In detail, he mentions he never heard any sound that could be unequivocally considered as originating in the Aurora, although he had had an opportunity of observing that phenomenon for upwards of 200 nights (the Aurora was registered at Bear Lake 343 times without any sound being heard to attend its motions); but the uniform testimony of the natives and all the older residents in the country induced him to believe that its motions were sometimes audible. On the 11th March, at 10 P.M., a body of Aurora rose N.N.W.; and after a mass had passed E. by S., the remainder broke away in portions, which crossed about 40° of the sky with great rapidity. A hissing noise, like that of a bullet passing through the air, was heard, which seemed to proceed from the Aurora; but Mr. Wentzel assured the party the noise was occasioned by severe cold succeeding mild weather, and acting upon the surface of the snow previously melted in the sun’s rays. A similar noise was heard the next morning. [Sidenote: Capt. Sabine also negatives noise.] In Parry’s first voyage, Captain Sabine describes an Aurora seen at Melville Island, and adds that the Aurora had the appearance of being _very near_ the party, but _no sound could be heard_. [Sidenote: Article “Aurora Polaris,” Encyc. Brit., suggests noises as not improbable.] In the article “Aurora Polaris,” Encyc. Brit, edition ix., the writer admits the evidence of scientific Arctic voyagers having listened in vain for such noises; but, referring to the statements of Greenlanders and others on the subject, concludes there is no _à priori_ improbability of such sounds being occasionally heard, since a somewhat similar sound accompanies the brush-discharge of the electric machine. [Sidenote: Payer negatives and discredits noises.] Payer, of the Austrian Polar Expedition (1872-1874), states that the Aurora was never accompanied by noise, and discredits the alleged accounts of noises in the Shetlands and Siberia. [Sidenote: As also Weyprecht.] Lieut. Weyprecht, of the same expedition, says (_antè_, p. 14):—“Involuntarily we listen; such a spectacle must, we think, be accompanied with sound, but unbroken silence prevails, not the least sound strikes on the ear.” [Sidenote: Herr Carl Bock negatives noises in the case of Lapland Auroræ.] Herr Carl Bock, who accompanied the Laplanders visiting this country (at the Westminster Aquarium) in 1877-78, and who witnessed many brilliant auroral displays in Lapland, assured me he could trace no noise, except on one occasion, when he heard a sort of rustling, which he attributed to the wind. The Laplanders themselves did not associate any special noise with the Aurora. [Sidenote: Auroral noises in telephone. Ringing sound in vacuum-tube under influence of magnet.]