ORIGIN OF LIFE ON THE SHORES OF THE OCEAN 115 



Oddie, B. C. V. 1959. Potassium/sodium ratio in rainwater. Nature, 



184, 1791. 

 Perutz, M. F., et al. 1960. Nature, 185, 416-422. 

 Rubey, W. W. 1955. Development of the hydrosphere, with special 



reference to probable composition of the early atmosphere. Geol. 



Soc. Am., Spec. Papers, No. 62, 631-650. 

 Wilson, A. T. 1959a. Organic nitrogen in New Zealand snows. Nature, 



183, 318. 

 . 1959b. Surface of the ocean as a source of air-borne nitrogen 



material and other plant nutrients. Nature, 184, 99-101. 



NOTES ADDED IN PROOF 



A recent study of the carbonaceous meteorites has, in my 

 opinion, completely altered the picture of the origin of carbon and 

 nitrogen compounds on the surface of the earth. Mason (1960) 

 has shown that these very rare types of meteorite, far from being 

 an aberrant product derived from proto planets, are in fact the 

 nearest we can get here on earth to the primary cosmic dust. The 

 key to this is the demonstrated presence in them of the 

 mineral chlorite, a hydrated silicate of formula (MgFe)3Si2072H20. 



Dr. Mason has shown convincingly, in my opinion, that from 

 these meteorites all the other types — chondrites, containing the 

 anhydrous silicate olivine (FeMg)2Si04 — can be derived by simply 

 heating to 600° corresponding to the abundant and stable chon- 

 dritic meteorites. On further heating, the carbonaceous material 

 reduces the iron-rich olivine to metallic iron in small particles in 

 the stony iron meteorites. If such meteorites agglomerate into 

 bodies of planetary size of 100-km diameter or if overgravitational 

 segregation occurs, the iron sinks to the center while the olivine is 

 melted and recrystallized and carries with it other light elements 

 such as calcium and aluminum, which crystallize as anorthite, 



CaAl2(Si04)2. 



It is from the breaking up of such bodies that Mason suggests 

 that the achondrite and iron meteorites are derived. This revolu- 

 tionary theory of meteorite formation is not yet generally accepted 

 but, whether true or not, there can be no doubt that carbonaceous 

 meteorites exist at the present time and may have been much more 

 abundant in the past. This means that we may have here an 



