d eee 
——————— eee 
. 
ON TEMPERATURE OBSERVATIONS IN LOCH EARN. 633 
fraying by constant use, and breaking. But considering the arduous nature of the 
work, especially during the nights, it says much for the enthusiasm of the observers 
that the interruptions were so few. 
CURRENT OBSERVATIONS. 
Two Ekman current-meters were available for the work, and, as already stated, these 
were in the charge of one of the observers. Observations with these were subsidiary to 
the main observations, and were not commenced until the temperature observations 
were in full swing, by which time the winds were light and variable and not favourable 
for producing currents. The observations which were made are given in Table I. 
appended to this paper, but it has not been possible to draw any clear conclusions 
from them. 
The current-meters used were not supposed to be accurate for currents of less than 
3 em. per second, but, except at the surface, it was rare to find currents of this velocity 
recorded. Observations were made at Station I. from 7th to 14th August. Apart from 
the surface observations, there were only four occasions on which currents of greater 
velocity than 2 cm. per second were observed, and three of these were on the same day, 
viz., 12th August. On the other occasion the velocity was only in excess of 2 cm. per 
second by a very small amount, and the directions recorded for currents at different 
depths were very various. 
Observations were made at Station III. from 15th to 20th August, and the currents 
observed there were much stronger. ‘The observations on the 18th were the most 
interesting, and on this day a strong west wind began to blow. At the surface there 
was a westerly current of 12 cm. per second, while at 7 fathoms (12°8 metres) there 
was an easterly current of 7°8 em. per second, and again at 10 fathoms (18°3 metres) a 
westerly current of about 4 cm. per second. ‘These observations afford a good example 
of a current below the discontinuity in the same direction as the surface current, and 
observations on other days show the same thing. 
At Station V. observations were made from 22nd to 27th August, but except on the 
25th, a day of strong west winds, little information was obtained. On that day the 
strongest currents observed (only 4°5 cm. per second) were at a depth of 9 fathoms 
(16°5 metres) and in an easterly direction. The currents at other depths were too 
feeble for any importance to be attached to them. 
As might have been expected, the current velocities recorded were much feebler 
at the ends of the loch than at the centre, for the current-meters only recorded 
horizontal velocities, and at the ends the currents have vertical components, and 
vortices are almost certain to be formed. The observations, however, suggest that 
the currents in lochs are not so simple as has been supposed, and there is considerable 
scope for their investigation. 
