in.] ORGANIC STABILITY, 21 



likings of each, individual insect in a flying swarm may 

 be supposed to determine the position that he occupies 

 in it. Every particle must have many immediate neigh- 

 bours. Even a sphere surrounded by other spheres of 

 equal sizes, like a cannon-ball in the middle of a heap, 

 when they are piled in the most compact form, is in 

 actual contact with no less than twelve others. We may 

 therefore feel assured that the particles which are still 

 unfixed must be affected by very numerous influences 

 acting from all sides and varying with slight changes of 

 place, and that they may occupy many positions of tem- 

 porary and unsteady equilibrium, and be subject to 

 repeated unsettlement, before they finally assume the 

 positions in which they severally remain at rest. 



The whimsical effects of chance in producing stable 

 results are common enough. Tangled strings variously 

 twitched, soon get themselves into tight knots. Rub- 

 bish thrown down a sink is pretty sure in time to choke 

 the pipe ; no one bit may be so large as its bore, but 

 several bits in their numerous chance encounters will 

 at length so come into collision as to wedge themselves 

 into a sort of arch across the tube, and effectually plug 

 it. Many years ago there was a fall of large stones from 

 the ruinous walls of Kenilworth Castle. Three of them, 

 if I recollect rightly, or possibly four, fell into a very 

 peculiar arrangement, and bridged the interval between 

 the jambs of an old window. There they stuck fast, 

 showing clearly against the sky. The oddity of the 

 structure attracted continual attention, and its stability 

 was much commented on. These hanging stones, as 



