How very curious! The wire is almost white hot, and a pungent smell rises from the glass. Pray how is this accounted for?
MRS. B.
This is owing to a very peculiar property of the vapour of ether, and indeed of many other combustible gaseous bodies. At a certain temperature lower than that of ignition, these vapours undergo a slow and imperfect combustion, which does not give rise, in any sensible degree, to the phenomena of light and flame, and yet extricates a quantity of caloric sufficient to react upon the wire and make it red-hot, and the wire in its turn keeps up the effect as long as the emission of vapour continues.
CAROLINE.
But why should not an iron or silver wire produce the same effect?
MRS. B.
Because either iron or silver, being much better conductors of heat than platina, the heat is carried off too fast by those metals to allow the accumulation of caloric necessary to produce the effect in question.
Ether is so light that it evaporates at the common temperature of the atmosphere; it is therefore necessary to keep it confined by a well ground glass stopper. No degree of cold known has ever frozen it.
CAROLINE.
Is it not often taken medicinally?