PREFACE.
These two volumes consist cliiefly of an abstract of
the less technical portions of my own journal for the
first year of the voyage of the ‘ Challenger’ (1873),
and the early part of the fourth year (1870), when
slie again traversed the Atlantic on her way home.
Mith these 1 have incorporated some of tlie more
novel results of the observations of my eolleagues,
and I have added, usually in the form of Appendices,
such Meteorological Tables, Tables of depths and of
sea-temperatures, and Tables of specific-gravity determinations,
as shall be sufficient to place in the
hands of our fellow-workers in the field of Physical
Geography at all events an abstract of the data on
which our conclusions and speculations are founded,
and enable them to judge for themselves.
I had much hesitation in attempting to prepare
these volumes for publication, at sea ; ' for the last
four years the duties of each day have nearly fully
occupied our time : our minds have been continually
distracted by new impressions and by the necessity