212 Miracles Ahead! 



quired 40 Ib. of salts. While large yields can also be obtained 

 with cereals, the cost of chemicals is here so large an item that 

 the method may not justify the cost of the equipment. 



Farming in the Desert 



Hogben believes "we can only guess at the wider implica- 

 tions of this biotechnical advance." Plant growth is limited by 

 three main factors: light energy, mineral salts, and water. 

 Agricultural production has hitherto been confined to regions 

 where the supply of these three essential elements is already 

 adequate, or, as with the last two, where the local supply can 

 be supplemented by manuring or irrigation without too much 

 trouble or loss. The energy of sunlight goes to waste over the 

 hot deserts where rainfall is scanty, and the sand will hold 

 neither water nor salts. Tank culture, on the other hand, limits 

 water loss to evaporation. 



The Great American Desert, and other wastelands in the 

 United States, may be turned into farms and factories by 

 hydroponics. And the city dweller may be able to balance his 

 food budget and give his family a better diet by rigging up a 

 soil-less garden in the living room. 



Growth-Promoting Techniques 



Exciting experiments have been conducted with growth- 

 promoting substances. Scientists in the Bureau of Plant Indus- 

 try of the Department of Agriculture have found that toma- 

 toes can be made to produce seedless, more solidly meaty 

 fruits by treating the plants with the fumes of naphthoxyacetic 

 acid. Previous methods of promoting plant growth usually in- 

 volved the use of sprays or even direct application of the sub- 

 stances to the plants. The new method saves a lot of time and 

 labor. 



