to reason
and experience. It is well known that where there are deep Inlets, large
Creeks, etc., into low lands, that it is not occasioned by fresh water
Rivers; there is a very great indraught of the Flood Tide, the direction
of which will be determin'd according to the possition or direction of
the Coast which forms the Entrance into such Inlets; and this direction
the Tide must follow, let it be ever so contrary to their general Course
out at Sea, and where the Tides are weak, as they are in general upon
this Coast, a large Inlet will, if I may so call it, attract the Flood
tide for many Leagues. Any one need only cast an Eye over the Chart to be
made sencible of what I have advanced. To the Northward of Whitsundays
Passage there are few or no large Inlets, and consequently the Flood sets
to the Northward or North-West, according to the direction of the Coast,
and Ebb the Contrary; but this is to be understood at a little distance
from land, or where there is no Creeks or Inlets, for where such are, be
they ever so small, they draw the flood from the Southward, Eastward, and
Northward, and, as I found by experience, while we lay in Endeavour
River.* (* Cook's reasoning on the course of the flood stream is quite
sound.) Another thing I have observed upon the Tides which ought to be
remarked, which is that there is only one high Tide in 24 Hours, and that
is the night Tide. On the Spring Tides the difference between the
perpendicular rise of the night and day Tides is not less than 3 feet,
which is a great deal where the Tides are so inconsiderable, as they are
here.* (* This difference in the heights of consecutive tides is termed
the diurnal inequality. It results from the tide wave being made up of a
large number of undulations, some caused by the moon, some by the sun;
some occurring twice a day, others only once. It occurs in all parts of
the world, but is inconspicuous on the coasts of Europe. In Australia it
is very marked, and occasions the night tides to be the highest at one
time of the year, when the Endeavour was on the coast, and the day tides
at the other. There are places on the east coast of Australia where the
range of the tide is very great, but Cook did not anchor at any of them.)
This inequality of the Tide I did not observe till we run ashore; perhaps
it is much more so to the Northward than to the Southward. After we had
got within the Reefs the second time we found the Tides more considerable
than