308 On the Spiders’ Power of conveying their Threads {Aprit, 
was not easy to discover their operations correctly, from the ex~ 
treme exiguity of the threads. 
Having at length, however, procured one much larger than 
those I had formerly examined, I placed it on the post of trial, as 
usual, in such a situation that the sun shone full upon it, which 
enabled me to observe its movements precisely. The geometrician 
soon emitted, with surprising quickness, a pretty long line; and as 
1 wished to examine the end of it, to see if there was any thing 
peculiar in its conformation which caused it to stick so readily to 
any thing it touched, I broke the thread close by the straw, and 
drew it in by degrees. The only thing I could observe was, that 
it became more and more tenuous, till it turned almost invisible. 
This form of the line is perhaps necessary to its rising in the air. 
The spider then shot out another thread, which it strengthened by 
emitting a second alongside of the first, but not quite so long. 
After the two threads had united into one, it attached the line to 
the straw; and after drawing it in again with its fore legs till it 
became very short, and finding it did not catch hold of any thing,. 
not having been sufficiently long to reach the surrounding objects, 
it abandoned it, and remained at rest for some time, as if preparing 
for a greater effort to make its escape. It then dropped down by its 
thread an inch or two from the top of the straw, and ejected from: 
its spinners two threads at once, a good deal longer than the former 
ones, and added immediately a: number of lines in the same direc- 
tion extremely exile; but as the reflection of the sun’s rays was very 
bright from them, I could count about 14 distinct threads, which 
issued from the small apertures of which the spinners are composed. 
They soon all joined in one; and asthe spider seemed still to 
lengthen them, and guide them as if by magic, it evidently emitted 
from its spinners a stream of air, or it may be possible some subtle 
fluid of the electric kind, for the purpose of stretching out and 
coalescing the different filaments of which the thread was formed, 
as there was something which ran along the whole thread bringing 
it more into a horizontal position, making a kind of obtuse angle 
as it went along with the part that was flying upward. It then 
turned round as usual ; and fixing the line to the one it was hanging 
by, seemed to guide its movements for a few minutes, when the 
line fastened to the wall. It then drew it tight, and went across. 
I then put the spider upon the straw, and took it out to the garden. 
‘The wind was blowing very strong, and it rather seemed averse to 
move; but as I kept it in motion by touching it gently, it made 
another attempt to escape, as it found its situation not quite agree- 
able. From the time it continued letting out its thread, it must 
have been many yards long, asthe wind seemed greatly to facilitate 
the emission. The thread was, however, thrown to the ground and 
broken by an unsettled gust of the wind. 7 
They send out their threads with such celerity that they could 
eject, 1 should think, about 30 yards in a minute. It is. surprising. 
