t 
. 
232 Miscellaneous Intelligence. 
IIL MisceLnanerous Screntiric INTELLIGENCE. 
1. On the sudden cooling of melted Glass and particularly on 
“ Rupert's Drops ;” by V. DE Luynes.—The bursting produced in 
It is supposed that the external layer, suddenly solidified by cool- 
i i i much expanded, co 
The experiments whose results I have the honour to present to 
the Academy seem to prove, on the contrary, that the effects in 
The mechanical actions by means of which the drops are ordina- 
rily broken necessarily produce vibrations in the glass, the effect 
of which it is impossible to appreciate. That is why, in this inves- 
tigation, I have preferred to make use of fluohydric acid, the action 
of which can be moderated at pleasure, and which permits us to 
a at will, and without any shock, any portion we wish to 
tac 
divergence of the pair), equilibrium is always broken; the drop 
then separates into a great number of fragments, and in most 10 
t drops 
the experiment is arrested at different stages of the dissolution, It 
is found that the nucleus which remains presents no longer the 
properties of the original drop; it no longer breaks up when the 
thin end is broken off—which shows clearly that the interior mass 
of the glass does not intervene in the phenomenon, 
