Popular Science Monthly 



677 



In the center is a tendril showing the windings in two directions and the hook in 

 the center. At sides the principle is illustrated with a strip of paper over a pencil 



Why the Tendrils of a Plant 

 Grow in Two Directions 



WHEN a climbing plant has attained 

 such a height that . its weight will 

 prevent it from growing upward it begins 

 to throw out tendrils which grasp other 

 bodies for the purpose of support. 



Somehow the plant knows where a 

 neighboring object is to be found and 

 throws out tendrils in that direction. At 

 first the tendril is straight, but as the 

 object to be grasped is approached a little 

 hook is formed to act as a catch. The 

 moment this has been accomplished the 

 tendril begins to coil up, going first from 

 right to left, then forming a loop and going 

 from left to right. 



Such a tendril is so elastic that there is 

 little danger of its snapping off 

 when the vine is subjected 

 the sudden strain imposed b) 

 the alighting of a bird or 

 the blowing of a sudden 

 gust of wind. 



But why should the 

 tendril grow in two 

 directions? This is a 

 question which has 

 puzzled many. It is 

 answered in the illus- 

 tration above. 



In the center of the 

 illustration is a photo- 

 graph of a tendril, 

 showing the two coils 

 in opposite directions and 

 the loop between them. 

 Now let us take a narrow 

 paper ribbon and coil this 

 around a pencil as at the 



left of the illustration, meanwhile holding the 

 unwrapped portion firmly between the fin- 

 gers. For ever>- turn we make around the 

 pencil, the other portion of the ribbon will 

 make a corresponding twist. If we were to 

 continue the process the twist would finally 

 become so tight that the paper would tear. 

 If we make a loop in the ribbon, as at right 

 of illustration, and wrap the ribbon in the 

 opposite direction on the pencil it will be 

 seen that the twist is uncoiled. This is 

 the principle involved in the growth of 

 the tendril. — Lehmanx Wendell. 



A Switchboard Operator Finds 

 Time to Embroider 



THE accompanying illustration shows 

 how a busy telephone girl proves 

 the truth of the old 

 'Where there's a will 

 way." She has 

 clamp attached 



axiom, 



there's 



had a 



to the 



She is attending strictly to business 

 and embroidering at the same time 



edge of her switchboard, 

 to which is fastened a 

 hooked ring to hold 

 her embroidery 

 frame. She has only 

 to make her connec- 

 tions when a call is 

 received, and then 

 her hands are free. 

 She can talk through 

 the mouthpiece while 

 her hands are busy with 

 the needle. In this way she 

 not only fills her "hope 

 chest" without wasting her 

 employer's time, but she re- 

 lieves the tedium ot the 

 hours and the nerve strain. 



