SPIDERS. 339 



lets in one of its threads, calculated that it would 

 require four millions of them to be as thick as a hair 

 of his heard. 



Another important advantage derived by the spider 

 from the multiplicity of its threadlets is, that the thread 

 affords a much more secure attachment to a wall, 

 a branch of a tree, or any other object, than if it were 

 simple; for, upon pressing the spinneret against the 

 object, as spiders always do when they fix a thread, 

 the spinnerules are extended over an area of some 

 diameter, from every hair's breadth of which a strand, 

 as rope-makers term it, is extended to compound the 

 main cord. The following figure exhibits this inge- 

 nious contrivance. 



Attached end of a Spidtr's thread magnified. 



Those who may be curious to examine this contri- 

 vance will see it best when the line is attached to 

 any black object; for the threads being white are, in 

 other cases not so easily perceived. 



Shooting of the Lines. 



It has long been considered a curious, though a 

 difficult investigation, to determine in what manner 



