468 MOTIONS OF INSECTS. 
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 to- 
gether, 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 becomé 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 otlier; 
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 showers take place after 
several calm days’; but, 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 observers have overlooked them, he no- 
ticed these spiders in the air in such prodigious numbers, that he deemed 
them sufficient to produce the effect. I shall not, however, decide posi- 
tively ; but, haying stated the different opinions, leave you to your own 
judgment. 
The next query is, What occasions the spiders to mount their chariots 
and seek the clouds? Is it in pursuit 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 atmosphere; and that the 
spiders catch them there, appears by the exuvie of gnats and flies, which 
are often found in the falling webs.* Yet one would suppose that insects: 
would fly high at all times in the summer in serene warm weather. Perhaps 
the flight of some particular species constituting a favourite food of our little 
charioteers — the gnats, for instance, which we haye seen sometimes rise in 
clouds into the air—may at these times take place; or the species of spiders 
that are most given to these excursions may not abound in their young state 
—when only they can fly—at other seasons of the year. 
Whether the same species that cover the earth with their webs produce 
those that fill the air, is to be our next inquiry. Did the appearance of the 
one always succeed that of the other, this might be reasonably concluded ; 
but the former, as I lately observed to you, often occurs without being 
followed by the latter. Yet, since it should seem that the aérial gossamer, 
though it does not always follow it, is always preceded by the terrestrial, 
this warrants a conjecture that they may be synonymous. Two German 
authors, Bechstein® and Strack4, haye described the spider that produces 
gossamer in Germany under the name of Aranea obfextrix, But it is not 
1 Ray’s Letters, 36. 2 Tbid. 42, Lister, De Araneis, 8. 
3 Lichtenberg und Voight Magazin, 1789, vi. 53. 
4 Neue Schriften der Natunfiract &e, 1810, v. Heft, 41—56, 
