292 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1937 



mentary formations with their numerous unconformities witnessing 

 to repeated cycles of uplift and erosion, in the texture of the rocks, 

 and even in the mineral deposits witliin the rocks. 



Water in relation to life. — The work of water is no less evident in the 

 evolution of the plant and animal kingdoms. The Cambrian strata 

 contain the record of abundant marine life. In the half billion years 

 that have elapsed since the Cambrian period, both plant and animal 

 kingdoms have undergone vast evolution, with extensive and effective 

 adaptation for life on the land and even in the most arid regions. 

 However, in this long process of radical adaptation to different 

 environments, no species of plant or animal has escaped from the funda- 

 mental requirement of a water supply in order to carry on its life 

 processes. Deprived of water, all plants and animals would perish. 

 Deprived of water, the human race, with all its thought and emotion 

 and spiritual aspiration, would come to prompt oblivion. 



When consideration is given to the narrow range of temperature 

 and other conditions that are required to provide a utilizable supply 

 of water to living creatures, it seems evident that relatively few 

 heavenly bodies are adapted to support life as it is known to us. 

 Nevertheless, in the inconceivably large multitude of heavenly bodies 

 there may be, in the aggregate, many that have the proper conditions 

 for a water supply and that support living creatures comparable with 

 those that exist on this earth, or that existed In the Cambrian period, 

 or that will exist in ages yet to come. Moreover, it seems reasonable 

 to believe that there is a spiritual character to the universe which has 

 a reality and means of expression that are not limited by the special 

 physical conditions found on this earth. But, however incidental 

 water may be in the ultimate plan of the universe, for life on our own 

 earth its need is fundamental and inescapable. 



As the plant and animal kingdoms moved m large part from the 

 sea to the land, radical adaptations to their changed water supply 

 residted. Thus it became necessary for both the land plants and the 

 land animals to adapt themselves to the use of fresh water instead of 

 salt water, and this adaptation has become so thorough that now salt 

 water means death to nearly all land life. Thus also was developed 

 the constant-temperature adaptation of the warm-blooded animals, 

 operated by means of water acting as the medium for transporting 

 energy in the form of heat, and this has led to parental care and pro- 

 longed adolescence, and ultimately to the fruition of intellectual and 

 social evolution in the human race. 



Water in relation to human actidties. — With advancing civilization 

 the human race has found water to be a most convenient substance 

 for a large and ever enlarging list of uses. Indeed, its several proper- 

 ties, such as its solvent properties, its high specific heat, its occurrence 

 in the solid, Hquid, and gaseous states within convenient temperature 



