60 On the Cultivation of French Pears in Scotland, tyc. 



fully exposed to the sun's rays. The border itself was twelve feet 

 wide, and the wall of about the same height in feet. On the 10th 

 of May, 1829, the author made four observations of these six ther- 

 mometers, between five o'clock of that day, and four o'clock of the 

 next, viz. at five a. m., one p. m., and at ten p. m. of the 10th. ; and 

 at four a. m. of the 11th. The results of these observations he has 

 given in a tabular form, of which a copy is exhibited. 



May, 1829. 



Cropped Border. 



Uncropped Border. 



















5 A. M 



55 



68 



58 



59 



75 



57 



62 



I P. M 



71 



69 



76 



86 



96 



113 



68 



104 



66 



10 P. M 



54 



69 



60 





81 





52 



60 



59 



55 



70 



58 



60 



Increase of temper- 

 ature from 5 A.M. 

 to 10 P. M 



Increase of temper- 

 perature from 10 

 P. M. to 4 A. M. 



16 

 19 



1 



18 

 17 



27 

 31 



26 



56 

 55 



42 



From this table it will be seen that at one o'clock p. m. the close 

 crop of cauliflowers occasioned a reduction of 18° of temperature on 

 the wall, as compared with that of the wall of the naked border : 

 at ten o'clock in the evening the difference of temperature between 

 the two portions of wall was 8° ; and even at four o'clock on the 

 next morning the difference was 5°. On the 29th of May the cropped 

 border was 4° lower than the naked one, at the depth of twelve 

 inches beneath the surface. 



This effect of cropping, in lowering the temperature of the atmo- 

 sphere, will however be much less when the sunshine is little and 

 partial through the day ; and when the day is wet it will not be 

 be observed. The colour too of the soil will influence the result, 

 a dark soil becoming much hotter than a light coloured one when 

 exposed in the same manner to the solar rays. 



