62 THE FUTURE OF ARID LANDS 
faster than physiologically desirable. He refers to heat acclimati- 
zation, by which is meant the physiological changes resulting in 
an improvement in work following exposure in a hot environment, 
and he believes that man can live under conditions more severe 
than occur in the hottest parts of the world. Protection from direct 
solar radiation is desirable in the form of a light broad-brimmed 
hat or a canopy on a tractor over the driving seat. 
Good housing is essential—cool by day and of a kind to give 
adequate protection at night. In this respect the thick-walled, 
small-windowed, pisé houses of the Near East, Pakistan, and 
India are types. 
Water is the essence of life, and it seems a pity that because of 
religious beliefs or tradition desert dwellers do not take to the 
use of galvanized iron tanks to store roof water. 
Desert dwellers may suffer from prickly heat and from mal- 
nutrition and vitamin A deficiency which leads to slow healing 
of wounds. 
We who live in comfort find it hard to realize what life is like 
without electricity or gas, without water in pipes, without re- 
frigeration and radios, air conditioning in buildings, good roads 
and fast cars, and so forth. But many thousands live where 
hydroelectric power is not available nor where fossil fuels like 
coal and oil can be used. So we turn to such sources of power as 
wind and sun. 
Successful wind-driven generators up to 70 kilowatts capacity 
are operating in Denmark, and two prototypes of 10co kilowatts 
are functioning in the United Kingdom. Much thought is being 
given to automatic regulation in variable winds in order to make 
the fullest use of wind power. It is most important to choose the 
right site for a windmill. 
The use of wind power to pump water either directly or through 
the use of electricity should result in saving bullock power and 
thereby acreage for human food. 
Solar energy has already been put to work for cooking and 
heating water and we saw demonstrations of equipment in action 
at New Delhi, India, in November, 1954. The problem is to 
reduce the cost to within the means of the average Indian. In 
