214 



IOWA ACADEMY OF SCIENCE 



THE PROBLEM. 



The extensive use of phosphor-bronze wires as delicate sus- 

 pensions, makes it very desirable to know intimately the elastic 

 nature of this alloy. Some work by Professor Sieg and the 

 writer in 1914, showed that the periods of the torsional vibra- 

 tions were not constant but varied widely with different ampli- 

 tudes. 



The problem of this research was the verification of this 

 clastic peculiarity and to prove that there is no justification for 

 the use of these wires as delicate suspensions. New problems 

 suggested themselves at once and some of these have been in- 

 vestigated to find out, if possible, more of the intimate nature 

 of the alloy. 



r^~ 



Fig. 28. 



A preliminary report of certain of these experiments Mas 

 given before the Iowa Academy of Science in the spring of 

 1915*. 



APPARATUS. 



The apparatus is the same one which was employed and de- 

 scribed by Sieg 5 . Figure 27 shows the complete apparatus with 

 the exception of the arc which was used to illuminate the mir- 

 ror, and figure 28 shows the timing device. 



*Iowa Academy of Science, Vol. 22, 1915, p. 321. 

 5 Loc. cit. 



