Compound Molecules with Theoretical Atoms. 621 



of the line is evidently in equilibrium as far as the forces 

 along the length of the chain are concerned, being acted 

 upon by equal forces on either side. The framework of 

 hydrogen atoms keeps the carbon line from buckling, that is 

 keeps the carbon atoms in equilibrium in the other two 

 directions perpendicular to the chain. This great pressure 

 of the carbon atoms is, therefore, transmitted through the 

 chain to the end atoms, where it is balanced by the attraction 

 of the hydrogen atoms. The end hydrogen atoms are much 

 nearer to the carbon atoms than any other hydrogen atoms 

 in the molecule are, and on this account they are able to take 

 up the repulsion of the carbon atoms. This attractive force 

 is transmitted from end to end of the chain by the two zigzag 

 lines of hydrogen atoms, the one line below and the other 

 above the centre of the chain. On the sides the hydrogen 

 atoms are in almost stable equilibrium positions with respect 

 to each other, which produces a stiffening of the structure. 



It should i>e noticed that the height of the box forming 

 the chain is 359 units, being greater than the breadth, which 

 is 280, and that the length is greater than either, 489'5 units. 

 If some outside disturbing agency should tend to bend this 

 chain around in a direction perpendicular to the axes of the 

 atoms, the effect would be to attract all of the hydrogen 

 atoms over to one side of the box, while the repulsion between 

 the carbon atoms would tend to keep them from bending 

 around. If these hydrogen atoms were once flipped over, 

 so to spe.ik, they would tend to bring the ends of the chain 

 together and force the carbon atoms to follow until the ends 

 united into the form of a ring such as fig. 12, the carbons 

 remaining on the outside and the hydrogens forming two 

 rings, the one above and the other below the carbon ring. At 

 the same time the two atoms at the ends would be set free, 

 being no longer required to bind the structure together. 

 The zigzag lines under tension in the chain at the top and 

 at the bottom become the small hydrogen rings still under 

 tension in the ring form of molecule. 



The Benzene Ring, 



There is still another entirely distinct mode of formation of 

 compound molecules which is made possible by the fields shown 

 in Pls.Viri., IX., X., and XL In this system all of the atoms 

 are confined to one plane in distinction to those shown above, 

 which form solid figures. The basis of the system is the 

 compound C 6 H 6 , benzene, shown in fig. 14. The six carbon 

 atoms here form a sort of hexagon, but not a regular one. 



