G. S. Moler — Transverse Vibrations of Cords and Wires. 341 



Table. 



Observa- 

 tion. 



Cross 

 Section. 



S. 



Length. 

 L. 



Rate of 

 Vibra- 

 tion. 



N. 



Number 



of 

 Segment. 



Tension 

 Gram 

 P. 



Square 

 i n root of 



3 - Tension. 



V¥ 



Constant 

 NL sd 



No. 1 



fd 



1 



2 



1 



627 



25-04 



12-52 



" 2 



a 



1 



2 



2 



162 



12-70 



12-70 



" 3 





1 



2 



3 



74 



8-60 



12-90 



" 4 





1 



2 



4 



41 



6-40 



12-80 



" 5 





1 



2 



5 



26 



5-10 



12-75 



No. 6 



^6 



1 



2 



1 



627 



25-04 



12-52 



u 7 



Pi 



1 



2 



1 



266 



16.30 



12-22 



8 



03 



* 



2 



1 



166 



12-90 



12-90 



No. 9 





1 



2 



1 



• 2500 



50-00 



12-50 



" 10 



T3 



1 



, 2 



2 



625 



20-00 



12-50 



" 11 



^ S 



1 



2 



3 



280 



16-70 



12-52 



" 12 



CO 



1 



2 



4 



158 



12-60 



1260 



No. 13 



rd 



1 



1 



1 



166 



12-90 



1290 



" 14 



1 



1 



1 



2 



41 



6-40 



12-80 



" 15 



■+J 



1 



1 



3 



18 



4-20 



12-60 



" 16 



^ 



1 



1 



4 



9 



•5 3-10 



1 12-40 



visible. By interposing a long narrow slit between the cord 

 and a strong light, a single point may be illuminated, which 

 when the cord is in motion, traces in the most beautiful man- 

 ner, by persistence of vision, the path of that portion of the 

 vibrating segment. By the use of a series "of parallel slits any 

 number of such illuminated paths may be made visible at 

 once, bringing out the character of vibration of the entire 

 segment with an indescribably striking effect. The curves 

 followed by the illuminated points are Lissajou's figures and 

 kindred forms. The regulation attained by means of the con- 

 trolling cord is so excellent that it was found possible to photo- 

 graph the curves with an ordinary dry plate. During an ex- 

 posure of three minutes the changes in the form, size and 

 position of the illuminated cross- section of the vibrating seg- 

 ment were not such as to ruin the picture. 



The behavior of the vibrating cord as a controlling device is 

 such that it seems possible to use it to advantage as a means of 

 obtaining a uniform motion in chronographs and similar instru- 

 ments. Its length or tension could be adjusted without stop- 

 ping the apparatus and any desired rate of speed could be thus 

 obtained without interrupting the work which might be in 

 progress. 



June 2, 1888. 



