TEMPERATURE OBSERVATIONS IN LOCH EARN. 



747 



The raft was moored at the head of the loch by means of four anchors (one at each 

 corner) in 30 metres of water, and another boat was moored at a distance of 650 metres 

 down the loch in 45 metres of water, for making simultaneous observations. The 

 positions of these two stations are shown on the map of the loch in fig. 5. Their 

 positions were obtained by means of cross bearings. 



Fig. 4. 



Thermograph Observations. 



As only one thermograph was available it was impossible by means of it alone to 

 follow the different temperature changes, and for this purpose observations with 

 mercury thermometers were relied on. The thermograph was used principally to 

 record in the neighbourhood of the discontinuity where it was anticipated rapid 

 variations of temperature would occur — for apart from the standing oscillations at 

 the surface of discontinuity there were certain to be at times slow-travelling waves 

 caused by local depressions in the upper layer. 



