14 l-'Ji >/' I L I .V . I (rim ( 'L 'I I'kK. 



The conditions <>/ tempcrdturc affecting agriculture+~-- 

 Mxtremes of heat and cold are equally active in bringing 

 the life of plants to a standstill. As the temperature 

 reaches an optimum for each plant, the plant is able to 

 absorb more food and is better able to utilise that food for 

 the purposes of life. The buds of trees only swell in 

 spring when the surroundings are at a certain temperature. 

 In the germination of seed, heat is of the greatest import- 

 ance, as unless it is raised to a certain temperature the 

 young embryo is unable to break into activity. In cold 

 weather seeds germinate slowly and in consequence are 

 in danger of decaying or of being destroyed by pests. 

 Excessive heat hinders or stops the growth of plants. 

 Late sown cereals are often killed or prematurely ripened 

 by the hot summer weather before the grain is fully deve- 

 loped. On the other hand, it is only in the south of 

 Egypt that the sugar-cane finds a sufficiency of heat to 

 enable it to bring forth seeds. Crops vary in their demands 

 for heat and it is therefore necessary to sow different 

 crops at different seasons. Increased temperature of the 

 soil increases the activity of all living bodies in the soil 

 and at the same time quickens the chemical changes in the 

 soil. In hay -making a high temperature is necessary as the 

 green crop, if not rapidly dried, quickly begins to ferment. 



Animals are able to withstand great differences in 

 atmospheric temperature but sudden changes have a very 

 detrimental effect on the animal system. The heat of 

 summer causes great perspiration and consequent loss of 

 heat to the animal body as well as exercising a bad effect 

 on the nervous system. When the temperature approaches 



