318 Proceedings of the Royal Society of Edinburgh. [Sess. 
difference between the observations there and at the end of the loch was 
the greater strength of the currents and their greater uniformity in direc- 
tion. The greatest velocity observed at the end of the loch (save at the 
surface) was 6 '7 centimetres per second at a depth of 45 feet on 19th 
August. Greater velocities than this were observed on five days at the 
centre of the loch, the greatest being a velocity of 13*2 centimetres per 
second at 50 feet on 19th August. On the whole, too, there was greater 
uniformity in the direction of the currents at the centre. Thus on 17 th 
August there was a current of 11*9 centimetres per second at 50 feet. 
West East 
15 cm.sec. 
60° 
Fourteen indications of direction were obtained, and they showed a varia- 
tion in direction of only 10 degrees. 
The most interesting observations are shown in figs. 2-7. In these 
diagrams the variation of the strength of the current with depth is shown 
by a continuous line. The portion of the curve to the right of the zero 
line represents easterly currents, and the portion to the left westerly 
currrents. Velocities are given in centimetres per second. The actual 
observations on which the curves are based are shown by crosses. The 
dotted lines represent the temperature distribution at the place of 
observations. 
Fig. 2. Observations on 17th August. There was a light westerly 
