The Life of the Spider 



the angle of intersection. Both of them are 

 logarithmic spirals. I see no mechanism of 

 the legs, be they long or short, that can ac- 

 count for this alteration. 



Can it then be a premeditated design on 

 the part of the Epeira ? Can there be calcula- 

 tion, measurement of angles, gauging of the 

 parallel by means of the eye or otherwise? I 

 am inclined to think that there is none of all 

 this, or at least nothing but an innate pro- 

 pensity, whose effects the animal is no more 

 able to control than the flower is able to con- 

 trol the arrangement of its verticils. The 

 Epeira practises higher geometry without 

 knowing or caring. The thing works of itself 

 and takes its impetus from an instinct im- 

 posed upon creation from the start. 



The stone thrown by the hand returns to 

 earth describing a certain curve; the dead leaf 

 torn and wafted away by a breath of wind 

 makes its journey from the tree to the ground 

 with a similar curve. On neither the one side 

 nor the other is there any action by the mov- 

 ing body to regulate the fall ; nevertheless, the 

 descent takes place according to a scientific 

 trajectory, the 'parabola,' of which the section 

 of a cone by a plane furnished the prototype 



396 



