se
conditions, the time of high water eastward of Selsey Bill as far as
Dover is almost the same at all points, though somewhat earlier at the
east than at the west of this stretch of coast. The configuration of the
French coast causes a very strong tidal flow in the Gulf of St Malo,
with an extreme range at spring tides of 42 ft. at St Germain, compared
with a range of 12 ft. at Exmouth and 7 ft. at Portland. In the
neighbourhood of Beer Head and Portland and Weymouth Roads the streams
are found to form vortices with only a slight movement. On the eastern
(Selsey-Dover) section of the English coast the _maximum_ range of tide
is found at Hastings, with a decrease both eastward and westward of this
point.

Westerly winds are most prevalent in the Channel. The total number of
gales recorded in the period 1871-1885 was 190, of which 104 were
south-westerly. Gales are most frequent from October to January
(November during the above period had more than any other month, with an
average of 2.1), and most rare from May to July. It appears that gales
are generally more violent and prolonged when coincident with spring
tides than with neaps. The winds have naturally a powerful effect on the
tidal streams and currents, the latter being in these seas simply
movements of the water set up by gales, which may themselves be far
distant. Thus under the influence of westerly winds prevailing west of
the Iberian Peninsula a current may be set up from the Bay of Biscay
across the entrance of the Channel; this is called Rennell's current.
Fogs and thick weather are common in the Channel, and occur at all
seasons of the year. Observations during the period 1876-1890 at Dover,
Hurst Castle and the Scilly Isles showed that at the two first stations
fogs most frequently accompany anticyclonic conditions in winter, but at
the Scilly Isles they are much more common in summer than in winter, and
accompany winds of moderate strength more frequently than in the case of
the up-Channel stations. (O. J. R. H.)

_Salinity and Temperature._--The waters of the English Channel are
derived partly from the west and partly from the English and French
rivers, and all observations tend to show that there is a slow and
almost continuous current through it from west to east. The western
supply comes from two sources, one of which, the more important, is the
relatively salt and warm water of the Bay of Biscay, which enters from
the south-west and has a sal