504 



KEPOET 1891. 



Monthly Means of Temperature Observations on the Aray at Inveraray. 



Thurso. 



Curves XXI. and XXII. give the weekly raeans of observations made 

 by Mr. David Gunn at Thurso, Caithness, near the month of the river, 

 and by Mr. John Gunn and Mr. J. B. Johnstone on the same river at 

 Dale about nine miles farther up stream. The detailed observations were 

 made the subject of a communication by Mr. John Gunn to the Scottish 

 Meteorological Society, and they are published in the Jotirnal of that 

 Society for 1888. At both stations the temperature of the water is under 

 that of the air for the whole year, even at a time when the river was 

 partially or completely frozen for several weeks. This apparent anomaly, 

 seen also in other curves, is probably due to taking the forenoon or 10 a.m. 

 observations of air-temperature as the basis of the curve, while the 

 minimum night temperature is really the chief factor in determining the 

 chilling and freezing of the water. 



