[ 1 8 ° ] 
it was lodged. But when I touch’d this little Cylin- 
der, it was reduced to Powder, much in the fame 
manner as is faid to have happen’d to fome Men 
who had been ftruck with Lightning. Now, it was 
not polliblc for this Glafs to receive, or convey to 
the Body of the Drop any Vibrations ; or if any, 
they mud be infinitely fmall ; and yet the Effeft was 
precifely the fame as ufual. Therefore the Syftcm of 
Vibrations is not happier than thofe invented before 
it. 
It is among the Glafs- workers, and in their Art, 
that the Secret of the Lacryma Batavica, or Glafs- 
Drop, is to be fought j and there it is that I think i 
have difeover’d it. 
All thofe who have feen Glafs-houfes know, that 
when a Piece fails in the Hands of a Workman, he 
throws it aftde; and this Piece is not long expofed 
to the Air, before it breaks in Pieces : And when 
the fame Workman has fucceeded in making a Piece, 
and is willing to preferve it, he takes great Care not 
to let it cool in the Air; but carries it hot into an- 
other Oven of a moderate Heat, where he leaves it 
for a certain Space of Time. And this laft Opera- 
tion is called Annealing the Glafs. 
A natural Philofopher, who is Witnefs to this 
Management, ought to inquire into the Reafons and 
Neceflity of it. 
How comes it that the Glafs, which cools in the 
Air, breaks ; and when it has been nealed, it docs 
not break ? This is the Reafon, if I am not mif- 
taken. 
A Bit of melted Glafs, red-hot and liquid at the 
fame time, is in that Stare, purely bccaufe its Par- 
ticles are divided by fo great a Quantity of Particles 
of 
