Vibrations of Solid Bodies. 129 
the bar or plate. As an example, I give the result of two 
rough experiments, which would have been rendered more 
accurate by the aid of an assistant. 
e cord, one meter in length, was brought into unison with 
an Ut, fork, and hence executed 64 double vibrations per sec- 
ond. It was afterward combined with a plate of glass 330 
millimeters long and supported at the two nodes. Five deter- 
minations with the bridge were made, and after bringing the 
cord a second time into unison with the fork, repeated. 
847° 843 
846°9 846°5 
847°7 846°9 
847°1 845°7 
847°7 843 
847°28 845°02 
The result then in the first case was 75'535, in the second 
75-738 vibrations per second. 
n experiment with another piece of glass cut from the 
same plate and of nearly the same length gave, with two deter- 
minations, 77°811 and 77-717 vibrations per second. 
tions per second. The bridge was adjusted till the string was 
an octave lower than the bell-glass when sounding its funda- 
mental note. The results are given below: 
802° 803 
802°7 803°5 
804°5 804 
804°2 801°7 
803°5 802°2 
803°38 802°88 
' The number of vibrations obtained in first case then was 
23899, in the second 239:14, with a difference of ‘15 of a single 
vibration. 
In experiments of this kind it is plain that the pasar 
attainable depends to a great extent on the time during whic 
the vibration of the two bodies can be maintained; still it is 
not admissible to maintain the cord in vibration by the help of 
the bow, as the slightest variation in the pressure causes the 
Am. Jour. Sct.—Turrp Serres, Vou. VIII, No. 44.—Aue., 1874. 
9 
