In this paper

an empirical equation

is proposed

for the relation of a series ofphysicochemical properties (P) and topological indexes (ZG) of normal para-ffins

asP=a1gZG/N~m+bwhere N is the number of the carbon atoms

the integer ZG is the sum of a setof the humbers P(G

k)

which is the number of ways in which such k bondsare so chosen from G that no two of them are connected

a

b

m are con-stants with property P.