MOTIONS OF INSECTS. 343 
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 the air, as in the 
instance recorded 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 show- 
ers 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 as 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 ob- 
servers have overlooked them, he noticed these spiders 
in the air in such prodigious numbers, that he deemed 
them sufficient to produce the effect. I shall not, how- 
ever, decide positively ; but, having stated the different 
opinions, leave you to your 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 
flights than usual, and seek the upper regions of the at- 
mosphere; and that the spiders catch them there, ap- 
pears by the exuvize of gnats and flies, which are often 
found in the falling webs®. Yet one would suppose that 
2 Ray’s Letters, 36. b Tbid. 42. Lister De Araneis, 8, 
