Trail functions. 7 



as applying to the temperature of the Solway rather than of the 

 estuary ; the width of the estuary at the point being more tlian 

 two miles, so that the water of the river must bear a very small 

 proportion to that of tlie sea with which it mingled. The obser- 

 vations in this case were taken daily for a whole year, from 1st 

 August, 1889, to 31st July, 1890. The means for the year of 

 air and water were precisely the same — 50-3 degrees. There 

 were seven months in which the mean temperature of the water 

 exceeded that of the air, viz., August, September, October, 

 November, December, February, and July. The observations of 

 the Nith estuary, taken at Kingholm Quay, showed that there 

 were two months out of the ten over which they extended in 

 which the mean temperature of the water was higher than that 

 of the air ; and if June had been included he had little doubt 

 there would have been three. In the case of tlie rivers the 

 temperature of the water did not rise above that of the air in 

 any month. Of the seven months in which this occurred in the 

 Little Ross observations, the most considerable excess was in 

 October, November, December, and February, when it ranged 

 from 2-2 degrees to 2-9 degrees. The conclusion he was led to 

 form was that the Solway Firth had a higher relative tempera- 

 ture than that of the rivers which flow into it— a fact which 

 might probably be explained partly by the influence of the Gulf 

 Stream, and partly by the much larger body of water represented 

 by the Solway, which secured greater uniformity of temperature 

 throughout the year. A table of seasonal variations for the 

 rivers and Solway brought out tlie following results :— Spring 

 Quarter (including March, April, and May)— Nith, 47-8 degrees; 

 Dee, 50-9 degrees; Solway, 47 degrees. Summer Quarter (June,' 

 July, and August)— Nith, 602 degrees; Dee, CM degrees; 

 Solway, 57-5 degrees. Autumn Quarter (September, October,' 

 and November)— Nith, 47-1 degrees; Dee, 49-8 degrees; Sol- 

 way, 53-1 degrees. Winter Quarter (December, January, and 

 February)— Nith, 38-9 degrees ; Dee, 40-2 degrees ; Solway, 43-5 

 degrees. It thus appeared that, while in spring and summer the 

 waters of the Solway had a lower temperature than that of the 

 rivers, the reverse held good in the autumn and winter. This 

 seemed to dispose of the idea that the higher relative tempera- 

 ture of the Solway was caused by the flowing of the tide over 

 the sands left bare at ebb and heated by the sun. In that case 



