Importance of Water 23 



1916) Professor Chamberlin tells us how the young 

 earth, more or less cooled down, became enwrapped in 

 an atmosphere laden with "planetesimal" dust which 

 sank gently on to the surface and drifted about in 

 billowy, changeful dunes. By its early "ultra-Kraka- 

 toan" atmosphere, containing little free oxygen, but 

 abundant carbon dioxide, water-vapor, and nitro- 

 gen, "the young earth was blanketed against inten- 

 sities of radiance from without (a younger, more 

 intensely radiant sun) and from inequalities of ra- 

 diance from within." This curtaining and blanketing 

 atmosphere was the first positive preparation for the 

 emergence of living organisms, and we recognize its 

 importance more clearly when we remember that the 

 average living creature is adapted to mild tempera- 

 tures and gentle reactions. Life is a tender plant, ill 

 suited for violent vicissitudes. 



Time passed, and from the growing atmosphere 

 water began to condense on the cooling earth. It was 

 absorbed by the dusty mantle, till by and by in the 

 hollows among the dunes there appeared the gleam 

 of pools and lakelets, from which grew lakes and sea. 

 Perhaps the waters covered the earth with a universal 

 sea. In any case, to the atmosphere there was added a 

 second "preparation" for life, a hydrosphere. 



In his Order of Nature (Harvard, 1917) Pro- 

 fessor Henderson has worked out the panegyric of 

 water. It can dissolve a larger variety of substances 

 in greater concentration than any other liquid; it is 

 a very mobile vehicle ; it can split things up in hydro- 

 lytic cleavage. An enormous quantity of heat is 



