598 



BELL SYSTEM TECHNICAL JOURNAL 



reason some inconsistencies in the data and non-uniformity in the 

 curves might be expected, particularly when plotted to such a large 

 scale as used in these graphs. In Reports and Memoranda of the 

 National Physical Laboratories ^ it appeared from their results that 

 this force was not only small but fairly constant. The results of the 

 tests reported here indicate that while the force is low in magnitude, it 

 varies with the obliquity and the velocity of the wind and the diameter 



o.ooe 



30 40 50 60 

 ANGLE OC IN DEGREES 



Fig. 7 — Graphic relation between the wind force along the wire (tangential-7^,) and 

 the angle (a) of wind direction from normal — 0.104-inch diameter wire. 



of the wire. In the case of 0. 104-inch wire it increases from zero until the 

 angle a (between the wind and the normal to the wire) is about 50° and 

 then decreases as this angle increases. The action is similar in the case 

 of 0.165-inch wire except the maximum is reached when a is about 60°. 

 Whether this shift in the maximum with the wire diameter is real, and 

 how far it would continue, is not clear since only two diameters of 

 wire were tested. For 0.104-inch wire the variation in the force with 



