32 PLANT LIFE ON THE FARM. 



favours transpiration of the fluid. A high degree of 

 temperature, as might be expected, favours transpiration, 

 as does also a dry state of the atmosphere. The condition 

 of the plant, its age, and other circumstances are also im- 

 portant agents in regulating the amount of transpiration. 



Some idea of the amount of water given off may be 

 gleaned from some experiments made by Sir John Lawes, 

 and recorded in the Journal of the Horticultural Society 

 for 1850, thus During 172 days, March 19 to September 

 7, the total weight of water given off from small flower plots 

 containing plants grown without manure, was as follows : 



Grains. 



Wheat 113,527 



Barley 120,025 



Beans 112,231 



Peas 109,082 



or, say, an average loss for each pot for the whole period 

 of over 100,000 grains. To show the effect of the season, 

 it may be said that the average daily loss in grains in the 

 case of flower pots containing plants of wheat grown in 

 unmanured soil was : 



Grains. 



March 19 to 28 . 14.3 



March 28 to April 28 40.9 



April 28 to May 25 162.4 



May 25 to June 28 1177.4 



June 28 to July 28 1535.3 



July 28 to August 11 . . . ... 1101.4 



August 11 to September 7 ..... 230.9 



Barley lost more in April and May than the wheat, and 

 more also in July and August. Beans lost much less than 

 either of the cereals, the amount increasing regularly to 

 June to July and diminishing in August. Peas evaporated 

 less than beans, especially in June. The results obtained 



