CLYDE SEA AREA. 



73 



to the movements and thermal changes of its water, and the form and variations of the 

 temperature curves are of some interest. Speaking broadly, one would expect from the 

 configuration that Loch Fyne should differ physically from the Arran Basin in the same 

 way as the Arran Basin differs from the Channel, but to a greater degree. 



It is to be noted that I restrict the name "Loch Fyne" to what is sometimes called 

 Upper Loch Fyne. On ordinary maps and on the Admiralty chart the name is marked 

 as it is popularly applied to the whole surface of water stretching northward from Inch- 

 marnoch, thus including the Central Arran Basin. 



Observations at Otter II. — The station termed Otter II. has Otter Beacon bearing 

 S. by E. 2 cables, depth 20 fathoms. (Section 18 K, PI. 9 of Part I.) It is just inside 

 Otter Spit, where the tide runs very strongly, and on the sill of the Gortans Basin. The 

 average density of water at the station is as follows : — 



Surface, 4 observations. 



Mean, 1-02434 



Maximum, .... 102483 

 Minimum, .... 102383 

 Average percentage of pure sea-water, 930 



Bottom, 4 observations. 



102479 



102498 



102451 



95-7 



In vertical section 95'2, or in normal year 94 - 9 

 The water is thus considerably fresher than that of Skate Island in the Arran Basin. 



Table XXIV. — Temperature Observations at Otter II. 



No. . . . 

 Date . . . 

 No. of Points 

 Temp. . . 

 Slope . . 



10.8.86 



7 



50-3 



+ 2-8 



2 



17.11.86 



6 



500 



-11 



3 

 5.2.87 



3 

 44-3 

 -03 



4 



10.5.87 



6 



45-4 



+ 1-4 



5 

 15.8.87 



8 

 52-0 

 + 2-5 



6 

 23.9.87 



6 

 532 

 + 1-5 



7 



16.12.87 



6 



46-7 



-0-8 



8 

 3.1.88 



6 

 46-1 

 -0-3 



9 



14.2.8* 



6 



44-4 



-0-3 



10 



22.3.8! 



6 



42-9 



-0-9 



11 



16.10.88 



6 



49-9 



-0-3 



The temperature curves are usually straight or else very irregular, and this is also the 

 case to a less extent at Otter I. The appearance is largely due to the difficulty of keep- 

 ing station in the tideway, and the consequent uncertainty of taking two consecutive 

 soundings in exactly the same spot. 



The greatest positive slope shown was 2° '8, and the greatest negative slope — 1°*1. The 

 usual sequence of forms was shown, the homothermic, usually with a negative tendency, 

 preponderating at the minimum. The curves of heating were usually rather irregular 

 paraboloids, but No. 4 was a good example of an inverted curve. The best specimen of a 

 contorted curve was No. 6, which occurred at the maximum of 1887, and showed alternate 

 strata from the surface downward of warmer and colder water (fig. 26, Plate XXVIII.). 



In 1886, a number of surface temperature observations were made in passing Otter 



VOL. XXXVIII. PART I. (NO. 1). K 



