130 DR HUGH ROBERT MILL ON THE 



.1 slight seaward clip of the upper isotherms, and a slight landward dip of the lower, with 

 ebb-tide, and wind very light from west and south. Rapid heating of the surface layers 

 was in progress, the surface being above 49° ; a steady fall outside brought the 

 temperature to 47° at 15 fathoms, and 45°"2 at the bottom. A fall to 45° at 15 

 fathoms took place inside, and from that point the temperature was practically uniform 

 to the bottom. The fan-like spread of isotherms against the upper end of the loch 

 strongly suggests the effects of an on-shore wind on the west coast, while the arrangement 

 outside suggests the opposite action. 



Section XL, 7th August 1887. — Four sets of observations were made. This was 

 the section showing maximum temperature, and the isotherms were almost perfectly 

 horizontal, with tide at the beginning of ebb and the wind varying from a light 

 westerly breeze to calm. Outside, there was a gradually decreasing rate of fall of 

 temperature from 58°*2 on the surface to 49° on the bottom. Inside, there was a rapid 

 fall (equal with that outside to the edge of the bar) from 58°'6 to 47° at 23 fathoms, 

 and then a very gradual fall to 45° "4 at bottom. Thus the bottom temperature had 

 risen half a degree and the surface 6° since No. X. 



It is interesting to note that in August 1886 the distribution of temperature was 

 similar, and although the degree was lower, the difference of 4° between the bottom 

 temperatures on the two sides of the barrier was the same. 



Section XII., '29th September 1887. — On this occasion there were five stations, 

 observations being exceptionally complete. A general fall of temperature had taken 

 place in the upper layers since No. XL The temperature was unchanged at 15 fathoms, 

 and below that it had risen. Outside the bar the surface had cooled 4 c- 2, and the 

 bottom warmed 4°'l ; inside, the surface had cooled 4° - 3, and the bottom warmed only 

 2°'l. Outside, the water was now practically homothermic at 53°"5 ; inside, it sank 

 from 54°-3 to 47°-5. 



The isotherms showed a strong landward dip throughout the whole depth. 

 There was a very well marked banking-up of warm water at the head, and a distinct 

 uprising of cold water just inside the bar. The water was evidently being driven in, in 

 spite of the tide, which was in the first half of ebb ; a strong breeze was blowing from 

 E.N.E. As in the last and many previous cases, the isotherms about 18 fathoms lay 

 close and parallel, indicating the plane of junction between warm upper and cool lower 

 layers The easterly component of the wind would account for the homothermic water 

 of the Dunoon Basin being driven into Loch Goil, and thus give rise to the thick 

 warm layer deepening toward the head. 



Section XIII. , Wth November 1887. — Four stations were visited. The isotherms on 

 the whole were horizontal. The tide was in the last half of flood, and the wind both light 

 and variable. Continuous cooling of the upper layers had gone on, and outside the bar 

 the whole depth had cooled down equally. Inside the bar, cooling had taken place to 20 

 fathoms, where the temperature was the same as in the previous month, and below that 

 depl li I here was warming. At the bottom the water had reached the maximum temperature 



