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98. Inclination or the angle at which the sun's rays 

 strike the earth, influences the temperature of the soil. 

 Where there is a sufficiency of moisture, more direct rays of 

 the sun causing greater heat of the soil, only result in richer 

 vegetation of the indigenous kinds. A, southern slope in the 

 N. Hemisphere is therefore 'desirable for moist climates ; but 

 a level soil helping retention of rain water on it is by far the 

 best for all ordinary purposes, in most parts of India. In 

 cold climates even radiation from walls '/is taken advantage 

 of in increasing the heat of the neighbouring soil and in 

 growing fruits on the walls to greater perfection. 



99. The Electrical influences of various classes of soils 

 on plant life in wet and in dry conditions, have not been 

 studied sufficiently minutely to enable us to give definite in- 

 formation on the subject. But this is the subject which is 

 being largely studied at present chiefly in France and Germany 

 and important results are anticipated from this study. Electri- 

 city has been applied to plants in two ways, (i) through the 

 soil by means of wires buried about 2 inches deep and (2) by 

 powerful arc-lights which act like strong sunlight, the light 

 being also softened by amber globes. Under this continuous 

 action crops have been matured in half the usual time, the light 

 being kept burning the entire night. As soon as the seed is 

 sown, the electric current is turned on by the underground 

 wires. Germination takes place quicker and more freely and 

 fully, and if the electric stimulation is kept up, growth goes 

 on more vigorously. An increased yield of 50 per cent, 

 over ordinary methods has been obtained by the application 

 of electricity in this way. It has been shown by experiments 

 conducted in Europe and in America that electricity can be 

 applied to ordinary agricultural purposes on a large scale. 

 Naturally electricity in the atmosphere is a potent agent in 

 converting -the free Nitrogen of the air into nitric acid which 

 as nitrates is afterwards utilised by plants. 



100. Sunlight. Solar rays of different colours are known 



