of the Fishery Board for Scotland. 



447 



Physical Observations made on Board H.M.S. 'Jackal' by Mr 

 Andrew King, off the Northern Coast of Scotland, and in 

 the Moray Firth. 



These observations were undertaken specially with the view of obtain- 

 ing data as to the physical conditions at Sandside Bay and Smith Bank, 

 Moray Firth, where flat-fish were at the time congregating in shoals for 

 the purpose of spawning. 



The observations made in January in the region immediately to the 

 north of the northern coast of Scotland are detailed in Table II. 



The neighbourhood of Sandside Bay was examined with special care, 

 but did not show any very marked peculiarity. 



The stations at which observations were taken are shown in the 

 accompanying chart, Plate XL and Sections 3 and 4 show at once the 

 depth and the vertical distribution of temperature observed at points 

 along two lines, the first running by intention approximately parallel 

 with and at about 15 miles distant from the coast ; and the other running 

 north and south at right angles to the first, starting from a central point. 

 It will be seen that the distribution of temperature along the east and 

 west section was very uniform. The maximum temperature observed 

 was 47°*3 F., at the bottom of Station XXV., and the minimum, 46° '1 F. 

 at five fathoms below the surface Station XXI. 



For the first 25 miles from west to east the extreme range observed 

 was from 47°*3 to 46° *7 F., and between the surface and a depth of 35 

 fathoms only from 47° 2 to 46°*8 F. ; so that for the great mass of the 

 water the range of temperature was ouly 0°*4 F. The highest tempera- 

 ture was found furthest west (Station XXV.) Between Station XXII. and 

 Station XXL, lying furthest east, that is nearest the North Sea, a distinct 

 fall in temperature, about 0°*6 F., was observed at all depths between 

 surface and bottom. The warm surface Atlantic water was being blown 

 at the time these observations were taken from west to east towards the 

 colder North Sea. 



The distribution of temperature along the north and south section was 

 even more uniform. At Station XIX., the surface temperature was 

 46° '3 F., but with this exception the temperatures observed never 

 exceeded 47° "3 F., and never fell below 46° *6 F. 



This uniformity in temperature was associated with a corresponding 

 uniformity in density. 



Along the 35 mile east and west section the density in situ varied only 

 between 1027*2 and 1027*5, and along the 35 mile north and south section 

 between 1027*4 and 1027*5. Close in to shore, in Sandside Bay, the 

 influence of the land water was rendered appreciable by a slight lowering 

 of the temperature, accompanied by a similarly slight lowering of the 

 density. 



As Dr Mill remarks, the temperature of sea water affected by land 

 water varies during winter directly as the density. In summer the 

 temperature varies inversely as the density. The slightly lower tem- 

 perature and the slightly lower density of this inshore water were, there- 

 fore, due to admixture with land water. 



Table III. gives in detail the observations made in the Moray Firth in 

 February 1889. These observations were unfortunately curtailed owing 

 to the very rough weather experienced. The taking of observations along 

 a line running north and south across the Firth had to be abandoned. 

 Section 5 shows the depth and the observed temperatures along a section 

 extending from the mouth of the Cromarty Firth, through the centre of 

 Smith's Bank, to a point about 55 miles out to sea. 



The lowest temperatures were observed between the Sutors at the 



