The upper part of the cylinder, F, is filled with cotton wool
to prevent loss of mercury by spattering.
The material placed in A consists of a saturated solution of acid
carbonate of sodium, to which an excess of the solid salt has been
added. The sulphuric acid is the ordinary dilute. The apparatus, if
properly regulated, serves its purpose very well. The principal
precaution to be observed in using it is to avoid a too sudden
relieving of the pressure, which would, of course, result in the
introduction of an unnecessarily large quantity of sulphuric acid into
A.
* * * * *
WATER OF CRYSTALLIZATION.
By W.W.J. NICOL, M.A., D.Sc.
When a hydrated salt is dissolved, does it retain its water of
crystallization, or does this latter cease to be distinguishable from
the solvent water? Both views have found advocates among chemists who
have looked at the question of solution, and both have been supported
by arguments more or less to the point. But among the possible means
of solving this question there is one which has entirely escaped the
notice of those interested in the subject. And those who hold that
water of crystallization exists in solution have been entirely
oblivious of the fact that, while they are ready to accept the results
of the modern science of thermo-chemistry, and to employ them to
support their views on hydration, yet these very results, if correct,
prove without a shadow of a doubt that water of crystallization does
not exist in solution.
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