Sound / by John Tyndall.

  • Tyndall, John, 1820-1893.
Date:
1883
Catalogue details

Licence: Public Domain Mark

Credit: Sound / by John Tyndall. Source: Wellcome Collection.

Provider: This material has been provided by UCL Library Services. The original may be consulted at UCL (University College London)

    62/494 (page 40)
    elasticity discovered by Savart. MM. Wertheim and. Chevandier have determined the velocity of sound along these three axes and obtained the following results: Velocity of Sound in Wood. Name of Wood Acacia . Fir Beech . Oak Pine . Elm Sycamore Ash Alder . Aspen . Maple . Poplar . Along Fibre Across Rings 15,467 4,840 4,382 10,965 6,028 12,622 5,036 10,900 4,611 13,516 4,665 14,639 4,916 4,567 15,306 4,491 16,677 5,297 13,472 5,047 14,050 4,600 4,436 2,572 4,643 4,229 2,605 3,324 3,728 4,142 3,423 2,987 3,401 3,444 Fig. 14. Separating a cube from the bark-wood of a good-sized tree, where the rings for a short distance may be regarded as straight; then if A R, fig. 14, be the section of the tree, the velocity of the sound in the direction m n, through such a cube, is greater than in the direction a b. The foregoing table strik- ingly illustrates the in- fluence of molecular struc- ture. The great majority of crystals show differences of the same kind. Such bodies, for the most part, have their molecules arranged in different degrees of proximity in different directions, and where this occurs there are sure to be differences in the transmission and manifestation of heat, light, electricity, magnetism, and sound.