nd which, in
consequence, are navigated every day, as to those which are more remote,
but where, notwithstanding, the knowledge of these things may be of
great service to those who are destined to navigate them hereafter. To
this head also we may refer the great number of experiments which have
been made for enquiring into the depth of the sea, its temperature, and
saltness at different depths, and in a variety of places and climates.

"An extensive foundation has also been laid for improvements in
magnetism, for discovering the cause and nature of the polarity of the
needle, and a theory of its variations, by the number and variety of the
observations and experiments which have been made, both on the variation
and dip, in almost all parts of the world. Experiments also have been
made, in consequence of the late voyages, on the effects of gravity in
different and very distant places, which may serve to increase our stock
of natural knowledge. From the same source of information we have
learned, that the phenomenon, usually called the _aurora borealis_, is
not peculiar to high northern latitudes, but belongs equally to all cold
climates, whether they be north or south.

"But, perhaps, no part of knowledge has been so great a gainer by the
late voyages as that of botany. We are told,[55] that at least twelve
hundred new plants have been added to the known system; and that very
considerable additions have been made to every other branch of natural
history, by the great skill and industry of Sir Joseph Banks, and the
other gentlemen who have accompanied Captain Cook for that purpose."

[Footnote 55: See Dr Shepherd's Preface, as above.]

To our naval officers in general, or to their learned associates in the
expeditions, all the foregoing improvements of knowledge may be traced;
but there is one very singular improvement indeed, still behind, for
which, as we are solely indebted to Captain Cook, let us state it in his
own words: "Whatever may be the public judgment about other matters, it
is with real satisfaction, and without claiming any merit but that of
attention to my duty, that I can conclude this account with an
observation, which facts enable me to make, that our having discovered
the possibility of preserving health amongst a numerous ship's company
for such a length of time, in such varieties of climate, and amidst such
continued hardships and fatigues, will make this voyage remarkable in
the opinion of every b