236 ROUND THE YEAR 



mingles with my recollections of the innocent little 

 peaks of our familiar Lake-country. On Dec. 31, 

 1893, in the height of his manly strength, and in the 

 full enjoyment of his great gifts as an investigator and 

 a teacher, Arthur Milnes Marshall fell from near the 

 summit of Scawfell, and perished in a moment. 



THE REVERSED SPIRAL. 



The tendrils of the Red Bryony in our hedges or 

 of the Passion-flower in greenhouses have been often 

 admired by the readers of Darwin. When our eyes 

 have been opened by the penetrating observations of 

 the great naturalist, it is easy to appreciate the effec- 

 tiveness of the slight but powerful attachments by 

 which the tendril-bearer draws itself up to its support. 

 An unattached tendril, when it contracts, forms a 

 spiral running in one direction from base to apex. 

 But a tendril which has grasped a fixed object be- 

 comes wound from right to left in one part of its 

 length, and from left to right in the remainder, a short 

 straight portion uniting the two spirals (fig. 60). 

 Darwin points out that the spiral spring gives great 

 elasticity to the tendril, a valuable quality in stormy 

 weather. The Bryony rides out the gale with a long 

 range of cable paid out. But why is the spiral re- 

 versed? Darwin explains that every turn in the 

 spiral twists the tendril once. Thirty turns in the 

 same direction would twist the tendril thirty times in 

 succession. No tendril of ordinary length could stand 

 so much twisting ; it would inevitably snap across. 



