CLYDE SEA AEEA. 



75 



Observations off Gortans Point. — This station is fixed by Loch Gair entrance bearing 

 JS T .W. by N. 9 cables. The depth is 35 fathoms (Section 18, L, PL 9 in Part I.) in the 

 centre of the shallow and uniform Gortans Basin, which serves as a sort of trap between 

 the Upper Basin of Loch Fyne and the Arran Basin. 



The density of the water is as follows : — 



Surface, 9 observations. 

 Mean, .... 1-02398 

 Maximum, . . . 102452 



Minimum, . . . 102224 



Average percentage of pure sea-water, 92 - 7 



In vertical section 945, or in normal year 94*2. 



Bottom, 9 observations. 



1-02467 



1-02493 



102403 



94-9 



Table XXV. — Temperature Observations off Gortans Point. 



No. . . . 

 Date . . . 

 No. of Points 

 Temp. . . . 

 Slope . . . 



1 



2 



3 



4 



5 



6 



7 



8 



9 



10 



19.4.86 



21.6.86 



22.6.S6 



11.8.86 



28.9.86 



16.11.86 



29.12.86 



5.2.87 



29.3.87 



10.5.87 



7 



3 



11 



7 



7 



8 



6 



6 



12 



6 



42-2 



45-81 



44-9 



49-8 



51-6 



50-1 



46-4 



44-3 



44-1 



45-8 



+ 1-0 



+ 3-6 



+ 2-7 



+ 2-9 



+ 1-6 



-1-3 



-1-3 



-0-5 



+ 0-4 



+ 0-9 



11 



15.6.87 



9 



47-9 



+ 2-8 



No. . . . 



Date . . . 

 No. of Points 

 Temp. . . . 

 Slope . . . 



12 



13 



14 



15 



16 



17 



18 



19 



20 



21 



7.7.87 



15.8.87 



16.8.87 



23.9.87 



16.12.87 



3.1.88 



7.1.88 



14.2.88 



22.3.88 



4.6.88 



9 



12 



7 



6 



6 



6 



6 



6 



6 



6 



49-5 



51-2 



51-6 



53-1 



47-3 



46-0 



46-1 



44-9 



42-9 



45-7 



+ 4-2 



+ 3-7 



+ 3-4 



+ 1-7 



-0-8 



-0-4 



+ 0-3 



o-o 



o-o 



+ 1-6 



22 



16.10.8 



6 



49-9 



-0-1 



As a rule, the temperature at Gortans was more extreme than at Furnace on the slope 

 of the Upper Basin, being higher in the warming months, lower in the cooling. 



The small slope of the curves is remarkable, the greatest positive value being 4° - 2, 

 the greatest negative value, 1°"3. The range is almost entirely confined to the upper 

 10 fathoms, and often to the upper 5 fathoms, the lower 25 fathoms being usually 

 either homothermic or of very gentle and uniform slope. In fact, the general character 

 of the curve resembles that of the Arran Basin rather than that of barred lochs. 

 The size of the entrance and exit to the Gortans Basin relatively to its depth, taken 

 together with the strong tides which traverse it and the vertical mixing at the Otter 

 Bar, are quite sufficient to account for this effect. In discussing the temperature sections 

 it will be shown that the Gortans Basin plays quite a distinct part in the seasonal 

 temperature changes. 



Curve 3 is interesting, taken in connection with the fragment of Curve 2 (see fig. 27, 

 Plate XXVIII.), showing a mixing and cooling of the upper 5 fathoms, while the rest of 



