of the Fishery Board for Scotland. 



423 



Roads at the head of the more open waters, and theestuary off Greenock 

 at the most distant point from the sea. Three only were on the east 

 coast, Kirkwall Bay in Orkney, which may be taken as representative of 

 the meeting of Atlantic and North Sea water, Wick Bay in the extreme 

 north-exst, and Cromarty Firth in the comparatively deep and sheltered 

 water of the Cromarty Firth, which may be viewed as the head of the 

 Moray Firth. 



The actual observations are published in the Tables, and, whenever they 

 were sufficiently numerous, as in the case of Rothesay, Stornoway, and 

 Invergordon, these results were combined in the form of means for 10- 

 day periods, and monthly means as well. The 10-day and monthly means 

 of the three Stations mentioned are published in this Report. Such ob- 

 servations made by expert observers from vessels afloat in water at least 

 deep enough to overcome the effects of purely local heating and cooling 

 are of very considerable value. Irregular as they are, they are worth more 

 than the regular readings taken from a pier or rock in places where the 

 water, in which the instrument was immersed, had flowed over rocks or 

 sand previously heated or chilled by direct exposure to the air. But on 

 account of the irregularity of the observations, being sometimes omitted 

 for several months at a time, and gaps of a week or a few days occurring 

 very often, the results are on the whole less satisfactory than those made 

 at lightships. 



In order to bring out the individual peculiarities of the three chief 

 cruiser Stations, Tables have been constructed, showing how the monthly 

 mean temperature varied with respect to some of the fixed Stations. 



Campbeltown Loch. — Observations were made in depths of from 9 to 

 12 fathoms, and as a rule the temperature was found to be practically 

 uniform from surface to bottom, the surface being a little warmer in 

 summer and a little colder in winter than the rest of the water. The 

 highest surface temperature observed during the sixty observations spread 

 over five years was 1 2°*7 on 21st June 188S, but the water as a whole was 

 warmest on 24th September 1890. The lowest temperature noted was 5°*7 

 on 16th February 1888. 



Lamlash Harbour. — This harbour is a deep bay on the eastern side of 

 Arran, the mouth of which is protected by Holy Island, leaving narrow 

 channels through which the tide runs strongly at the north and south. 

 The anchorage was at different times in depths of from 12 to 20 fathoms. 

 On no occasion was there any pronounced difference of temperature 

 between the surface and bottom ; differences of even half a degree were 

 rare, and in by far the greater number of cases there was not more than 

 one-tenth of a degree of variation. This is a somewhat remarkable state 

 of matters, closely resembling the condition of things which prevails out- 

 side the Clyde Sea Area in the open Channel, in which, by the way, 

 neither of the cruisers made any observations. It is obviously due to the 

 complete mixing of the water by means of tidal current-?, and the 

 temperature of the whole body of water, corresponding to that of the 

 surface in the 1 Firth of Clyde ' outside, shows that the bars across the 

 entrances to the harbour keep back the lower layers of the outside water, 

 and keep Lamlash harbour supplied entirely with the superficial waters. 

 The greatest warmth found was 13 0, 3 on 25th September 1890, the coldest 

 5°*6 on 7th March 1888. The water of Lamlash harbour is characterised 

 by remarkable transparency, and, being of comparatively high salinity, it 

 is a sort of natural aquarium swarming with invertebrate life. 



Rothesay Bay. — Tins bay formed the head-quarters of the cruisers on 

 the Clyde for the greater part of their stay in these waters. The geo- 

 graphical conditions of the bay are interesting, as it occurs where the 

 tortuous channel of the Kyles of Bute and the long straight trough of 



