TEMPERATURE OBSERVATIONS IN LOCH EARN. 



751 



9. Record at 10 metres for 24 hours commencing at 18 h. 5 m. on 18th August. 

 This record shows that a well-marked seiche is in progress, but the smaller 

 embroideries are not so much in evidence as might have been expected. The 

 variation of temperature in this record is about 5 '6° C, and is approximately from 

 15 '6° C. to 10° C. No observations with mercury thermometers are available either 

 on 18th or 19th August at the hour when the large changes are shown on the 

 thermograph. 



10. Record at 15 metres for 24 hours commencing at 15 h. 5 m. on 25th August. 

 The observations with mercury thermometers for the same period are shown in 

 fig. 10, and will be explained later. Attention may be drawn to the uniformity of 

 the curves above and below the discontinuity, and the small embroideries which 

 appear while the discontinuity is passing the instrument. 



Current Observations. 



In addition to the observations made with the new current-meter, a number of 

 observations were made with Ekman current-meters, of which two were available. 



With the exception of a solitary observation near the surface on 12th August, 

 22nd August was the only date on which currents of 2 cms. per sec. were recorded. 

 On 22nd August a steady westerly wind was blowing all day, force 6-7 on the 

 Beaufort scale, and, as the occasion seemed particularly favourable for the formation 

 of currents, a large number of observations were made. 



Surface 









II 





ytt 



l 





































5m. 



















9° 











10° 





















Wm. 





























9' 





















15m. 



















8-5° 

























































85° 





















Surface 



II h. 15 h. 



22nd August 1913. 

 Fig. 7. 



18 h. 



Fig. 7 illustrates the temperature conditions on this date. It represents the 

 depth at which the isotherms for 8*5°, 9°, 10°, and 11° C. occurred during the day. 

 The surface temperature varied from about 10° to 11° C, which was very low, 

 indicating that owing to the action of the westerly wind the warm surface waters 

 had been accumulated at the other end of the loch. On 20th August the surface 

 temperature at Lochearnhead was over 15° C. 



The following table gives all the observations made by means of the Ekman 

 meters on 22nd August. A number prefixed to a direction indicates that there were 

 two determinations of that direction, e.g. 2 S 80 W means that the current-meter twice 

 during the observation indicated a current of S. 80° W. 



