144 



DR HUGH ROBERT MILL ON THE 



curves practically at the maxima. The air was warmer than the superficial 5 fathoms of 

 water for 1G4 days in 1886, 126 in 1887, and 134 in 1888, an average of 141 ; and the 

 air was colder than the superficial layer for 220 days in 1886-87, and 230 in 1887-88, 

 an average for the two seasons of 225 days. The average of the two complete cycles is 

 145 days of air warmer than water, and 225 of water warmer than air, or rather more 

 than 4£ months of the former to rather less than 7\ months of the latter. The propor- 

 tions being very similar to those for the other divisions. 



By interpolating probable values for the earlier months of 1886 and the later of 1888, 

 we are able to present in Table LVIII. the approximate annual mean temperatures of 

 water and air in Loch Strivan. 



Table LVIII. — Mean Annual Temperature of Air and Water for Loch Strivan. 



Year. 



I. Air. 

 Mean for Area. 



II. Air. 

 Mean for 

 Rothesay. 



III. Water. 

 0-5 fathoms. 



IV. Water. 



Mass. 



Difference. 

 Air II. and 

 Water III. 



Difference. 

 Air II. and 

 Water IV. 



18S6 . . 



1887 . . 



1888 . . 

 Mean . 



46-2 



47-0 

 46-7 



46-4 

 47-4 

 46-9 



47-0 

 48-6 

 48-2 



46-4 



48-1 

 47-3 



-o-6 



- I"2 



-i'3 



o-o 

 -0-7 

 -0-4 



46-63 



46-90 



47-91 



47-27 



- I'OI 



-°"37 



As regards the excess of the temperature of the mass of the water in Loch Strivan 

 over that of the air, the result is the same as for Loch Fyne and Loch Goil ; but the 

 excess of surface-temperature is less than in any other division. For the average of the 

 two years, 1886 and 1887, the surface water was warmer than the local air-temperature to 

 the following amount : — In the Channel, l° - 7 ; Arran Basin, 1°*7 ; Loch Fyne, 1° # 5 ; 

 Gareloch, 1°*8 ; Loch Goil, 1°*8 ; and Loch Strivan only 0°*9. This fact is evidently 

 connected with the ease with which the water of Loch Strivan is mixed by wind through- 

 out its whole depth ; thereby the mass of its water is brought more fully in contact with 

 the air than in any other division. 



The average temperature of the surface water for the three years under observation 

 was the same for the Gareloch, Loch Goil, and Loch Strivan, this being about half a 

 degree higher than for Loch Fyne. 



The Dunoon Basin. 



The Dunoon Basin is here considered as the channel extending from the end of the 

 north-eastern brancL of the Arran Basin, past Dunoon and up " Lower Loch Long," 



