top Of Spider s. : 
^Teats or Nipples near the Extremity of the’ 
Tail, whence a gummy Liquor proceeds* 
which adheres to any thing it is prefled 
again!!; and being drawn out, hardens in- 
flantly in the Air, and becomes a String or 
Thread, ftrong enough to bear five or fix 
Times the Weight of the Spider s Body. This 
Thread is compofed of feveral finer ones 
that are drawn out feparately, but unite to¬ 
gether two or three Hairs Breadth diftant 
from the Body of the Spider . The Threads 
are finer or coarfer, according to the Bignefs 
of the Spider that fpins them. Mr. Leeu¬ 
wenhoek computes, that an hundred of the 
fine!! Threads of a full-grown Spider are not 
equal to the Diameter of the Hair of his 
Beard ; and, confequently, if the Threads 
and the Hair be round, ten thoufand fuch 
Threads are not bigger than fuch an Hair. 
He calculated farther, that when young Spi¬ 
ders firfl begin to fipin, four hundred of them 
are not larger than one that is full-grown; 
and therefore the Thread of fuch a little 
Spider is fmaller by four hundred Times than 
the Thread of a full-grown one : allowing 
which, four Millions of a young Spider s 
Threads are not fo big as the fingle Hair of 
a Man's Beard 
m Phil. 'Trail/, Numb. 272. 
The 
