413 
of Edinburgh, Session 1885 - 86 . 
this date may be mentioned the rapid cooling which has taken place 
in the interval since 22nd September, the mean temperature of the 
first 30 fathoms having fallen about 3° F. at Ross Mill and Inver- 
snaid. It will be seen that in the Luss basin the distribution has 
become nearly quite uniform from surface to bottom, and at Ardlui 
the water is rapidly approaching the same condition. The tempera- 
ture of the water from the surface to 20 fathoms is practically 
uniform. At Ross Mill, in the Luss basin, and at Rowardennan 
and Stuckgowan, in the Tarbet basin, it is much alike, namely, 
49°*12, 49 o, 04, and 49°. At Inversnaid it has fallen to 48°'24, and 
Tig. 3. — Curves of Temperature, 15th October 1885. 
at Ardlui it is as low at 46° *5 8. The depth of water at Ross Mill 
and at Ardlui is nearly identical (34 fathoms), but the Luss basin 
is large, broad, and situated near the outflow of the lake ; while the 
Ardlui basin is small and confined, and situated close to the head of 
the loch, so that it might almost be taken as forming part of the 
embouchure of the river Falloch. On the 5th September the tem- 
perature of the water down to 15 fathoms was nearly alike in the 
two basins, but below 15 fathoms it was much colder at Ardlui than 
at Ross Mill, the difference being 1°*75 at 30 fathoms. 
In the following table the mean temperature of the water found 
between the surface and 20 fathoms, the surface and 30 fathoms, 
and between 20 and 30 fathoms, are given for Luss and Ardlui as 
observed on 5th September and 15th October: — 
