630 Proceedings of the Royal Society of Edinburgh. [Sess. 
90 feet on 12th August and 12th September — but this deep direct current 
does not continue long. With a moderate breeze the return current makes 
its appearance with small velocity comparatively near the surface. With a 
strong wind it is met with very near the surface, and sometimes with a 
considerable velocity. 
The period from 30th July to 5th September contained no continuous spell 
of steady S.W. winds, so that deductions from the results are difficult. But 
from 12th to 19th September there was a fairly steady wind. Starting on 
the 12th there is a S.W. current down to 90 feet at least, and a balance in 
favour of a N.E. current at 210 feet. By the 14th the N.E. current is seen 
at 30 feet and strongly at 60 feet. On the 15th a N.E. current is registered 
at 25 feet. On the 17th there was a strong wind, and, as on 27th-28th 
August, there is a strong N.E. return current just below the surface. The 
loch was too stormy to use the current meter at the surface, but the velocity 
of the surface current was estimated from the drift of particles floating in 
the water at about 13 cm. sec. 
On the 17th the indications of direction are rather variable, but they 
indicate — 
At the surface a current from S.W. of 13 cm. sec. 
From 2 to 30 feet „ „ N.E. „ 4 to 5 ,, 
„ 30 „ 150 „ „ „ N.E. „ 3 „ 4 „ 
Below 150 feet the tendency of the current is from the S.W. This may 
be due to the existence of a secondary current in the same direction as the 
wind below the return current. There are also indications of this on 12th 
and 19th September, but the evidence is too slender to draw any sure 
inference. 
A point of difference between the observations from 12th to 19th 
September and the earlier observations is the greater strength of currents 
in deep water. Velocities of from 2 to 4'5 cm. sec. were not met with in 
deep water in August. This may either be due to the prevalence of a 
S.W. wind or to the fact that the temperature discontinuity was then at 
a greater depth. 
Fort Augustus Observations. 
The observations from 23rd September till 21st October 1908 were taken 
at a point near the head of Loch Ness, about 1 mile from Fort Augustus, and 
400 yards from the east shore, nearly opposite Glendoe pier (C on Sketch 
Map). 
As the canal authorities considered that mooring a large buoy in that 
position was a menace to shipping, we had recourse to other means, and a 
