116 A NATURALIST IN HIMALAYA 



Thus a spider, during the construction of a circular 

 eccentric snare, may, by its exquisite sense of touch, 

 differentiate between the long and the short radii. It 

 may continue to reverse its spiral so as to attach addi- 

 tional turns to the long radii until sufficient reverses 

 have been made to give the free parts of all the radii 

 an equal length and convey a uniform stimulus to the 

 sense of touch. This speculation is to a great extent 

 surmise. It is supported by the fact that the reversals 

 are more numerous during the earlier turns of the 

 spiral when the inequality of the radii would be more 

 easily felt. In the latter half of the construction the 

 number of the reversals is few or there may be none 

 at all. And this I think is due to the fact that the 

 radii are then less unequal owing to the many reversals 

 already made. 



And if this view be true, then how delicate must be 

 the sense of a spider's touch. It must be developed to 

 so high a degree of perfection that the mathematical 

 accuracy of the work will very largely depend on the 

 delicacy of the tactile power to estimate the changes of 

 tension in the lines of different length that radiate from 

 the centre of an eccentric snare. 



A geometrical spider engaged in architecture pur- 

 sues its work with a restless energy. The bees, when 

 seeking nectar from the flowers; the ants, when storing 

 up provision in their nest, are no more tireless in 

 their toil. It moves with hurried pace along every 

 spoke ; it measures its lines with almost imperceptible 

 touch ; it seals its filament in an instant and then 

 hastens away. All its movements are so agile that at 

 the moment it can have but one object in view, the 

 speedy completion of its snare. 



