CHEMISTRY 215 



It may perhaps be urged that this argu- 

 ment is fallacious, in that the increase of the 

 relative amount of hydroxyl in the above 

 cases is larger than the relative change in 

 radicals of the types — CH 3 , =CH 2 , = CH, 

 and == C. But, in the first place, it is evi- 

 dent that the latter four radicals are actually 

 different, and a priori there is no reason to 

 suppose that they should not greatly differ 

 in their effect upon the properties of a mole- 

 cule, for instance, to render dissimilar the 

 compounds normal pentane CH 3 *CH 2 , CH2* 

 CH 2 • CH 3 and tetramethyl methane, 



CH 3 \ /CH 3 

 CH 3 /^\CH 3 , 



which is not the case. In the second place, 

 the change from methane, CH 4 , to ethane, 

 CH 3 CH 3 , is a larger proportional change in 

 the molecule than the change from alcohol, 

 CH 3 CH 2 OH, to glycol, CH 2 OHCH 2 OH, or 

 aldehyde, CH 3 CHO, both of which produce 

 far greater changes in the properties. 



In fact, the union of carbon with hydrogen 

 in organic compounds is a unique and peculiar 

 chemical relationship, upon which the proper- 

 ties of the carbon compounds, their number, 

 variety, and complexity largely depend. It 

 seems to make no important difference whether 



