128 M. C. Ihlseng— Velocity of Sound in Wood. 
long and 19™™ internal diameter; the cork H, inclusive of 
1-08 grams. 
The probable error is so small that it would seem to indicate 
either that the procedure is a very accurate one or that the 
The apparatus was capable of being leveled accurately, and it 
e 
result, of course, is that two parallel sets of curves are traced 
on the smoked glass. For the purpose of making the measure- 
3°57 3°58 
3°60 3°55 
3°58 3°42 
3°70 3°30 
3°52 ee 
3°75 3°56 
For determining the rate of the fork, the average of six 
determinations of 5-033 seconds each, by a chronograph, was 
taken as follows: diene = 25504 
* 65-033 : 
The difference between this quantity and the number of 
vibrations stamped on the fork by Koenig (256) was due to the 
fact that the fork was loaded by the wax and pointer. 
