28 DR HUGH ROBERT MILL ON THE 



previous year, distinctly above the average with regard to air-temperature. Only a 

 few observations were made, and these only in the southern part of the Area, 

 between the 18th and 20th, when light winds from east and south prevailed, on the 

 27th, during a heavy northerly gale, and the 30th, in a dead calm. The temperature 

 of the few stations examined on both occasions was found to be about a degree lower 

 than during Trip XV. Advantage was taken of the storm, on the 27th, to investigate 

 the action of wind in Loch Strivan. 



Trip XVII., February 1888. — Observations were made in the Gareloch on the 9th 

 and 10th in heavy squalls and a prevailing north-westerly wind. From the 11th to 

 15th the weather was fine, with a very light northerly wind, on the 15th the wind was 

 westerly, and on the 16th a light air from the south. On the 17th, the last day of the 

 trip, the wind rose to a gale from the north-east. The mean air-temperature of 

 February was fully 2°'5 lower over the Clyde Sea Area than the normal, thereby 

 contrasting with the exceptionally mild February of 1887, and approximating to the 

 great cold of February 1886. 



In the Channel the water had a temperature of 44° *8, but for the rest of the Area the 

 average was about 44° '3, with little change on account of depth in the more open basins. 

 At the head of the Arran and Dunoon Basins 45° '0 was found at the bottom, but the 

 warmest water occurred, as usual, in Loch Goil, which below 20 fathoms was within 

 0°'2 of 46°, and in Loch Fyne, where a well-marked intermediate maximum, over 46°, 

 occurred between the depths of 3 and 20 fathoms. 



The general condition was a reversion toward the simple arrangement of temperature, 

 homothermic as regards both depth and surface, which is characteristic of the spring 

 minimum. The curious fact, several times noticed before, that the whole mass of the 

 great Arran Basin was colder than the water of the Channel or that of the enclosed 

 lochs was again brought out, although the Channel was colder than usual proportionally. 

 In fact, at this period, or during the rise of temperature in summer, a rough map of 

 the configuration of the Sea Area might be sketched out by paying attention to 

 the temperature alone. 



Trip XVIII. , March 1888. — Observations were made on February 28th and March 

 1st, in calm weather, with a light north-easterly air ; and also on the 6th, 8th, and 10th of 

 March, with equally light south-westerly wind. The Dunoon Basin and Great Plateau 

 were alone studied in any detail, one observation each being also made at Skate Island 

 and Strachur. 



The water coming in from the Channel was rather under 43° in temperature, and in 

 crossing the Plateau it sank to 42°, being as cold as had ever been observed in that 

 position. The mass of the Arran and Dunoon Basins, so far as observations went, was 

 warmer, though showing a steady cooling throughout since the previous trip. The 

 Dunoon Basin showed greatest cooling at its seaward end, as if the Channel water were 

 chilling it — a mode of cooling strongly confirmed by the nearly uniform distribution of 

 temperature from surface to bottom and the absence of any marked surface-cooling. At 



