432 COSMIC rniLOSOFHT. |M\ ii. 



union. But it is none the less true that an enormous supply 

 of heat implies such violent molecular undulation as to render 

 chemical union impossible. Since the mode of attractive 

 force known as chemism acts only at infinitesimal distances, 

 the increase of thermal undulation, which at first only causes 

 such a molecular rearrangement as to allow mutually- 

 attracting molecules to rush together, must at last cause such 

 a separation of particles that chemism will be unable to act. 

 This inference from known laws of heat is fully verified by 

 experiment, in the case of all those compounds which we can 

 decompose by such thermal means as we have at command. 

 Speaking generally, the most complex compounds are the 

 most unstable, and these are the soonest decomposed by heat. 

 The highly complex organic molecules of fibrine and albumen 

 are often separated by the ordinary heat of a summer's day, 

 as is witnessed in the spoiling of meat. Supersalts and double 

 salts are decomposed at lower temperatures than simple salts ; 

 and these again yield to a less amount of heat than is re- 

 quired to sunder the elements of deutoxides, peroxides, etc. 

 The protoxides, which are only one degree more complex than 

 simple elements, withstand a still higher temperature, and 

 several of them refuse to yield to the greatest heat which we 

 can produce artificially. No chemist, however, doubts that a 

 still greater heat would decompose even these. 



We may thus picture to ourselves the earth's surface as at 

 the outset composed only of uncombined elements, of free 

 oxygen, hydrogen, nitrogen, carbon, sulphur, etc., and of iron, 

 copper, sodium, and other metals in a state of vapour. With 

 the lowering of this primitive temperature by radiation, 

 chemical combinations of greater and greater heterogeneity 

 became gradually possible. First appeared the stable binary 

 compounds, such as water and the inorganic acids and bases. 

 After still further lowering of temperature, some of the 

 less stable compounds, such as salts and double salts, were 

 enabled to appear on the scene. At a later date came th« 



