684 DR HUGH ROBERT MILL ON THE 



the season, and in June not half the usual amount of rain fell, some parts of the Clyde 

 drainage area in fact received only one-fifth of the usual rainfall. The memorable 

 " Jubilee anticyclone," which overspread the. British Islands for the first half of June, 

 brought great heat, dead calm or the lightest airs, and general haziness. The only rain 

 that fell during the trip was in the form of some drizzling showers on the 14th. In the 

 light of these conditions of climate the salinity results brought out are anomalous and 

 perplexing. The Gareloch was Salter than at any other time under observation, both at 

 surface and bottom, and the salinity increased uniformly from the mouth to the head of 

 the loch. The same arrangement of surface salinity was found in Loch Goil. The 

 Arran Basin, Plateau, and Channel were also at their maximum of salinity, and there 

 was a general slight increase in the density of bottom water in the landward portion. 

 But the surface of the landward portion was in very many cases fresher than in May, 

 and at Kilmun and Inveraray the lowest surface densities ever recorded were found. 

 With the exception of Gareloch and Loch Goil the surface water at the head of all the 

 lochs was remarkably fresh. Taken as a whole this trip showed great increase of salinity 

 in surface, and particularly in the bottom of the seaward portion, an increase in the bottom 

 water of the landward portion ; but a marked decrease in the surface, which had lost 

 almost all the extra salinity gained in May. The increase of salinity was evidently 

 taking place from the sea landward, and would appear to be due rather to the intro- 

 duction of salt sea-water than the evaporation of fresher surface layers. 



Salinity Trip of July 1887. — This was a short trip twenty-two days after that of June, 

 and occupied only from the 6th to the 8th. It was intended merely to run a rapid line 

 of observations through one set of characteristic stations, those chosen being from the 

 Plateau through Kilbrennan Sound to the head of Loch Fyne. June had been warm and 

 very dry, and in the early part of July the rainfall had also been low. During the trip 

 the 6th was dull and showery, but the remaining two days were bright, calm, and dry. 

 The highest surface density was found off Loch Eanza, the highest bottom density off 

 Skate Island. Loch Fyne had greatly increased its surface salinity, but the water off 

 Inveraray was again found fresher than that on either side. 



Salinity Trip of September 1887. — This was the last trip on which systematic 

 density determinations were made, and took place eighty days after that of July, occupy- 

 ing from the 20th to the 30th of September, but on account of various reasons no work 

 could be done on the 25th, 26th, and 27th. 



In July and August the rainfall was much under the average, especially in the south 

 of the Clyde drainage area, and during September it was close to the average for the 

 season. The first part of the trip, when the seaward portion — Loch Fyne and the Kyles — 

 was visited was calm, with mist or haze, on account of a well-marked anticyclone. The 

 latter part was dominated by an equally well-marked cyclone, north-west and south-west 

 winds prevailing on the 26th and 27th, the central calm happening on the 28th, and a 

 stiff north-east breeze, with frequent squalls, being encountered on the 29th and 30th. 



The conditions were very similar to those of the previous trip, except that the. surface 



