4-i CHEMISTRY OF SOIL. 



If these com'bined in all proportions, then the possible num- 

 ber of combinations would be infinite. 



55. This can never be. Affinity is not equally powerful. 

 There is election or choice among the particles of inanimate 

 matter. When the Creator impressed this property upon 

 matter, He also limited its combinations. He assigned to 

 each element power to combine with other elements, only in 

 fixed, definite, invariable proportions. He gave to each its 

 form, weight, and measure. And thus were limited the 

 number of combinations, and the proportions fixed, in which 

 these combinations should ever, from the dawning, to the 

 end of time, occur. The Genius of modern chemistry has 

 taught that all bodies combine only by infinitely small par- 

 ticles. Holding her balance over invisible elements, she has 

 tauojht that each can be wei"jhed. 



It is the relative, not the absolute weight, which chemistry 

 determines. The mode may be thus illustrated : " Take 9 

 lbs. of water, pass its steam over a known weight of pure 

 iron turnings, heated red hot in an earthen tube. No steam 

 escapes from the tube, only air which may be inflamed and 

 burned. It is hydrogen gas, one of the constituents of water. 



That liquid has been decomposed. What has become of 

 its oxygen ? It has united with, and oxidated the iron. 

 What proportion of the 9 lbs. of water did it form ? 8-9ths. 

 If the iron is weighed, it will be found heavier in proportion 

 of 8 lbs. for every 9 lbs. of water evaporated and decom- 

 posed. Whatever is the proportion of water used, 8-9ths 

 are oxygen. Deducting from the 9 lbs. of water, 8 oxygen, 

 the balance 1 is hydrogen. These are respectively the 

 weights of their combining proportions. Chemical theory 

 supposes combination occurs, only by the ultimate, indivisi- 

 ble particles or atoms of matter. Hence, the combining 

 number is the relative weight of these atoms, referred to 



