CLYDE SEA AREA. 113 



Garelochliead had the saltest, Row I. the freshest surface water in the basin, a result 

 probably due to the flood-tide carrying in brackish estuary water. The weather was 

 dead calm. There had been strong south-westerly winds from the 1st to the 4th, 

 and after that date very disturbed weather. 



Section VII., December 28th, 1886. — Mean temperature of loch 44° *2, of superficial 

 five fathoms 43° *2. The cold surface layer was thinnest, but with greatest range of 

 temperature at Garelochliead. The isotherms of the surface 3 fathoms dipped gently 

 landward, below that level gently seaward. The tide was close to high -water. The 

 wind was blowing a gale from the north-west and west, in a general way down the 

 loch, but the tide appears to have more than neutralised its effect in disturbing the 

 layers of water except, curiously enough, at the mouth. 



The warmest water inside the bar was 45°'l on the bottom, that outside was 46°"0 on 

 the bottom, where the depth was only half as great as inside. 



Section VIII. , February 12th, 1887. — The mean temperature of the mass was 42°"8. 

 The isotherm of 42°"5 ran horizontally at 2 fathoms ; the others (43° and 43°*5 

 alone appeared) dipping very gently seaward. The tide was in the second quarter of 

 flood, and the weather was anticyclonic on the 1 2th, with a light south-easterly breeze. 

 A remarkably uniform distribution of temperature prevailed, showing the winter 

 cooling of the basin practically completed. 



Section IX., March 2btli, 1887. — The temperature of the mass of water was 43 o, 0, 

 almost the same as for Section VIII., but the upper 5 fathoms had become somewhat 

 wanner. The range of temperature being less than half a degree, it is impossible to 

 draw any conclusions regarding circulation from this section. A north-westerly gale 

 was blowing while the observations were taken, and the tide was in the first quarter of 

 ebb, hence there was a strong current setting out. 



Section X., May 6th, 1887. — The mean temperature of the section was 46°'0, and 

 that of the upper 5 fathoms, 46° '7, showing progressive heating, especially in the upper 

 layers, and toward the head of the loch. The line of 46° ran from the sill of 

 the bar (5 fathoms) to 2\ fathoms at the head. It so happened that a partial observation 

 was made off Clynder, which showed that the isotherms of the upper 2 fathoms clipped 

 thence landward to the head, while those from 2 to 5 fathoms dipped seaward ; but from 

 Clynder to Row II. the dip was landward throughout, thus showing a considerable 

 upwelling on the bar. The tidal phase was low- water at Shandon, and the beginning of 

 flood at Row. The wind was south-east, and light. The surface water warmed up very 

 rapidly from Row to the head. The appearance was that of an upwelling of colder water 

 at Row, combined with strong sun-heating, and perhaps slight accumulation of surface 

 water at the Garelochliead. 



Section XL, June 13th, 1887. — Rapid warming had gone on from the surface, the 

 mass-temperature being now 50°'7, and the upper 5 fathoms 51°-4. Stratification was 

 distinct, the isotherms below 5 fathoms dipping gently seaward, and above that level 

 showing an accumulation of warmer surface water about Shandon, and of cooler water 



VOL. XXXVIII. PART I. (NO. 1). P 



