244 NATURAL HISTORY. [cH. XIV. 



power of drawing this air in at the anus, from the 

 atmosphere at the surface of the pool, but the pre- 

 cise mode in which it is separated from the body of 

 the atmosphere, and introduced under the pellicle 

 covering the insect's body, has not been clearly as- 

 certained. Thus clothed, and shining like a ball of 

 quicksilver, it darts through the waters, to the spot 

 in which it had fixed its habitation, and disengaging 

 the bubble from under the pellicle, it dexterously 

 introduces it into a Aveb formed at the bottom. 

 After repeatedly moving from the top to the bottom 

 of the water, and at each journey filling its habita- 

 tion with a fresh bubble of air, at length the lighter 

 completely expels the heavier fluid, and the insect 

 takes possession of an aerial habitation, commodious 

 and dry, finished in the very midst of the waters. 

 It is about the size and shape of half a pigeon's egg. 

 From this curious chamber the spider hunts, search- 

 ing sometimes the waters, and sometimes the land 

 for its prey, which, when obtained, is transported to 

 this sub-aquatic mansion, and devoured at leisure. 

 The male as well as the female exhibits the same in- 

 stincts. Early in the spring, the former seeks the 

 mansion of the latter, and having enlarged it by the 

 introduction of a little more air, takes up its abode 

 with its mate. About the middle of April, the eggs 

 are laid, and, packed up in a silken cocoon in a cor- 

 ner of their house, are watched with incessant care 

 by the female. 



In modern times, much interest has been excited 

 by the elevation of bodies in the air by means of a 

 balloon. The discovery consisted in finding out a 

 manageable substance which was, bulk for bulk, 

 lighter than air ; and the application of the discovery 

 was to make a body composed of this substance 

 bear up, along with its own weight, some heavier 

 body which was attached to it. This expedient, so 

 new to us, proves to be no other than what the Au- 

 thor of nature has employed in the gossamer spider. 



