368 
MR WATT OK THE HORI^TOJ^TAL 
Mr Blackwall of the Linnean Society, London, in a me- 
moir read before that Society last year, concludes that the 
gossamer spider has no power of elevating itself in this 
manner, except in the morning ; and that its ascent at 
that time is caused by the rarefaction of the air on the sur- 
face of the earth ; that the gossamers are then carried to 
great heights by the rarefied air as it ascends ; and that 
the gossamers descend in the evening as the upper atmo- 
sphere becomes cooled. 
I have no doubt Mr BlackwalPs observations are gene- 
rally correct as far as relates to the gossamer spider, and 
as far as regards the season of the year when they are seen 
flying most plentifully, which is in the end of October, and 
beginning of November. But at that season both the 
spiders and the most part of animated nature, have lost 
much of their liveliness and power. The gossamer spiders 
have then ceased to hunt for their usual food ; and it is 
highly probable that an incipient feeling of torpidity may 
impel them, as it does many of the feathered tribe, to seek 
by flight for that change of situation, which they actually 
obtain ; for the western breezes which then often occur must 
carry them to a great distance. The smallness of the ani- 
mal is no objection to this idea^ as several of the insect 
classes, particularly amongst the ant, bee, and spider genera, 
display in the circumscribed sphere allotted to them, as great 
a variety of instinctive faculties, as any amongst the fea- 
thered tribes. 
In the month of J une and beginning of August, I have 
often observed individuals of the gossamer species take 
their flight from the end of my finger, and ascend, at vari- 
ous times of the day, even in the afternoon, with a rapidity 
much greater than I should suppose to arise from the mo- 
tion of the rarefied air : and this has taken place either in 
the still air of an apartment, or in the open air when calm. 
