128 



DR HUGH ROBERT MILL ON THE 



Temperature Sections of Loch God. — The deep basin of Loch Goil affords an 

 interesting contrast to the similarly formed but much shallower basin of the Gareloch, 

 the main difference appearing in its more sluggish temperature transactions, and, except 

 at the yearly minimum, its generally lower temperature. The seventeen sections (figs. 1 

 to 17, Plates XVII. and XVIII.) are drawn on the same scale as those of the Gareloch, 

 and are different in the ratio of horizontal to vertical scale from those of Loch Fyne. 



Table LI. — Temperature Observations at Lochgoilhead. 



No. ... 



] 



2 



3 



4 



5 



6 



7 



8 



9 



10 



11 



12 



13 14 



15 



16 



Date . . . 



17.6.86 



4.8.86 



24.9.86 



11.11.86 



12.11.86 



22.12.86 



25.3.87 



7.5.87 



14.6.87 



7.8.87 



29.9.87 



30.11.87 



10.2.88 



1.3.88 



28.3.88 



3.9-80 



No. of Pts. . 



12 



10 



7 



6 



1 



8 



6 



6 



7 



6 



4 



6 



6 



6 



3 



5 



Temp. . . 



44-5 



47-2 



48-4 



50"2 



49-6 



471 



44-1 



45-8 



50-1 



52-5 



54-0 



48-1 



45-7 



44-5 



43-1 



Slope . . 



+ 4-9 



+ 6-7 



+ 6-4 



+ 0-2 



+ 2-2 



-1-5 



-1-0 



+2-4 



+ 1-6 



+ 9-4 



+ 1-3 



-1-6 



-0-4 



+ 0-3 



-0-5 



+ 4'2 



Section I., 13th April 1886. — Observations at Dog Rock and Stuckbeg only. Flood- 

 tide. The temperature of the mass of water below 4 fathoms sank from 42° to 41°'5. 

 The top layer, traversed by parallel isotherms, was warmed to 44 0, 4 and 45°. No data 

 were afforded for determining circulation. There was no wind. 



Section II, 17 th June 1886. — Three sets of observations were made. The isotherm 

 of 46° ran horizontally at 4 fathoms. Below that there was a slight landward dip and 

 fall of temperature to under 42° ; above it probably a seaward dip, but want of an 

 observation at the mouth makes this uncertain. The surface water grew steadily cooler 

 as the loch was ascended. The tidal phase varied, and the wind was light from N.W. 

 No sufficient indications of circulation were shown. 



Section III, 5th August 1886. — Four stations. The isotherms were numerous, of 

 slight and various inclination, practically horizontal. That of 44° ran at 27 fathoms instead 

 of 12, as in June. Surface layers were warming rapidly, and the surface was growing 

 cooler landward. The tide was at the beginning of flood, and the wind light from the 

 south-east. The isotherms showed no disturbance on the bar. The deep water outside 

 was practically homothermic at 49° from the bar sill to the bottom, while inside it sank 

 to 43° "1 ; the bar thus shutting off cold water in the loch from water 5° warmer at the 

 same depth outside. 



Section IV., 2Uh Septemher 1886. — Three stations ; none at mouth. The isotherm 

 of 45° ran at 25 fathoms instead of 19 fathoms, as in August. The bottom temperature 

 inside was 44° - 2, while outside it was practically uniform to the bottom at 52°, a difference 

 of nearly 8°. Isotherms showed a very slight seaward dip, with tide at second half of 

 ebb, and there was no wind. The fall of temperature was most rapid just below the 

 level of the sill, there being a Sprung schicht at 17 fathoms. Above that the temperature 

 was practically continuous with that outside. 



