Affinity in the Combustion of Organic Compounds. 



69 



The mean of these including the paraffins is 36*7 ; but, since 

 this gives equal weight to each group, a fairer mean is 

 obtained from the figure which contains all Thomsen's 

 compounds. From this H 2 /wi m 2 = 38*6. Affinity between 



B*. 1200 

 XIO? 

 1100 



1000 



900 



800 



700 



600 



500 



400 



300 



200 



100 















































/ 























/ 























/ 



/ . 





















• 

 • > 























/ 





















• 

 • 



• / 



/ « 





















• ^r 



















9 



A 

 'A 



' 























o 





















V* 



**• 























fi 



• 











i 











25 $0 7§» tOO 125 J50 175 200 225 250 275 300b 



TR.TrL, 



Xl02. 



these typical compounds and oxygen is then very fairly 

 proportional to the product of the masses of the combining 

 molecules. 



5. The fact that the heat of combustion of organic com- 

 pounds is proportional to the number of oxygen atoms 

 required for complete combustion is now seen to be that an 

 affinity similar to the gravitational law holds over a wide range 

 of those compounds that are reduced to similar products of 

 both steam and carbon dioxide. Hydrogen and carbon 

 monoxide are not reduced to the same products, and their 

 affinities are not comparable in terms of heat of combustion. 

 For this reason it is impossible to compare the affinities of 

 elements thermally, and heats of oxidation of metals differ 

 widely. Prof. Bone's results are of special interest in the 

 case of hydrogen, since they show that the affinity of this 

 gas for oxygen follows the same mass law as organic com- 

 pounds, and that heat of combustion is only under strict 

 limits a reliable means of comparison. 



