TRANSACTIONS. 



XVII. 



REPORT ON TEMPER.\TURE OF AIR AND WATER AS 



TAKEN AT THE RIVER STOUR, CANTERBURY, 



DURING THE YEAR 1890. 



BY THB LATE 



COL. W. H. HORSLEY, R.E. 



The following remarks on the above-mentioned subject are in 

 continuation of those given in the report for the year 1 889, and furnished 

 to the Committee of the British Association appointed to arrange an 

 investigation of the several variations of temperature in lakes, rivers, 

 &c., in various parts of the United Kingdom. The paper was also 

 published in Part I. of the South Eastern Naturalist. 



In the report for 1889, it was stated that in the months of 

 November and December the fluctuations of the relative temperatures of 

 air and water were frequent, but speaking generally, the water 

 temperature was higher than that of the air. The same remark applies 

 to the observations taken in January, 1890, though there ave some 

 remarkable exceptions, showing that the temperature of water is not 

 influenced so quickly as that of air. 



For instance, the temperature of the air, which had averaged 39° in 

 the first five days of January, suddenly rose on the 6th to 51°. 3 ; while 

 that of the water, which had been 44° on the 5th, only rose l°.6 on the 

 fith of the same month. The same was the case on the 12th of January, 

 viz. : air, 51°, water, 48°, with the wind S,W. & W., and again on the 

 16th and 19th, air, 50°. 3, water, 47°. 5, on the last mentioned date. 

 Another remarkable instance is reported on the 25th January, air 

 temperature, 54°, that of water, 44°. 5, difference, 9°. 5, that of air 

 having risen suddenly from 37° on the 24th, to 54° on the 25th, while 

 that of water had only risen 2°. 5 in the same interval. The weather 

 throughout January was unusually mild, the wind for the most part 

 S.W. with occasional rain. 



In February, the temperature of the water was, with one single 

 exception, higher than that of the air ; that exception proving the rule 

 mentioned above. The exception occurred on the 13th, the temperature 

 of the air suddenly rising from 81° to 45°, while that of the water 

 rose only 1°, viz. : from 39° to 40°. 



