MOTIOXS OF INSECTS. 343, 



convey even sand and earth to great heights, he deems it 

 highly probable that so light a substance may be trans- 

 ported to so great an elevation, as not to fall to the earth 

 for some days after, when the weather has become se- 

 rene, or to descend upon ships at sea, as has sometimes 

 happened. This, which is in part accepted 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 gos- 

 samer often occurs upon the ground when there is 

 none in the air, yet the reverse of this has never been 

 observed ; for gossamer in the air, as in the instance re- 

 corded by Mr. White, is always preceded by gossamer 

 on the ground. Now, since the weather is constantly 

 calm and serene when these showers appear, it cannot 

 be the wind that carries the web from the ground into 

 the air. Again, it is stated that these showers take place 

 after several calm days^ : now. if the web was raised by 

 the wind into the air, it would begin to fall as soon a^ 

 the wind ceased. Whence I am inclined to think that 

 the cause assigned by Dr. Lister is the real source of 

 the whole phenomenon. Though ordinary observer^ 

 have overlooked them, he noticed these spiders in the 

 air in such prodigious numbers, that he deemed them 

 sufficient to produce tlie effect. 1 shall not, however,, 

 decide positively ; but, having stated the different opi- 

 nions, leave you to ycur own judgement. 



The next query is. What occasions the spiders to, 

 mount their chariots and seek the clouds ? Is it in pur- 

 suit of their food ? Insects, in the fine warm days in 

 which this phenomenon occurs, probably take higher 



" Rr. i's Lc'.Urs, SC. 



