gO THE BIOCOSMOS PRELIMINARY. 



exceedingly small, compared with Unlife or 

 the inorganic Earth. 



In the third place, the thermal limits of ter- 

 restrial Life are equally striking. Heat, the 

 diacosmical radiant, plays a most important 

 part not only in generating the planetary 

 system as a whole, but also in vitalizing our 

 globe. Yet the bounds are sharply drawn: 

 too -much Heat or too little destroys Life, 

 which, however, thrives on a certain amount 

 of it. Take the 180 degrees of the Fahren- 

 heit scale between the freezing and boiling 

 points ; the middle 100 degrees constitute the 

 range of temperature in which the vast ma- 

 jority of organic beings' exist. To be sure 

 there are exceptions both among plants and 

 animals which transcend the limits each way, 

 hot and cold ; still these exceptions do not get 

 very far from the border, but hover around 

 the general range of Life's temperature the 

 before-mentioned hundred degrees (or per- 

 chance a little more). Here the fact must be 

 brought out that this heat-scale of terrestrial 

 vitality is but a small part a dot as it were 

 of the total scale (or spectrum) of thermal 

 energy in the universe. The heat at the sur- 

 face of the sun has been variously estimated, 

 say from 8,000 to 20,000 degrees Centigrade, 

 and even more; but with any of these meas- 

 urements we see to what a little speck of a 



