MOTION OF TELEPHONE WIRES IN WIND 363 



results are shown in Fig. S-B for a span of 200'. Both indicate the 

 marked increase of sag under not uncommon wind conditions. 



While the above formula and charts give a fairly definite picture of 

 the effect of elasticity on the solution of the problem of static equili- 

 brium, the much more complex problem of the motion of an elastic 

 loop in a varying wind has not been attacked.^ The necessity for such 

 additional refinements can probably not be determined until the field 

 experiments above referred to have progressed to the point where 

 fairly comprehensive data are available for analysis and for a check 

 of the theoretical conclusions arrived at in this paper. 



* An article by Karl Wolf in Zeitschrift f iir Angewandte Mathematik und Mechanik 

 of April 1927 treats certain aspects of the dynamics of an elastic loop, with particular 

 reference, however, to power lines. As yet, no attempt has been made to apply the 

 results of this work to our particular problems. 



