Mr. M. M. P. Muir on Isomerism. 



163 



the formula CH (CH 3 ) (0, H 5 ) OH ; and to tertiary butylic 

 alcohol the formula C (CH 3 ) 3 OH. Graphically written these 

 formulas become 



H H H H 



I I I I 

 HO— C— C— C— C- 



i I I I 

 H H H H 



H H H 



HO— C— C— C— H 



I H H 

 H— C— H 



k 



-II 



(1) 



H 



I 

 H— C— H 



I H 



I 



HO C C— H 



( 2 > | H 



H— 0— H 



k 



■ (3) 



In many text-books these differences are expressed by some 

 such statement as : — " in the primary alcohol the OH group is 

 attached to a carbon atom which is itself attached to one 

 other ; in the secondary alcohol the OH group is attached to 

 a carbon atom which is itself attached to two others ; and in 

 the tertiary alcohol the OH group is attached to a carbon 

 atom which is itself attached to three other carbon atoms." 

 Such expressions as " attached to a carbon atom at the be- 

 ginning of the chain," "attached to a carbon atom in the 

 middle of the chain," &c, are also used when speaking of 

 isomerism. From these and similar expressions one might 

 conclude, as some of the opponents of the position theory 

 would almost appear to do, that the molecule is regarded as a 

 fixed structure, the different parts of which are rigidly ar- 

 ranged around a centre (just as one might stick balls of clay 

 on to stone), and that by removing one of the pieces which 

 compose this molecule and placing it in another fixed position 

 an isomeric molecule is produced. 



Language which would give any countenance to such crude 

 ideas as this should certainly not be made use of. The up- 

 holders of the position theory have given grounds for fault- 

 finding. But is the whole theory to be rejected because of 

 crudities in the manner of stating it ? 



That the structural and graphic formulas quoted above do 

 give to the chemist a very large amount of information con- 

 cerning the three butylic alcohols is patent to all ; and that 

 the main idea implied in them, viz. that the atoms composing 

 the molecules, although the same in kind and in number m 



I\J 2 



