RAINFALL AXD TEMPERATURE 189 



may be good, although a soil may be intrinsically 

 poor. Dr. Voelker replied that he was much 

 struck with the same fact when in India, adding, 

 *'It is very evident that these conditions must 

 have a most marked influence in enabling crops 

 to provide themselves with food. There can be 

 no doubt, I think, that under such conditions what 

 food supplies there are in the soil become more 

 quickly available than where we have such a 

 climate and physical conditions to deal with as are 

 met wath in England." This plantation, of some 

 fifty acres in extent, with soil "of a miserably poor 

 character," has recently been sold for <£3,000. 



It had a mean and annual rainfall of about 

 75 inches, and to this fact, and the extreme 

 humidity of the climate holding evaporation in 

 check, is to be traced the fertility of its soil. 

 The nearer we get to the Equator the greater 

 the power of the sun for evaporating moisture, 

 altitude being equal, and the greater the annual 

 rainfall required to peiTuit of a sufficiency of 

 water escaping from the pull of the sun to the 

 safe haven of the water-level beneath. In a 

 temperate climate a fall of 30 inches of rain 

 would be a sufficient if not a generous allow- 

 ance, but in an equatorial climate it would amount 

 to a drought. We have to think of the soil as 

 a great sponge soaking up w^ater from subter- 



