88 



DR HUGH ROBERT MILL ON THE 



warming of the 4 superficial fathoms, cooling by nearly f° of the next 19 fathoms, 

 and great warming of tire lowest 10 fathoms. The mean temperature of the section was 

 practically unchanged. The curves for both dates at Cuill were simply those of the 

 upper 15 fathoms, the compensating action of the lower layers not there coming into play. 



Curve 9 (fig. 36, Plate XXIX.), a simple parabola showing spring heating from the 

 surface temporarily arrested, is interesting when compared with the nearly homothermic 

 curve for Furnace (fig. 28, Plate XXVIII.) at the same date. The whole question thus 

 requires for its explanation a study of the vertical axial sections, many of the peculiarities 

 of temperature change being due to the upward surge of deep, cold water, caused by dis- 

 turbance of equilibrium by down-loch winds. This action is quite different at Dunderawe 

 and Furnace, the difference being due to the closed end of the loch lying beyond 

 Dunderawe, so that up-loch winds produce a banking-up and return-under-current of 

 surface water, while at Furnace the effect of a down-loch wind is to drive surface water 

 away to the Gortans Basin. 



Observations at Cuill. — This station, situated in mid-channel, near the head of 

 Loch Fyne, has the farm-house of Cuill bearing N. by W. 1|- cables. The depth is 15 

 fathoms. To the south-west the water deepens uniformly, to the north-east it shoals 

 steadily, the station being on the upper part of the ascending slope at the head of the 

 loch. 



The density of the water, as observed, is as follows : — 



Surface, 10 obsei'vations. Bottom, 9 observations. 



Mean, . . . 101435 ... 102427 



Maximum, . . . 102420 ... 102463 



Minimum, . . . 100114 ... 002359 



Average percentage of sea-water, 56"8 ... 93 - 4 



In vertical section 87 - 3, or for normal year 86'8. 







Table XXXII. — Temperature Observations at Cuill. 









No. ... 



1 



2 



3 



4 



5 



6 



7 



8 



9 



10 



11 



Date . . . 



20.4.86 



22.6.86 



11.8.86 



27.9.86 



17.11.86 



5.2.87 



29.3.87 



10.5.87 



16.6.87 



8.7.87 



15.8.87 



No. of Points 



7 



9 



12 



4 



9 



9 



5 



9 



9 



8 



7 



Temp. . . . 



417 



46-2 



51-1 



52-3 



48-7 



44-0 



44-4 



47-8 



49-5 



487 



53-1 



Sin],.' . . . 



o-o 



+ 5-1 



+ 7-4 



o-o 



-2-7 



-1-5 



-0-6 



+ 3-5 



+ 3-9 



+ 6-4 



+ 4-9 





12 



13 



14 



15 



16 



17 



18 



19 



20 



21 





Date . . . 



23.9.87 



5.11.87 



7.11-87 



17.12.87 



23.3.88 



2.6.88 



24.8.88 



25.8.88 



27.8.88 



17.10.88 





No. "f Points 



4 



6 



11 



12 



6 



3 



9 



6 



8 



6 





Ti mp. . . . 



53 1 



49-4 



49-6 



14-7 



43-2 



45-6 



52-8 



52-1 



53-7 



49-5 





Slope . . . 



+ 2*5 



-1-6 



+ 0-1 



-6-5 



-o-i 



+ 6-2 



+ 4-3 



+ 6-7 



+ 7-2 



+ 0-8 





