1 26 



DR HUGH ROBERT MILL ON THE 



effected, as in Loch Fyne, by a transition period of mixed slopes. When the Stuckbeg 

 curves (figs. 19 to 21, Plate VII.) are compared with the upper 44 fathoms of the Loch 

 Fyne curves (figs. 16 to 18), they are seen to be very similar indeed. Curves of the 

 same date are numbered and coloured alike, and the fact appears that the conditions 

 during the three years of observation varied similarly in both basins. 







Table L 



. — Typical Vertical T&m/peratv/re Curves at Stuckbeg. 





35 



1886-87. 





1887-88. 





1888. 



Reference 





Time 



Reference 





Time 



Reference 





Time 



> 

 U 



Table 



Date. 



Interval. 



Table 



Date. 



Interval. 



Table 



Date. 



Interval. 



O 

 I 



XLIX. 





Days. 



XLIX. 





Days. 



XLIX. 





Days. 



1 



April 13 





9 



Mar. 25 



45 



18 



Mar. 28 



48 



II 



2 



June 17 



65 



10 



May 7 



43 









III 



3-4 



Aug. 4-5 



48 



11 



June 14 



38 



19 



Aug. 15 



140 



IV 



5 



Sept. 24 



51 



13 



Sept. 29 



107 



20 



Sept. 3 



19 



V 



6 



Nov. 12 



49 



15 



Nov. 30 



62 



21 



Oct. 23 



50 



VI 



7 



Dec. 22 



40 















VII 



8 



Feb. 8 



48 



16 



Feb. 9 



71 









It is noteworthy that in these curves the point of rapid inflection is almost always at 

 20 fathoms of depth, both for positive and negative slopes, and below that depth there 

 is an approximation to homothermic change. The curves as a whole bear a considerable 

 resemblance to those of the Arran Basin. The homothermic character of the curves 

 poiuts to a more thorough mixture of the water of the loch than holds good for Loch 

 Fyne, but yet the seasonal phase was retarded at the bottom almost as much as in Loch 

 Fyne, the bottom minimum occurring in late spring, and the bottom maximum in early 

 spring, the rise of temperature from minimum to maximum occupying approximately nine 

 months, and its fall to the next minimum requiring only three. 



In 1886-87, which may be taken as an approach to a normal year, the range of tem- 

 perature at the surface was about 14°, at 10 fathoms 9°'5, at 20 fathoms (where the 

 abrupt change in the character of the curves begins) 6° "5, and below this depth to the 

 bottom the seasonal amplitude remained practically the same, thus differing sharply from 

 the condition in Loch Fyne. The retardation of the temperature phase at the bottom 

 makes the temperature region of Loch Goil still more unlike that of the Arran Basin. 



The Time-depth diagram (fig. 4, Plate III.) shows the condition of temperature-change 

 at all depths at Stuckbeg. It very closely resembles that for Loch Fyne, so far as the 

 depths correspond. The diagonal run of the isotherms is as well-marked here as in Loch 

 Fyne. In 1886 it showed that the surface was above 50° from July 12th to November 6th, 



