CLYDE SEA AREA. 679 



rain. The densities observed were on the whole much higher than on the previous trip, 

 both at bottom and surface, but the same general distribution prevailed — freshest in the 

 lochs nearest the Clyde Estuary, the salinity increasing gradually seaward. The range 

 between surface and bottom salinity was as before — zero in the Channel, increasing to a 

 maximum at the heads of the lochs — Gareloch excepted. The salinity at the head of 

 Loch Goil was very much greater than that at the head of Loch Long on the surface, a fact 

 which is explained by the strong and steady north-westerly breeze sweeping straight down 

 Loch Goil while blowing transversely to Loch Long. Loch Strivan showed this effect 

 even better. On the 18th the wind blew strongly down the loch driving the fresher 

 water seaward, so that the salinity gradient was reversed completely at the surface, the 

 density at the head of the loch being 1 '02491, half way down 1'02448, and at the mouth 

 1-02384. The corresponding bottom densities were 1*02478, 1 '02490, and 1*02500. In 

 the Kyles of Bute the water from surface to bottom was much Salter than the average, a 

 fact especially noted in Loch Ridun, the fresh water of which seemed to be blown down 

 the East Kyle, while the salt bottom water of the Arran Basin was drawn in through the 

 west branch. When Loch Fyne was reached, on the 21st and 22nd, the wind was blow- 

 ing straight up the loch, and salinity decreased from mouth to head ; the salinity at Cuill 

 was, however, still high even on the surface At Otter the surface density was found to 

 be higher than any inside the Barrier Plateau, except the head of Loch Strivan, indicating 

 an up welling of Salter water, probably caused by the rush of the tidal current through the 

 narrow and shallow channel. The inward current had just ceased at the time of observa- 

 tion, which was at high water. At all stations but Cuill, this month was the maximum 

 for surface densities in Loch Fyne. 



Salinity Trip of August 1886. — From the middle of the June trip forty-nine days 

 elapsed to the middle of the August trip, which extended from the 3rd to the 12th ; no 

 observations, however, were made on the 8th and 9th. The rainfall of July had been 

 over the average in almost all parts of Scotland except that draining into the Clyde Sea 

 Area, where comparatively little rain fell, and in August the same unusual distribution 

 held good. The prevailing winds were south-westerly. During the trip a succession of 

 small cyclones passed over the area, producing constant changes of wind and frequent 

 showers. The commonest directions of the wind were south-west and south. During 

 this trip the area, as a whole, had the highest salinity observed in the whole period of 

 observation. The heads of Loch Goil, Loch Long, and Loch Strivan showed unusually 

 high salinity, but from Inveraray upward the surface water of Loch Fyne was unusually 

 fresh. The wind was blowing up all the lochs, but was a very light breeze, except in 

 Loch Fyne, where it was fresh on the 10th and stiff on the 11th. The trip is remarkable 

 in showing the maximum densities of surface water at nearly all stations except those in 

 Lpch Fyne and the Kyles, while it shows maximum densities of bottom water in Loch 

 Fyne and the Kyles, and at scarcely any other stations. This appears to indicate that 

 the increase of density in some cases affects the surface water first, in other cases the 

 deeper layers. 



