PLYMOUTH SOUND: ITS TIDAL CURRENTS. 283 
line of the Bridge early in the flood. The line of this disturbance 
is pushed outwards or inwards according to the relative strength 
of the opposing currents till, towards the end of the flood, it 
disappears and is replaced by a strong stream from the sea flowing 
towards Devil’s Point. The original stream still flows along the 
deep trough, and we can easily see how it impinges with great 
force on the rocks opposite the battery on Wilderness Point, causing 
the great boiling-up at this point all are familiar with. All the 
commotion, upheaval, and eddies at Devil’s Point thus arise from 
one cause; viz., the impact of the main trough-current on the rocks 
at the battery and its consequent reflections. 
The top-currents on the latter half of the flood are considerably 
different from the lower; for the main sets over the Vanguard 
Rock towards the Battery, evidently deflected by the strong stream 
flowing over the Bridge. Instead of an opposition of currents, as 
on the first of the flood, there is on the latter half a coalition ; both 
join quietly and flow onwards towards the Hamoaze. The velocity 
of these currents is very various, opposite Millbay ranging from 
one and a-half to three or four knots; so at Devil’s Point and along 
the Hamoaze quite as far as Keyham. On freshes the velocity of 
the ebb between Drake’s Island and Millbay is said to sometimes 
reach five knots per hour. 
The rebound of the main stream off Wilderness Point is taken 
advantage of by pilots in bringing ships into the Hamoaze; for the 
greatest care must be exercised to clear the strong eddy formed by 
part of this deflected current. Pilots make for Wilderness Point, 
where the water surges up, in the boldest manner; in a few yards 
the vessel will be brought up, and if on the proper swing will 
glide off towards Mount Wise. If this return is taken on the 
wrong bow, the vessel will swing round into the eddy in Barnpool. 
Part of the deflected main stream after impinging under the 
battery is shot off to Devil’s Point, where it again subdivides, part 
towards Stonehouse Pool, and part along the rocky shore to Bottle- 
nose Point, where it again comes in contact with the up stream 
and is returned, forming the well-known eddy between these two 
points. 
From the time the flood stream leaves Devil’s Point we have not 
the same interest in it on the present occasion, but the sets at half- 
tide, or when the currents are strongest, are tolerably well defined 
by the configuration of the bottom; for instance, the main flood 
