318 On the Distribution of Temperature in 



fathoms, at which depth the temperature at Rowardennan 

 exceeds that at Rob Roy's Cave by 2-55. Although the 

 distribution varies at the different stations, there is little 

 difference in the mean temperature of the 30 fathoms, it is 

 higher at Rowcreeshie than farther north. From the surface 

 to ten fathoms the highest temperatures are at the lower end 

 of the basin, from 15 to 30 they are nearer the upper end. At 

 15 fathoms the temperature at Culness is lower than either 

 north or south of it. 



5/A September 1885. All day the weather was most favour- 

 able for experimenting, except perhaps at Culness, when it 

 threatened for a few minutes to blow and rain. Otherwise it 

 was almost quite calm, with overcast sky, so that there was 

 no overheating by the sun or cooling by the wind. 



Positions No. 5. Outer Ross Island bears S. 27 E. (true), 

 distant 0-74'. 



No. 6. Rowardennan Lodge bears N. 102 E. (true), 

 distant 0-43'. 



No. 7. Stuckgowan Lodge bears S. 67 W. (true), distant 

 0-32' to 0-37'. 



No. 8. Tarbet Pier bears S. 43 W. (true), distant 1-3'. 



No. 9. Inversnaid Inn bears N. 34 E. (true), distant 0-7'. 



No. 10. Stuckindroir House bears N. 60 W. (true), 

 distant 0-38'. 



All the places mentioned in this paper are to be found on 

 the Chart of the lake, page 339. 



Owing to the overcast state of the sky, there is little variation 

 in the temperature of the surface. Below the surface there is 

 again considerable variation, but the maximum range, 2-25 at 

 15 fathoms, is less than was observed on i8th August. The 

 character of the distribution is distinctly autumnal. On 

 1 8th August the observations were confined to the Tarbet 

 basin and were limited to 30 fathoms ; to-day they extend to 

 the three deep basins of the loch. The Ardlui and the Luss 

 basins resemble each other in that their maximum depth is 

 about the same 34 fathoms ; but the Ardlui basin is separated 

 from the Tarbet one by a ridge of probably 17 fathoms, while 

 the ridge shutting off the Luss basin has a maximum depth of 



