THE REASON WHY. 



273 



1 The spider taketh hold with her hands, and is in king's palaces." 

 PROVERBS xxx. 



whether she enters or goes out, says Mr. Kirby, the door shuts of itself. But 

 the water-spider has a domicile more curious still : it is under water, with an 

 opening at the lower part for her exit and entrance ; and although this cell ba 

 under water, it contains air like a diving-bell, so that the spider breathes the 

 atmosphere. The air is renewed in the cell in a manner not easily explained. 

 The spider comes to the surface ; a bubble of air is attracted to its body ; with 

 this air she descends, and gets under her cell, when the air is disengaged and 

 rises into the cell ; and thus, though under water, she lives in the air. There 

 must be some peculiar property of the surface of this creature by which she can 

 move in the water surrounded with an atmosphere, and live under the water 

 breathing the air. 



Fig. 72. WEB O* THE GEOMETRICAL SPIDER. 



The chief instrument by which the spider performs these wonders is the 

 spinning apparatus. The matter from which the threads are spun is the liquid 

 contained in cells ; the ducts from these cells open upon little projecting teats, 

 and the atmosphere has so immediate an effect upon this liquid, that upon 

 exposure to it the secretion becomes a tough and strong thread. Twenty- four 

 of these fine strands form together a thread of the thickness of that of the 

 silk-worm. We are assured that there are three different sorts of material thus 

 produced, which are indeed required for the various purposes to which the 



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