47 2 MISCELLANEOUS SUBJECTS 



then add every year more sun-power plants as the number 

 of inhabitants increases. 



An important advantage sun power has over coal power 

 is the fact that if a farmer or a community has a sun- 

 power plant they are absolutely independent. Strikes and 

 blockades cannot stop it, and it is not necessary to carry 

 a store of coal for contingencies. They are sure of their 

 fuel being always delivered free on board of their plant 

 and actually into their boilers. 



All the figures have been based on what we have 

 already done and the comparisons are made under present 

 conditions. We will, however, learn how to build better 

 and cheaper, because sun power is still very new. Every 

 year coal and oil will become more expensive, and there- 

 fore as time goes by conditions will become better and 

 better for sun power. 



Everyone knows how the price of oil has risen already, 

 and also that coal is rising, although much slower. We 

 are using to-day twice as much mechanical power as we 

 were using twenty years ago, and in twenty years from 

 now we will be using again twice as much, and prices of 

 coal and oil are bound to rise at a progressively greater 

 rate. 



The amount of power which can be secured from the 

 sun is, of course, unlimited. If an area of 143 miles 

 square at a favourable point in the tropics is planted with 

 mirrors spaced as wide apart as in our Cairo plant, this 

 area would furnish us with power and heat sufficient to 

 meet the demand in the entire world to-day. And this 

 area would be a mere dot on the desert of Sahara. The 

 sun throws down to the earth in three days as much heat 

 as would be produced by the combustion of our entire 

 earthly store of coal and oil. 



Sun power is most logical. We all know that the sun 

 is the central power-house of our universe, and we must 

 put ourselves in direct connection with this central power- 

 house. The sun is some 93,000,000 miles away, but never- 

 theless its rays reach us in five minutes, and we can catch 

 these rays and thrust them into our boilers, and this is 

 the direct and shortest possible method of securing 

 unlimited power. 



