86 



DR HUGH ROBERT MILL ON THE 



isolation on thermal conditions, and shows how much the ready change of temperature 

 in natural bodies of water depends on free circulation. 



Observations at Dunderaive. — At the observing station, Dunderawe Castle bore 

 N. 21 cables, soundings being made in the centre of the loch at a depth of 35 fathoms. 

 This was on the slope towards the head of the loch, about midway between the head and 

 the relatively flat floor of the deepest part, the slope being much more gradual than 

 that near Furnace at the other end. The observed density of the water was as 

 follows : — 



Surface, 9 observations. 

 Mean, ..... 1-01914 



Maximum, .... 1*02440 



Minimum, .... 1-00657 



Average percentage of sea-water, . . 70 - l 



In vertical section 90 - 2, or in normal year 89"8. 



Bottom, 9 observations. 



1-02450 



1-02479 



1-02412 



94-2 



Table XXXI. — Temperature Observations at Dunderaive. 



No. . . . 

 Date . . . 

 No. of Points 

 Temp. 

 Slope . . . 



1 



20.4.86 l 22.6.86 



9 

 41-8 

 + 0-3 



9 

 44-5 

 + 5-1 



3 



11.8.86 

 10 



47-9 



4 

 27.9.86 



7 

 50-0 



+ 9-7 +7-3 



5 



17.11.86 



12 



49-0 



-1-9 



6* 

 30.12.86 



15 

 47-0 

 -4-0 



7 

 5.2.87 



6 

 44-5 

 -2-6 



29.3.87 



13 



45-0 



-0-9 



9 

 10.5.87 



9 

 .45-8 

 + 5-2 



10 



16.6.87 



14 



47-3 



+ 6-1 



11 



8.7.87 

 12 

 47-9 



+ 8-2 



13 14 



23.9.875.11.87 



8 

 5M 

 + 4-8 



10 

 49-8 

 -1-1 



15 



7.11.87 



12 



49-6 



+ 0-6 



16 



17.12.87 



15 



47-0 



-4-7 



17 



14.2.8! 



12 



45-9 



-2-1 



18 



23.3.8* 



6 



43-2 



-0-4 



19 

 2.6.88 



9 

 45-3 



+ 2-4 



20 



24-8-88 



13 



49-2 



+ 9-7 



21 



25.8.88 



10 



49-3 



+ 10-1 



22 



17.10.8 



6 



49-0 



+ 2-3 



* West of Dunderawe. 



Curves of very slight slope, showing almost homothermic conditions, occurred three 

 times — Nos, 1, 15, and 18. No. 15 will be specially alluded to, the others were both 

 early spring curves at or near the minimum temperature of the year. 



Curves of great range are represented by ten positive and five negative cases, most 

 of which arc somewhat irregular. Cases of well marked intermediate minimum in 

 the positive curves occurred in No. 2 (June 1886), and of intermediate maximum in 

 a negative curve in No. 5 (November 1886) and No. 17 (February 1888), the latter 

 being a very well formed sickle shape. 



The main feature of the Dunderawe curves, like those for Inveraray and Strachur, is 

 their great diversity of detail, showing compounds of the clearly recognisable types. 



The steepest gradients were 2 0, 8 and 2°*6 in successive single fathoms from to 2 



