The form of a soda-water bottle is shown in fig. 2; it is made of
very thick glass, that it may resist the outward pressure of the
carbonic acid, and so formed that it cannot stand on its bottom, and
when laid on its side the bubble of air shall rise up to the middle
of the bottle and not to the cork, or else it would escape through
the cork before long, however nicely it may be fitted.