104 



DR HUGH ROBERT MILL ON THE 



Beacon bearing N. one-sixth mile. The depth is 12 fathoms, in an isolated patch 

 shoaling inward to a shallow bar, and more gently seaward to a plateau of the minimum 

 depth of 8 fathoms, beyond which a tongue of deeper water leads westward to Dunoon 

 Basin, while it shoals eastward into the estuary. The average density of the water was : — 



Mean (7 observations) 



Maximum 



Minimum 



Surface. 



1-02223 

 102387 

 101985 



Bottom. 



1-02407 

 1-02477 

 1-023G7 



The average percentage of pure salt water at "Row" was 8 5 "7 at surface, 91 "3 at 

 bottom, or 90 "4 in vertical section, and it may be assumed for an ordinary year as 90 "1. 



Table XXXVIII. — Temperature Observations at Bow I. 



No. . . . 



1 



2 



3 



4 



5 



6 



7 



8 



9 



10 



11 



12 



13 



14 



Date . . 



13.4.86 



16.6.86 



4.8.86 



24.9.86 



11.11.86 



28.12.86 



25.3.87 



6.5.87 



13.6.87 



6.8.87 



29.11.87 



9.2.88 



28.3.88 



6.9.88 



No. of Pts. 



3 



3 



4 



4 



4 



6 



7 



2 



3 



8 



6 



6 



3 



6 



Temp. . . 



42 3 



48-7 



51-6 



53-1 



50-2 



44-0 



43-0 



46-1 



51-0 



55-8 



477 



44-5 



41-8 



537 



Slope . . 



+ 1-0 



+0-4 



+0-3 



+ 0-1 



-1-1 



-0-8 



-0-2 



+ 0-9 



+0-6 



+1-6 



-1-0 



-0-5 



-0-1 



+ 1-0 



The curves which were drawn from the observations were uniform in all cases except 

 No. 14, where the temperatures at surface, 5 fathoms, and bottom were 41°"9, 41°*6, and 

 42 0, 2, showing an intermediate minimum ; but as only three points were determined, this 

 may be neglected. Nos, 1, 2, 3, 4 showed a successive reduction of positive slope ; No. 4, 

 the maximum for the year, being practically homothermic ; Nos. 5 and 6 — the cooling 

 curves — were of greater range relatively, showing a marked negative slope ; but No. 7 

 was again almost homothermic, this time at the minimum. Nos. 8, 9, 10 had increasing- 

 positive slope as warming continued, No. 10 — the maximum — showing a range of 3° in 10 

 fathoms; Nos. 11 and 12 showed diminishing negative slope; and No. 13 is again a 

 homothermic minimum. 



The greatest range between surface and bottom temperatures was 4°*8, on 29th 

 November 1887, in 11 fathoms, the bottom being warmer; 3° of the change took place 

 in the first fathom. The effect was that naturally due to rapid surface-cooling. The 

 comparatively small vertical range in the curves, as a whole, is readily accounted for by 

 tidal mixture. 



The maximum temperature of the mass of water was 55°'8 in August 1887, and the 

 minimum 41 0, 8 in March 1888. Of the 15 soundings, 9 were made in the summer and 

 6 in the winter half-year, the water warming in the former, and cooling in the latter 

 season. The period of observation included three minima (in March or April) and three 

 maxima (in August or September). 



Observations at Row II — The observations were made just inside the Gareloch, Row 



