284 JOURNAL OF THE PLYMOUTH INSTITUTION. 
stream from the Devil’s Point sets for Mount Wise or Mutton Cove, 
and from this over and along the Rubble Bank, where an eddy is 
formed. Similarly on an ebb tide the stream is deflected from off 
the Rubble Bank towards Millbrook Lake; it speedily gathers up, 
turns, and sets along the Cremyll shore towards the Devil’s Point 
and the quay wall of the Victualling Yard. 
The ebb from the Hamoaze generally continues to run for half- 
an-hour into the flood, or after low-water; and a little before the 
last of the ebb on a calm day a tide-lining may be seen extending 
from off Millbay and Firestone Bay, where the ebb waters are 
finally overcome. After heavy rains the fresh water is carried on 
the surface of the salt, and where the top-currents meet, over the 
Bridge, and between Drake’s Island and Millbay a small wave is 
the result, as if the fresh water were rolling on the salt. On such 
occasions the stream will continue flowing outwards for two or two 
and a-half hours after low-water. On the 26th August, at 2:30 p.m. 
(low-water for that day 12:20 p.m.), this peculiar white ripple 
between the fresh and salt water was very strongly marked. 
The freshes on the Plym have repelled for some time in a similar 
manner the advancing flood ; sometimes the river water reaches as 
far round as Millbay before it is checked. The first of the ebb tide 
from the Hamoaze naturally sets across the Bridge, and continues 
to do so quietly till, as the level falls, and consequently the area of 
waterway over the Bridge is reduced to such an extent that the 
increasing ebb stream cannot be discharged, the whole is deflected 
and follows the course of the trough. 
The above is the course of events on the surface, but undoubtedly 
the deep trough is occupied by a mass of water moving along its 
course from the commencement of the ebb stream. This under- 
current, when suddenly deflected, as it is under the Bridge, drags 
the surface currents more or less into its own direction. Thus, on 
the currents being well established between the Bridge and Millbay, 
we have the surface currents suddenly changing and flowing at 
right angles to their former course without any apparent reason. 
This sharp turn in the surface current under Mount Edgcumbe and 
off the Bridge is continually taken advantage of by float-men, who 
land their rafts with surprising accuracy inside the Pontoon at 
Millbay, as from the point last mentioned under Mount Edgcumbe 
the stream sets directly into Millbay, striking the end of the Pon- 
toon and causing a sharp eddy in the outer half of the outer basin. 
