462 HYBERNATION OF INSECTS. 
their sensations affected by the cold some days before it 
comes on, in the same way as we know that spiders and 
some other animals are influenced by changes of wea- 
ther previously to their actual occurrence. But once 
more I refer to my meteorological journal ; and I find 
that the average lowest height of the thermometer, in 
the week comprising the latter end of October and be- 
ginning of November 1816, was 434°; while in the week 
comprising the same days of the month of the end of Au- 
gust and beginning of September it was only 449°—a dif- 
ference surely too inconsiderable to build a theory upon. 
I have entered into this tedious detail, because it is of 
importance to the spirit of true philosophizing to show 
what little agreement there often is between facts and 
many of the hypotheses, which authors of the present 
day are, from their determination to explain every thing, 
led to promulgate. But in truth there was no absolute 
need for imposing this fatigue upon your attention; for 
the single notorious consideration that in this climate, 
as well as in more southern ones, we not unfrequently 
have sharp night-frosts in summer, and colder weather 
at that season than in the latter end of autumn and be- 
ginning of winter, and yet that insects do hybernate at 
the latter period, but do not at the former, is an ample 
refutation of the notion that mere cold is the cause of the 
phenomenon. If, indeed, the hybernacula of insects 
were simply the underside of any dead leaf, clod, or stone, 
that chanced to be in the neighbourhood of their abode, 
it might still be contended, that such situations were 
always resorted to by them on the occurrence of a certain 
degree of cold, but that they remained in them only 
