Abstract
American Journal of Science, December.—Inversion of temperatures in the 26˙68 day solar magnetic period, by Frank H. Bigelow. The northern low-pressure and the southern high-pressure belts of North America vary in latitude directly with the solar magnetic intensity, being further north at the maximum and further south at the minimum of the period; whilst the northern high and southern low-pressure belts vary in the opposite manner. This means that an increase of solar magnetic intensity generates the cyclones further south, and causes the anti-cyclones from the polar circulation to travel to the south.—Remarks on colloidal silver, by C. Barus. Colloidal silver possesses properties which can be explained with reference to the analogous behaviour of suspended sediments, allowance being made for differences in the size of particles. The high degree of insulation detected in Carey Lea's metallic mirrors may be interpreted as an instance of the altered behaviour of non-coherent metallic matter.—Resonance analysis of alternating currents, by M. I. Pupin. Part ii. Closed magnetic circuit transformers distort the primary current considerably more than transformers with open magnetic circuits under equal degrees of magnetisation. A ferric self-inductance in circuit with an alternator which gives a simple harmonic E.M.F. distorts the current by introducing higher odd harmonics, principally the harmonic of three times the frequency of the fundamental. Rotary magnetic fields produced by reasonably well-constructed machines are not accompanied by fluctuations in their intensity.—An improved form of interruptor for large induction coils, by F. L. O. Wadsworth. The interruptor consists of a brass wheel about six inches in diameter, with two insulating and two contact segments placed in its circumference, and mounted directly on the shaft of a small electric motor making about 1200 revolutions per minute. Two copper brushes are made to bear on the hub of the wheel and its circumference respectively. The hub and the conducting sectors are in one piece. The insulators are made of slate.
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Scientific Serials. Nature 51, 190 (1894). https://doi.org/10.1038/051190a0
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DOI: https://doi.org/10.1038/051190a0