SPIDERS. 257 



steeple of York Minster, from whence he could dis- 

 cern the floating webs still very high above him. 

 Some spiders that fell and were entangled upon the 

 pinnacle he took. They were of a kind that never 

 enter houses, and therefore could not be supposed to 

 take their flight from the steeple. From his observa- 

 tions it is clear that he did not consider this faculty 

 to be confined to one species of spider, but common 

 to several, though only in their half-grown state. Of 

 one, he says, certainly this is an excellent rope-dancer, 

 and is wonderfully delighted with darting its threads ; 

 nor is it only carried in the air, but it effects itself its 

 ascent and sailing ; for by means of its legs closely 

 applied to each other it as it were balances itself, and 

 promotes and directs its course no otherwise than as if 

 nature had furnished it with wings or oars. 



Mr. Blackwell gives a summary of the facts as far 

 as they are known : " Although spiders," he says, 

 "are not provided with wings, and consequently are 

 incapable of flying in the strict sense of the word, 

 yet by the aid of their silken filaments numerous 

 species belonging to various genera are enabled to 

 accomplish distant journeys through the atmosphere. 

 These aerial excursions, which appear to result from 

 an instinctive desire to migrate, are undertaken when 

 the weather is bright and serene, particularly in 

 autumn, both by adult and immature individuals, and 

 are effected in the following manner. After climb- 

 ing to the summits of different objects, they raise 

 themselves still higher by straightening the limbs ; then 

 elevating the abdomen by bringing it from the usual 

 horizontal position into one almost perpendicular, they 



