XXII.] ORGANIC AND INORGANIC EVOLUTIONS. 173 



tures, in centigrade degrees. Water freezes at a certain tempera- 

 ture above absolute zero, and boils at a certain other point ; these are 

 marked on our temperature scale. Then we have to remember that 

 about half way between the boiling point and the freezing "point, all 



30OOO* 



ARCONIAN 



AL.NSTAM5AM 



25OOO* 



ACHERNIAM 



ALCOLIAN 



2OOOO* 



MARKABIASO 



SIRIAN 



PROCYONIAN 



10000 



ARCTURIAN 



SOOO* 



PISCIAN 



OSM.ftlRID.MELT 

 IRON MELTS 



ORC.EVOL 



WATER OOILS 

 ICE MELTS I 



Fig. 44. Diagram showing that organic evolution occupies only a point in the 

 line representing the time and ternparature range required by inor- 

 ganic evolution. 



the organic life with which we are familiar on this planet, from the 

 geological evidence and our own experienca, must have gone on at a 

 temperature of somewhere about, let us say, from 50 to 40 C. There, 

 then, we get the limit of organic life in relation to the possible 



