lighter than air. But why thefe apterous infefls fhould •that day
take fuch a wonderful aerial excurfino, and why their webs fhould
at once become lb grols and material as to be conliderably more
weighty than air, and to defcend with precipitation, is a matter
beyond my fkill. If I might be allowed to "hazard a fuppofition,
I fhould imagine that thofe filmy threads, when firft (hot, might be
entangled in the riling dew, and fo drawn up, fpiders and all, by a
brilk evaporation into the regions where clouds are formed : and
if the fpiders have a power o f coiling and thickening their
webs in the air, as Dr. Lifter fays they have, [fee his Letters to
Mr. Ray] then, when they were become heavier than the air,
they mull fell.
Every day in fine weather, in autumn chiefly, do I fee thofe
fpiders Ihooting out their webs and mounting aloft: they will 'go
eff from your finger if you will take them into your hand. Laft
fummer one alighted on -my book as I was reading in the parlour ;
and, running to the top of the page, and Ihooting out a web, took
it s departure from thence. But what I moft wondered at was,
that it went off with confiderable velocity in a place where no air
was ftirring; and I am litre that I did not aflift it with my breath.
So that thefe little crawlers feem to have, while mounting, fbme
loco-motive power without the ufe of wings, and to move in the
air fafter than the air itfelf.
L E T T E R XXIV.
S e l SO R N E , A u g . I£t lyygt
TO THE SAME.
d e a r s i r ,
T h e r e is a wonderful fpirit of focidlity in the brute creation
independent of fexual attachment: the congregating of g r e J
nous birds in the winter is a remarkable inftance.
Many horfes though quiet with company, will not flay one
tmnute ,n a field by themfelves: the ftrcngeft fences cannot
reftram them My neighbour’s horfe wifi not only not flay by
himfelf abroad, but he will not bear to be left, alone in a ftrange
ftable without difcovering the utmoft impatience, and endeavour
“ g to kreak the rack and manger with his fore feet. He has
been known to leap out at a liable-window, through which dung
was thrown, after company.; and yet in other refpedts is remarkably
quiet. Oxen and cows will not fatten by themfelves; but-
will negleft the fineft pallure that is not recommended by fociety 1 - - -
It would be needlefs to inftance in Iheep, which contend/*----- V
flock together. *
But this propenlity feems not to be confined to animals of the
fame fpecies; for we know a doe, ftill alive, that was brought
up from a little fawn with a dairy o f cows; with them it goes
a-field, and with them it returns to the yard. The dogs of the
houfe take no notice of this deer, being ufed to her • but i f
ftrange dogs come by, a chafe enfues; while the mafter fmiles
to fee his favourite fecuyely leading her purfuers over hedge, or
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