at the Royal Institution, 1 900-1 907. 375 



metric behaviour and is in harmony with the fact that it is a coloured 

 substance. It will be noticed that in this formula the carbon atoms 

 are united partly as they are in the paraffins (on the one side of the 

 central ring), partly as in ethene, partly as in benzene. Attention 



is called to these various formula3 in order that it may be clear that 

 when a number of carbon atoms become associated they are neces- 

 sarily arranged in a variety of ways. 



Amorphous carbon itself is presumably but the last stage in a 

 series of transformations, the end result being a complex in which a 

 considerable, if not a very large, number of ring systems are so inter- 

 locked that the various affinities are all engaged. But to account for 

 the properties of amorphous carbon, it is necessary to assume that 

 ethenoid affinities — the unsatisfied conjoined pairs of affinities formed 

 by the union of two carbon atoms by the partial saturation of two 

 affinities of the one by two affinities of the other — preponderate in 

 the molecule and come freely to the surface. 



It may be pointed out that, when oxidised, naphthalene yields 

 phthalic acid — an acid derived from benzene, thus — 



COOH 



COOH 



Naphthalene 



Phthalic acid 



Anthracene also gives rise to this acid on oxidation. Obviously, 

 if two other systems such as that attached to one pair of carbon atoms 

 of the centric nucleus in anthracene were attached to each of the 

 remaining two pairs of carbon atoms in the same nucleus, a hydro- 

 carbon would be formed capable of giving rise on oxid ation t o an 

 acid of the formula — 



