ELASTIC PROPERTIES OF DRAWN TUNGSTEN WIRES 209 
will not be discussed except to state that they are uniformly 
smaller than the values determined kinetically, when the periods 
corresponding to the smaller amplitudes were used. 
In some previous experiments, which were reported to the 
American Physical Society, 2 with specimens of wire picked up 
at random, it was found that there seemed to be no regular re- 
lations between the coefficient of rigidity and the radius of the 
wire. In these present experiments, however, a distinct varia- 
tion in n was found, the wires of smallest diameter having the 
largest values for n. The results for the two batches of wire 
Figure 29 
are shown in figure 29. It is to be noted that the wires from 
the two lots are different in that those of one set are uniformly 
more rigid than the others, but that in any one set there is a 
general tendency for n to increase as the radius of the wire de- 
creases. 
Jt is of interest to note the large values of n for these tungsten 
wires. For steel n is about 8.0xl0 1:L dynes per cm 2 , and so it is 
seen that the rigidity of certain of these tungsten wires is over 
100 per cent greater than the most rigid substance hitherto 
known. 
2 Pbys. Rev. IX, p. 337, 1917. 
14 
