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Part III. — Ninth Annual Report 
treme than those for Ardrishaig, and the range, which is only 11°*0, is 
smaller than at Ardrishaig, and nearly equal to that at Oxcar. 
The daily range of temperature between forenoon and afternoon was 
0°'5 for the nine months of 1890, and 0°'3 for the three months of 1891. 
Classifying the results for different seasons, we find that for the warm 
months an average range of 0°'7, and for the cold months only 0°'3. 
Contrasting this average range for summer with that of Ardrishaig, where 
the conditions all point to a more marked difference being produced, we 
are led to consider why Ardrishaig should be so much less affected by 
summer sun-heating than Brodick. The reason seems to me to be that at 
Brodick the water along the shore comes, as a rule, from the surface of 
the wide East Arran Basin, except possibly in the case of a strong offshore 
wind. Near Ardrishaig, on the other hand, there is a strong up- welling 
of the deep layers at the narrow entrance to Loch Fyne, off the Otter 
Spit, on account of the tumultuous rush of the tides through that narrow 
channel, as I have proved in my paper on the ' Clyde Sea Area,' already 
referred to. This deep up-welling water tends not only to keep the 
salinity on the surface greater at Ardrishaig than at Brodick, but to 
equalise the temperatures at all times of the year, thus largely neutralising 
the effect of the great expanse of heated sand at the head of Loch Gilp in 
summer. 
At Brodick the changes in temperature, according to the season, went 
on much more uniformly than at Ardrishaig. This is well shown in the 
curves composing the two sets of observations. The maximum was 
reached in August, but the limits of the curve do not show the minima 
satisfactorily. 
The water off Brodick may be taken as, in all respects, the warmest at 
every season of the year in which observations have been made, and as 
presenting the most complete contrast in every way with the stations on 
the east coast. 
It is probable that in a few months the data available for a complete 
account of the temperature of the Clyde sea area will be greatly increased, 
as I am at present engaged in discussing the very numerous observations 
made during five years by the Scottish Marine Station. At present it 
would, therefore, be unprofitable to enter more deeply into this part of the 
subject. 
West Loch Tarhert and Loch Ryan. — At these lochs, the observations 
being recently commenced, cannot yet be looked on as altogether satis- 
factory. The mean temperature at Loch Ryan at 9 a.m. for the first three 
months of 1891 was 5°"0, much lower than either Brodick or Ardrishaig 
in the same months. Only at Oxcar and Abertay was the average tem- 
perature any lower. At West Loch Tarbert the observations are made at 
3 P.M., and the average was 5° '4 for the three months, being equal to that 
at the North Carr Rock, and much less than on the two stations on the 
Clyde sea area. Allowing for the difference of hour, the two lochs had 
practically the same mean temperature, which is a degree lower than the 
mean of Brodick and Ardrishaig. 
The important oyster fisheries of the two lochs gives special interest to 
the temperature observations. It will be necessary to continue the ob- 
servations for a year at least before any comparison of the conditions with 
those of other places can be made, and for a much longer time in order 
to determine whether any differences that may appear are permanent or 
temporary. 
