CLYDE SEA AREA/ 681 



greater on the surface than at Skate Island or Gortans ; this was at the end of flood-tide. 

 The stormy weather made it impossible to take samples in the East Arran Basin, but in 

 Kilbrennan Sound and on the Plateau to the south, the water throughout its whole depth 

 was fresher than between Skate Island and Garroch Head. It is noticeable that the 

 bottoms of the lochs were freshening much more slowly than all other regions, and were 

 now much Salter than the surface water of the seaward portion. The increase of rainfall 

 coincides with a marked general freshening. The Kyles were fresher on the west than 

 the east side. 



Salinity Trip of December 1886. — This trip, forty-one days later than the last, 

 occupied from the 22nd to the 30th of December. The weather of the latter part of 

 November was wet and stormy, while in December the storms continued, and the rainfall, 

 though very unequally distributed, was on the whole about equal to the average for the 

 season. During the trip the weather varied greatly. On the 22nd, when observations 

 were made on Lochs Long and Goil and the Dunoon Basin, there was continuous heavy 

 rain and a northerly breeze. On the 24th it blew stiffly from the north-west, changing 

 on the 25th to a gale from the south-west. The 26th and 27th were calm, with snow- 

 showers and frost ; on the 28th there was a westerly gale with squalls of snow and hail ; 

 but the 29th and 30th were calm and bright, with deep snow on the hills and ice on the 

 water. In spite of the rainy weather, the salinity of the Sea Area had increased gene- 

 rally since the November trip, and this was particularly observed at the head of the lochs, 

 the Gareloch alone showing freshening. Although the wind was blowing directly down 

 Loch Goil, the flooded streams and heavy rain prevented it from producing a greater 

 salinity at the head than at the mouth, although the gradient of density was so slight as 

 practically to prove the ascent of much salt water at the head. The most interesting 

 appearance was presented by Upper Loch Fyne. The night of December 29th had been 

 clear, dead calm, and intensely cold, and on the morning of the 30th, at 9.45, the air- 

 temperature was 32°, and the weather still calm and clear. In proceeding up the loch at 

 that hour the " Medusa" ran into a sheet of thin ice which stretched from shore to shore, 

 about 1 mile below Dunderawe and, as far as could be seen, extended to the head of the 

 loch. The ice was very smooth and glassy, forming a homogeneous sheet about f-inch 

 thick, and as it cut through the copper sheathing of the "Medusa's" bow, we had to 

 return without reaching the head of the loch. The temperature at a depth of 6 inches 

 was 41°, at 2 inches 35°*9. The ice was thus scarcely likely to be frozen loch-water. A 

 sample lifted by a bucket from under the ice had a density of 1*01815. Probably the 

 ice-cold water, oozing into the loch from the melting snow of the previous afternoon, had 

 spread over the surface as a thin sheet and froze solid while floating there. About 

 3 miles farther down the loch a similar sheet of ice had formed, preventing the " Medusa " 

 from leaving. On the following day the ice had vanished. Probably the belt between 

 these sheets did not freeze on account of the current of the swollen rivers Aray and 

 Shira. It seems to be only very small streams or simply surface drainage that can 

 spread their quota of snow-water so gently and smoothly over the surface" as to prevent 



VOL. XXXVI. PART III. (NO. 23). 5 K 



