Sometimes lathe
A long thin piece of wood.
Ramsay
An elongated uniform body, e.g., a dressed lath of pine, has three primary centers - the center of gravity, the center of oscillation, and the center of velocity. The center of gravity is the center of the body; the center of oscillation is at two-thirds from the end as the point of suspension; the center of velocity is at two-thirds of one-third from the end, i.e., at two-ninths from the end as the point of suspension. [Scientific Basis and Build of Music, page 92]
When a uniform dressed lath is held at the center of gravity and struck, it vibrates freely with a low tremor; when held at the center of velocity and struck at the center of gravity, it vibrates freely, and goes into large sections. But if it be struck at two-thirds of one-third from the other end, its own center of percussion, it has not the least tendency to vibrate. But if it be held at the center of velocity, and at its own center of percussion at the other end, and struck at the center of gravity, these two places will become points of rest, and the lath will move freely in all the other parts. [Scientific Basis and Build of Music, page 93]
Here on the keyboard we see, nearest to the front, the great 3-times-3 chord of the full genesis of the scale from F1 to F64. When this chord is struck by the notched lath represented in front of the keyboard, the whole harmony of the key is heard at once. Behind this great chord are placed, to the left the subdominant, tonic, and dominant chords of the minor. D F A, A E C, E G B; and to the right the subdominant, tonic, and dominant chords of the major, F A C, C E G, G B D. When the notched lath is shifted from F to D, the minor third below F, and the 3-times-3 minor is struck down in the same way as the major, the whole harmony is heard; and the complete contrast of effect between major and minor harmony can be fully pronounced to the ear by this means. Behind these six diatonic chords, major and minor, on the part of the keyboard nearest to the black keys, are the three chromatic chords in their four-foldness, in both major and minor form. The center one shows the diatonic germ of the chromatic chord, with its supplement of G# on the one hand completing its minor form, and its supplement of A? on the other hand completing its major form. A great deal of teaching may be illustrated by this plate.