ENGINEERING SKILL OF SPIDERS. 217 



the distance of the web (counterpoise?) from the ground was about a 

 metre and a half, which would seem to preclude the theory that it had 

 been raised up from the ground by the elasticity of the web, or the 

 mechanical impact of the wind. 



Nevertheless, I am constrained to believe that in this case also the 

 explanation of intentional engineering must be dismissed. The pellet 

 had evidently been separated from the vault by the erosion 

 ^ ie of the atmosphere, and had either been lifted up from the 



u orij ground, where it had fallen, in the manner I have described, 

 or, which is more probable, it had entangled within the web 

 as it fell; had been prevented by the foundation cords from dropping 

 entirely to the ground; had been held above the surface by the viscidity 

 and natural elasticity of the threads ; and while thus hanging, accidentally 

 poised, it was made use of by the spider as a point from which to re- 

 attach her foundation line. As long as it remained in poise, undisturbed 

 by the wind or passing objects, it would be available for the purpose 

 of staying her web ; and in this position it was the fortune of Professor 

 Parona to see it. 



However this theory may accord with the facts, I am perfectly assured 

 that the spider could not have cut off from the vault a particle of soil so 

 large, and then have transferred it to the position where it was seen. 

 Such action is so wholly foreign from all that I have observed of the 

 habits of Orbweavers, that I cannot possibly allow myself to admit it as a 

 reasonable explanation. On the whole, my judgment is that none of the 

 instances heretofore observed, in the form at least in which they are re- 

 corded, afford sufficient testimony to permit us to believe that Orbweavers 

 have the engineering ability to counterpoise their webs against the action 

 of wind and the natural shrinkage of the web material, by means of peb- 

 bles or other objects attached to marginal lines. 



Indeed, if such action were really proved, it would seem to me an un- 

 wise and not a cunning exception to the general habit in like web sites, 

 which is to carry the principal supporting line quite down to the firm 

 earth. Nothing could be gained, and much would be lost, by exchanging 

 this for an unstable counterpoise. Would the spider be apt to pause 

 within an inch or two of the ground, which was thus clearly within its 

 reach, to make so unprofitable an exchange? The only special 

 Counter- w i^ om that can be allowed the spider in the case is that 

 3e l which accepts an undesirable situation as at least available, and 



adapts her spinningwork thereto ; and that is certainly to be rec- 

 ognized, and it is sufficiently remarkable. 



II. 



It is not to be doubted that spiders do show considerable powers of 

 adaptation in adjusting their spinningwork both to peculiar situations and 



