56 On the Cultivation of French Pears in Scotland, $*c. 



be not more than three or four feet deep, the temperature of its 

 water will not differ much, during the summer months, from that of 

 the soil of a border of similar depth. In such circumstances, water- 

 ing will rather augment than diminish the temperature of the soil ; 

 and will in no degree check the chemical changes by which the 

 food is prepared in the soil, or impede the functions of the living 

 organs destined to absorb it. Water from springs and wells, by 

 reason of its coldness, considerably reduces the temperature of the 

 soil, and ought not to be employed 'till its temperature has been 

 raised nearly to that of the soil. 



To ascertain the effects, respectively produced by spring and 

 pond water of different temperatures, Mr. D. in the year 1826, 

 made the following experiments : — he selected four peach trees of 

 the same species (Grosse Mignonne), which grew against a wall. 

 Two of these trees were supplied during the summer with water 

 taken from the spring, and the other two with water from the pond. 

 In the border where the trees grew, and which was twelve feet wide, 

 two thermometers were plunged into the soil to the depth of eigh- 

 teen inches, and its temperature carefully noted at the two stations 

 before the water was applied ; and also on the next day, or twenty- 

 four hours after the application of the water. The temperature too 

 of each kind of water was duly observed. These observations being 

 previously made, the border was watered three times during the 

 summer ; and each time as much water was given as would have 

 formed about a cubic foot of water over the whole surface. The 

 author has exhibited, in a tabular form, the times when the experi- 

 ments were made, the temperature of the soil, the kind of water, and 

 its temperature when used ; the temperature of the border twenty- 

 four hours after, and the amount of heat gained or lost by the kind 

 of water employed. 



The first experiment was made on the 10th of May. At the 

 depth of eighteen inches the temperature of the border was 64°, 



