Abstract
Poggendorff's Annalen der Physik und Chemie, 1875, No. I. This number contains the following papers:—On the electric conducting power of solutions of the chlorides of alkalies and alkaline earths, and of nitric acid, by F. Kohlrausch and O. Grotrian.—On the gliding of electric sparks, by K. Antolik. The author published his first paper on this subject at the beginning of last year, and has since then been gaining much new experience on the subject; he had observed long ago that if the two discharge balls of a Holz electric machine are at a certain small distance from each other, the path of the spark is not in a zigzag line, but straight, and that the spark is often strongly bent or broken in a certain point, which lies nearer the negative pole. Mr. Antolik's idea was that negative electricity leaves bodies somewhat slower than positive electricity, and that the bending point in the spark was the place where the two electricities united. He successfully tried to obtain an image of the spark by letting it pass over a blackened glass bulb; thus he found that the spark glides in three and often five parallel lines. The paper is very elaborate and highly interesting, the author having varied his experiments in all possible ways.—On a universal meteorograph for solitary observatories, by E. H. von. Baumhauer. The Dutch Scientific Society of Haarlem offered its gold medal and a purse of 300 florins in January 1872, for a sufficient means to determine temperature, density, and degree of moisture of the atmosphere at a considerable elevation above the surface of the earth, and in a manner which makes self-registration and constant repetition of observations possible. Herr Baumhauer's paper enters into the details of this problem and describes certain instruments which the author devised, and which go far to solve the question at stake, although certain modifications of the Society's demand became necessary, there being a great difference when the term “at a considerable elevation” is applied to a spot which is comparatively easy of access at any time, or when, for instance, it denotes a captive balloon. The author, however, describes instruments which would answer very well in both cases.—Continuation of researches on rod magnetism, by A. L. Holz (see vol. 151, p. 69 of these Annals).—On the measuring of angles by means of the eyepiece micrometer in astronomical telescopes, by Dr. Matern.—On the proportion of specific heats under constant pressures and in constant volumes, by J. J. Müller.—On some observations of the spectra of gases, by Eugen Goldstein. The author has made a series of experiments which tend to show that Wüllner's idea as to the independence of the gas spectra from differences in the temperature is an erroneous one. They principally consist in interpoisng a layer of air into the induction current, which lights up the spectral tubes filled with the rarefied gases, sometimes with a simultaneous insertion of a Leyden jar, and thus forcing the current to produce a spark. Mr. Goldstein then shows that in the whole circle of the current the discharge takes place in the same rhythm, therefore that the current passes the tube filled with the rarefied gas just as momentarily as any other part of the circle; from this he concludes that also in the tube the discharge takes place in form of a spark, that therefore the gas ought to show a line spectrum. Now, as this is not the case, and the gas on the contrary shows a band spectrum, the author thinks this a contradiction of Wüllner's explanation.—The next paper in the number is by Herr Wüllner himself, and explains the subject very satisfactorily, as he proves that not one of Herr Goldstein's experiments is contradictory to his theory of the different spectra of gases; the form of the electric discharge in the tubes containing the gases is the main point in question, and Herr Wüllner proves this to be in the so-called dilated form, and not as a spark.—Finally, the number contains a preliminary report by Dr. V. Dvorak, on the velocity of sound travelling in water.
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Scientific Serials . Nature 11, 518 (1875). https://doi.org/10.1038/011518a0
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DOI: https://doi.org/10.1038/011518a0