pp. 1-23 ◽

Cited By ~ 14

Keyword(s):

Experimental Determination ◽

Electric Current ◽

Circular Hole ◽

Royal Society ◽

Tungsten Filament ◽

Electron Collisions ◽

Similar Investigation ◽

Helium Atoms ◽

Electric Effect

In the ‘Proceedings of the Royal Society’ for 1919 (A, vol. 95, p. 408) we have given an account of an investigation of the effects of electron collisions with helium atoms. The apparatus and method there described have been somewhat modified, and applied to a similar investigation with argon. With this gas Franck and Hertz came to the conclusion that ionisation occurs when the velocity of the colliding electrons is raised to 12 volts, but the method of experimenting used by them was not able to distinguish between ionisation of the gas and the photo-electric effect of radiation produced by the collisions. The main features of the apparatus used in the present research have been described in the earlier paper; the modifications introduced will be seen by reference to the diagrammatic view in fig. 1. A short tungsten filament, F, which could be heated to incandescence by an electric current, was used as the source of electrons. This was supported horizontally and about 1·5 mm. below the top of the platinum thimble, E, which was plane and circular, and had at its centre a circular hole 1·5 mm. in diameter.

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