The Exploding Bubble
If you take up a small quantity of melted glass with a tube, (the bowl
of a common tobacco-pipe will do,) and let a drop fall into a vessel
of water, it will chill and condense with a fine spiral tail, which
being broken, the whole substance will burst with a loud explosion,
without injury either to the party that holds it, or him that breaks
it; but if the thick end be struck, even with a hammer, it will not
break.