1908-9.] Observations with a Current Meter in Loch Ness. 631 
series of empty petrol tins, etc., proved very successful, and was probably 
more efficient than the large buoy, which had a considerable area exposed to 
the wind, and swayed slightly in consequence. The depth of the loch at 
the point of observation was found by sounding to be 465 feet, or about 
twice the depth of the Invermoriston station. 
During the period of observation at Fort Augustus the prevailing wind 
was westerly, and as a matter of fact continuous easterly winds of any 
considerable strength would have made observation impossible. 
The currents observed seemed very complicated, and this may be attri- 
buted to a number of causes. With a westerly wind Fort Augustus is the 
windward end of the lake, and small variations in the direction of the wind 
are more felt than further down the lake, for the steep mountains which 
rise all along the lake tend to stereotype the direction of the wind. Cross 
currents may therefore be set up more easily at Fort Augustus than else- 
where. When an easterly wind is blowing, the depth of the lake is rapidly 
decreasing in the direction of the direct surface current, and this must 
have a disturbing effect on the currents setting in towards the shallowing 
shore. As evidence of the confusion which exists, two points may be 
mentioned : (l)the great variation in the direction of the currents registered 
during observations of only an hour’s duration, which means that in a large 
number of cases there was no steady direction for even an hour on end ; 
(2) compared with Invermoriston the velocities measured were small. 
The following are all the occasions on which velocities above 5 cm. sec. 
were observed : — 
Depth 
in Feet. 
Velocity. 
Cm. secs. 
Date. 
Direction. 
Wind. 
0 
8-0 
Sept. 24 
N.E. 
N.E. 1-2. 
0 
5-0 
55 
24 
N.E. 
N.E. 1-2. j 
0 
93 
55 
29 
S.W. 
S.W. 3-4. 
30 
9-0 
55 
29 
s.w. 
S.W. 3-4. 
120 
5-0 
55 
29 
N.E. 
S.W. 3-4. 
0 
5-1 
Oct. 
1 
S.W. 
S.W. 0-1. 
30 
5-1 
55 
1 
s.w. 
Variable. 
0 
54 
55 
3 
s.w. 
S.W. 1-4. 
90 
5-6 
55 
9 
s.w. 
S.W. 1-4. 
120 
6*7 
55 
10 
s.w. 
S.W. 3-4. 
0 
10-0 
55 
13 
N.E. 
S.W. 1-3. 
0 
9-8 
55 
16 
N.E. 
N.E. 3-4. 
30 
5-1 
55 
16 
N.E. 3-4. 
0 
51 
55 
19 
S.W. 
S.W. 0-1. 
0 
7-4 
55 
21 
S.E. 
Variable. 
Here there are fifteen cases, and in nine of these the observation is at the 
surface. The most curious fact of all is that the largest velocity recorded was 
