126 M. C. Ihlseng— Velocity of Sound in Wood. 
‘ployed a method of this kind, and connected with the roda 
chronographic apparatus. He determined the transverse vibra- 
tions of the rod by simultaneously registering those of a tuning 
fork, and then superimposed the longitudinal vibrations of the 
rod upon its transverse, and ascertained from the corruga 
wave line thus produced, the relation between the longitudinal 
and transverse vibrations. 
undt,* however, in 1866 contrived a method which is so 
well known as to need only a few words of description. A 
organ pipes, the ratio of the length of the wave in the petra: 
heat under a constant volume to the specific heat under a con- 
stant pressure. 
All of the above experiments were made upon metals. With 
the exception of MM. Wertheim and Chevandier’s extended 
researches{ upon the woods of the Vosga forests, I know per 
American woods, Kundt’s method was first employed; he 
apparatus was similar to his but somewhat modified to suit the 
2. 
: He? 
| | | 
ae ae | I 
special circumstances. Fig. 1 shows the arrangement 10 per 
spective; B is the vise holding the rod, AC, clamped by a screw; 
O, acting on a plate of brass which presses the rod firmly oes 
its rest; the vise is screwed upon “a table, which is fasten 
to the floor and braced to avoid shaking. e rod is r ubl 
by a resined woolen cloth along A, and being set into vibration, 
* Pogg. Ann., exxvii, 337. + Ibid., 1877, N. 10, p. 218. 
¢ Comptes Rendus, xxiii, 663. 
