CH. XIV.] THE SPIDER. 239 



last serve as a sort of temporary scaffolding to walk 

 over, and to keep the radii properly stretched while 

 she glues to them the concentric circles that are to 

 remain, which she now proceeds to construct. 

 Placing herself at the circumference, and fastening 

 her thread to the end of one of the radii, she walks 

 up that one, towards the centre,, to such a distance 

 as to draw the thread from her body of a sufficient 

 length to reach to the next. Then stepping across 

 and conducting the thread with one of her hind-feet 

 she glues it with her spinners to the point in the ad 

 joining radius to which it is to be fixed. This pro- 

 cess she repeats until she has filled up nearly the 

 whole space from the circumference to the centre 

 with concentric circles distant from each other about 

 two lines. She always, however, leaves a vacant 

 interval around the smallest first spun circles that 

 are nearest to the centre, but for what end I am 

 unable to conjecture. Lastly, she runs to the cen- 

 tre, and bites away the small cotton-like tuft that 

 united all the radii, which, being now held together 

 by the circular threads, have thus probably their 

 elasticity increased; and in the circular opening 

 resulting from this procedure she takes her station, 

 and watches for her prey." 



The manoeuvres of a spider which wants to 

 escape from any object surrounded by water, are 

 extremely interesting. In his treatise on the Apple 

 and Pear, Mr. Knight states, that if a spider be placed 

 upon an upright stick, having its bottom immersed 

 in water, it will, after trying in vain all other modes 

 of escape, dart out numerous fine threads, so light 

 as to float in the air, some one of which, attach- 

 ing- itself to a neighbouring object, furnishes a 

 bridge for its escape. An experiment, made by 

 Kirby, confirms the truth of this statement. " I 

 placed," says he, " the large field-spider upon a stick, 

 about a foot long, set upright in a vessel containing 

 water. After fastening its thread (as all spiders do 



