412 ON THE TEMPERATURE OF THE FRESH- WATER LOCHS OF SCOTLAND. 



Table I. 

 Monthly Means of Temperature at Fort Augustus. 





July. 



August. 



September. 



October. 



November. 



December. 



Date. 















1903. 



1904. 



1903. 



1904. 



1903. 



1904. 



1903. 



1904. 



1903. 



1904. 



1903. 



1904. 



Mean 

 Air Temp. 



54-9 



56-8 



54-0 



55-6 



52-6 



53-5 



46-4 



47-7 



42-1 



403 



357 



39-2 



Depth. 



























Feet. 































54-7 



51-4 



53-4 



56-3 



52-0 



535 



49-6 



49-3 



46-5 



46-8 



44-1 



43-7 



50 



51-0 



49-9 



50-7 



53-1 



51-4 



53-0 



49-2 



48-9 



46-5 



46-7 



44-0 



43-7 



100 



49-1 



48-1 



49-4 



50-1 



50-8 



51-5 



49-2 



48-4 



46-4 



46-6 



44-0 



43-6 



150 



47-6 



45-7 



47-4 



47-4 



49-2 



47-7 



48-3 



473 



46-2 



46-3 



44-0 



43-6 



200 



457 



44-5 



45-9 



45-3 



46-7 



45-0 



46-3 



45-6 



45-6 



45-6 



44-0 



436 





January. 



February. 



March. 



April. 



May. 



June. 



Date. 









































1904. 



1905. 



1904. 



1905. 



1904. 



1905. 



1904. 



1905. 



1904. 



1905. 

 49-5 



1904. 



1905. 

 56-0 



Mean 

 Air Temp. 



390 



40-5 



36-6 



38-1 



38-8 



41-0 



44-7 



42-2 



47-9 



54-1 



Depth. 



























Feet. 































42-7 



42-6 



41-9 



41-8 



41-5 



41-5 



41-5 



42-2 



436 





48-5 





50 



42-7 



42'6 



41-8 



41-8 



41-4 



41-4 



414 



42-0 



42-8 





46-4 





100 



42-6 



42-6 



41-7 



41-7 



413 



41-3 



41-3 



41-9 



42-6 





45-4 





150 



42-6 



42-6 



41-6 



41-7 



41-2 



41-3 



41-2 



41-8 



42-5 





44-0 





200 



42-5 



42-5 



41-5 



41-7 



41-1 



41-2 



41-1 



41-8 



42-3 





43-1 





The values for the mean temperature in July 1903 are probably too high, as do 

 observations are available for the first ten days of this month. Even without applying 

 any corrections, there is great similarity between the means for the two years. This 

 is especially noticeable from October to March ; but for the other months also the 

 similarity is very marked, and becomes obvious when the results are represented 

 graphically (fig. 1). From this I have felt justified in assuming that these mean 

 curves are typical of the curves for any one year in Loch Ness. I do not say that from 

 them any quantitative idea of the quantity of heat in the loch can be arrived at ; but I 

 do think that these curves are typical of the temperature distribution throughout the 

 loch. A month is a sufficiently long time over which to take an average, to eliminate 

 any local peculiarities from the type of the curve. I should hesitate in a wide loch 

 to draw any conclusions as to the temperature at the centre from observations made 

 near one shore, as I attribute the distribution of temperature very largely to the 

 influence of the wind, and the currents set up thereby, which are chiefly felt near 

 the shores. But in a narrow loch such as Ness every point is sufficiently near one 



