586 Mr. C. A. B. Garrett on the 
can be repeated. To find the required displacements for the 
dynamical curve we proceed thus :— 
The bar is set in vibration by holding it up to the block A 
(fig. 6) and then releasing. We are guided by the photographs 
to set A so as to touch the bar one-fifth of the way down. 
The position of A is adjusted until the bar comes up to the 
cross-wire in M, at (say) the 20th swing. M, is then run 
along until the bar comes up to its cross-wire after the same 
number of swings; the reading of M, is taken. The bar is 
now held aside in such a position that the top is again on the 
cross-wire of M,. M, is again set on the bar and the reading 
taken. In the latter case we may apply the bending force 
at any point along the bar, and the reading of M, will be 
different in each case. 
In this way we make the displacement of the end the same 
for all cases, while that of the middle varies with the con- 
ditions, and may be regarded for our purpose as the charac- 
‘teristic of a given curve. Three distinct sets of readings are 
given below (p. 587). In each case the displacement of the 
end of the bar is 7°68 cms. 
We see from these results that the two curves would 
coincide at the middle and the two ends, if the force were 
applied at a point on the bar distant ‘23 of the length from 
the free end. 
