I. On Salt Solutions and Attached Water.
By FREDERICK GUTHRIE*.
§ 1. THE interesting paper read to the Physical Society of
London by Dr. J. Rae, the arctic explorer, on the
comparative saltness of freshly formed and older ice-floest, in-
duced me to examine some of the physical properties of brine
and some other of the aqueous solutions of the salts of the sea.
This examination has extended itself to some other salts; for
before attacking the problem of the freezing of sea-water, the
composition of which may be little less complex than that of the
earth itself, it seemed advisable to enrich our knowledge of the
properties of the solutions of some of its more abundant consti-
tuents in the separate form. Some of the experimental results
unexpectedly opened so wide and fascinating a field of inquiry,
that I have been compelled to make some sort of survey of it;
and though the results there gathered are of sufficient interest
to be considered by themselves as physical facts, they will assu-
redly also be concerned in the establishment of a sufficient
theory of thalattology.
§ 2. Being fortunately in possession of a large quantity of
extremely pure rock-salt in fine crystals, I satisfied myself by
the spectroscope of the absence of potassium and lithium. By
the usual tests, magnesium and sulphuric acid were also shown
to be absent. A determination of the chlorine agreed so closely
with the theoretical quantity that not more than 0.2 per cent.
* Read before the Physical Society, November 7, 1874. Communicated
by the Society.
† Proc. Phys. Soc. May 9, 1874. Phil. Mag. July 1874, p. 56.
Phil. Mag. S. 4. Vol. 49. No. 322. Jan. 1875.