Sound and the physical basis of music - Softcover

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1877 Excerpt: ... waves, the whole string will divide itself into vibrating parts separated by points of no vibration. 51. Nodes and Ventral Segments.--These parts ON, OP, &c., are usually termed ventral segments; and the stationary Fig. 23 points O, P, &c., are called nodes; the number of nodes is of course one less than the number of ventral segments; and the latter number is a measure of the rate of vibration. When a string divides into two, three, four, &c. ventral segments, it is vibrating at two, three, four, &c. times the rate of its fundamental vibration. This, then, is the complete explanation of the experiment referred to in sect. 6, as illustrating the conversion of backand-fore pulsations into up-and-down waves. It is due to M. Melde of Marburg in Germany, and is an exceedingly instructive as well as exquisitely beautiful experiment. The prong of the tuning-fork takes the place of the hand as a more perfect governor of the jerks, and the result is a symmetry in the division of the string which could not be equalled by any other means. Tiny pieces of reflecting bead glued to the string we have found very suitable for illuminating the path of the vibrating string, which, in the words of Professor Tyndall, is sometimes 'of marvellous complication and indescribable splendour.' 52. Spontaneous Subdivision of a Musical String.--In a musical string stretched tightly between its two ends, the conditions are very much the same as in the cases just described. With the hand and spiral cord we have the means of varying the governing vibrator and the tension at pleasure; with a single tuning-fork and white silk string, in Melde's experiment (sect. 6 and fig. 5), the number of ventral segments can be varied only by changing the tension of the string. But in th...