18 



Oxygen, carbon, hydrogen, and nitrogen form the whole 

 mass of the organic creation, living and dead, except the 

 small amount which would remain as ash, were such mat- 

 ter consumed at a red heat. 



Silicon, alumnium, magnesium, calcium, potassium, 

 sodium, sulphur, chlorine, and iron are the nine (9) princi- 

 pal inorganic elements, and with the two organic elements, 

 oxygen and carbon — hydrogen and nitrogen being found in 

 small quantities in mineral masses — make up more than 

 1000 <^f ^^^ solid crust of the earth. 



Mr. Dana happily calls these rock constituents "burnt 

 compounds" — as they are put into stable conditions by 

 uniting with a saturating quantity of oxygen — and ordi- 

 nary combustion consists in union with oxygen and the 

 formation of stable oxyds. 



The metals sodium and potassium burn if put in contact 

 with water and become oxyds. Calcium, by uniting with 

 oxygen, becomes lime; magnesium, magnesia; silicon, 

 silica; and aluminum, alumina. Thus saturated, or united 

 with all the oxygen they are capable of taking up, they 

 become inert matter, entering as ingredients into rocks, 

 and fit for dead nature, they are the most refractory sub- 

 stances in the earth's crust — and excepting pure crystalline 

 carbon, the least liable to change. 



The primary or granite rocks of the earth's crust are 

 aluminous silicates, being double compounds of oxygen 

 and silicon; and oxygen and aluminum; these chemical 

 compounds must have been formed from a fused state. 

 There are no means of knowing in what condition the 

 silicon, alumnium, magnesium, &c., of the now refractory 

 burnt compounds, existed before their combination; it 

 may reasonably be doubted w^hether they are not reall}^ 

 compound substances formed during the earlier condensa- 

 tion of matter, at all events they or their elements must at 

 some time have existed in a gaseous state, and as these 

 changes progressed there was a wonderful transformation 



