286 



REPORT ON THE METEOROLOGICAL OBSERVATIONS 



1874; at Gallowhill, outside the wood, the extremes occurred at 

 the same dates, and were 78°-l and 19°-8 — thus giving an annual 

 range of G0°-4 at Winterlaw, and 58°-3 at Gallowhill. 



At "Winterlaw the mean of all the maximum temperatures was 

 52°-2, and of the minimum temperatures 38°-8 ; these means at 

 Gallowhill being respectively 51°-7 and 38°-7. The means of the 

 night temperatures inside the wood are thus all but identical with 

 those at the station outside ; and an examination of the figures of 

 the table will show that they very closely approximated to each 

 other during the whole period. Indeed, if June be excepted, when 

 the difference was J -6, the difference did not exceed two tenths of 

 a degree. On the other hand, the means of the day, or maximum 

 temperatures, show an excess of 0°-5 in favour of Winterlaw. 

 A very remarkable difference is apparent when the months are 

 separately examined. This will appear from the following analysis, 

 in Avhich the plus sign indicates that the mean maxima at 

 Winterlaw exceeded, and the minus sign that they fell short of 

 the corresponding means at Gallowhill : — 



April, . 

 May, . 

 June, 



September, 



October, 



November, 



December, 



January, 



February, 



March, 



+ 1°-1 



. + l°-8 

 + l°-9 



July, . . . + 1°-1 

 August, + 0°-8 



1st to 15th September, + 0°-6 

 16th to 30th do. + 0°-2 



The remarkable fact here disclosed is this — During the annual 

 rise of temperature in the spring and summer months, the highest 

 temperature of the day inside the wood was from one to two degrees 

 higher than that outside the wood; and during the annual fall of 

 temperature in autumn, the highest temperature- of the day inside the 

 wood was on the mean about half a degree loicer than that outside 

 the wood. If the question was looked at solely with respect to the 

 conservative influence of trees on climate in modifying sudden 

 changes of temperature, a different result might have been expected ; 

 in other words, with the general annual rise in the temperature 

 of the air during the spring and summer months, the temperature 

 inside the wood might have been expected to have lagged behind, 

 and with the general fall of temperature in autumn, the tempera- 

 ture inside the wood might have been expected to have fallen less 

 quickly than outside. 



The explanation of the facts actually observed is probably this :— 



