MOTIONS OF INSECTS. 



275 



circuitously, and with less labour, than if they had travelled 

 over the ground. As these creatures seem so thirsty, may 

 we not conjecture that the drops of dew, with which they are 

 always as it were strung, are a secondary object with them ? 

 So prodigious are their numbers, that sometimes every stalk 

 of straw in the stubbles, and every clod and stone in the 

 fallows, swarms with them. Dr. Strack assures us that 

 twenty or thirty often sit upon a single straw, and that he 

 collected about 2000 in half an hour, and could have easily 

 doubled the number had he wished it : he remarks, that the 

 cause of their escaping the notice of other observers is their 

 falling to the ground upon the least alarm. 



As to what becomes of this immense carpeting of web 

 there are different opinions. Mr. White conjectures that 

 these threads, when first shot, might be entangled in the 

 rising dew, and so drawn up, spiders and all, by a brisk 

 evaporation, into the region where the clouds are formed. 1 

 But this seems almost as inadmissible as that of Hooke, 

 before related. An ingenious and observant friend, thinking 

 the numbers of the flying spiders not sufficient to produce 

 the whole of the phenomenon in question, is of opinion that 

 an equinoctial gale, sweeping along the fallows and stubbles 

 coated with the gossamer, must bring many single threads 

 into contact, which, adhering together, may gradually collect 

 into flakes ; and that being at length detached by the violence 

 of the wind, they are carried along with it : and as it is 

 known that such winds often convey even sand and earth to 

 great heights, he deems it highly probable that so light a 

 substance may be transported to so great an elevation as not 

 to fall to the earth for some days after, when the weather 

 has become serene, or to descend upon ships at sea, as has 

 sometimes happened. This, which is in part adopted from 

 the German authors, is certainly a much more reasonable 

 supposition than the other ; but some facts seem to militate 

 against it : for, in the first place, though gossamer often 

 occurs upon the ground when there is none in the air, yet 

 the reverse of this has never been observed ; for gossamer in 



1 Nat. Hist. i. 326. 

 T 2 



