Abstract
American Journal of Science, January.—Researches in acoustics, No. 9, by Alfred M. Mayer. This paper deals with the law connecting the pitch of a sound with the duration of its residual sensation, and with the smallest consonant intervals among simple tones. The residual sound, i.e. the sound perceived by the ear after the actual vibration has ceased, was investigated by means of an apparatus consisting of a tuning-fork vibrating close to the opening of a resonator. The nipple of the resonator was placed opposite a hearing-tube leading to the ear, and the sound was interrupted by a rotating perforated disc interposed between the nipple and the opening of the tube. The discs, which were made of mahogany covered with cardboard, had several circles of holes, and intercepted the sound very effectively. The discs were worked by a hand-pulley and flywheel, controlled by a clock beating seconds loudly. The residual sensations obtained, by noticing at what speed the sound became continuous, ranged from 0.0231 sees, in the case of Ut2, frequency 128, to 0.0049 sees, in the case of Ut5, frequency 1024. The smallest consonant intervals were determined by noticing when the beats coalesced into a smooth tone. The residual sensations deduced from these experiments were found to be about one-third greater than those obtained by the former method.—Petroleum in its relations to asphaltic pavement, by S. F. Peckham. While it has been well known for years that bitumens occur in great variety, the selection of a proper material for softening the asphalt, to the exclusion of others less desirable or wholly unfit, appears to have escaped attention. A properly selected material should enter into chemical union with both the constituents of the bitumen in the asphalt, thereby increasing its adhesive and binding properties upon the other constituents of the mastic. The proportion of bitumen to sand and other non-bituminous ingredients should be as 1: 9, a larger amount of bitumen making the pavement too soft, and a smaller amount giving too little stability.—The age of the extra-moraine fringe in Eastern Pennsylvania, by E. H. Williams, Junr. All observations tend to the conclusion that there was but one ice age in Pennsylvania, and that a short and recent one.—The internal work of the wind, by S. P. Langley (see Notes).—Post-glacial æolian action in Southern New England, by J. B. Woodworth. This paper treats mainly of the action of blown sand in carving rocks and boulders.
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Scientific Serials. Nature 49, 305–306 (1894). https://doi.org/10.1038/049305a0
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DOI: https://doi.org/10.1038/049305a0