ABSTRACT
Much of the current panorama of chemical theory has been erected on foundations that are essentially grs^h-theoretical in nature. Chemical graphs are now bdng used for many different purposes in all the major branches of chemistry. The present widespread usage of the chemical graph renders the origins of the earliest implicit application of g r^ h theory of some considerable interest. Chemical graphs were first introduced in the latter half of the eighteenth century. To understand the need for them at that time and the circumstances of th d r introduction into the chemical literature, it will be necessary to say something about the prevailing attitudes in dghteenth century chemistry. Chemical thinldng in the eighteenth century was steeped in Newtonian ideas, especially those pertaining to the internal structure of matter and the short-range forces existing between particles. In 1687 Newton himself had stated [14] that all natural phenomema depend “upon certain forces by which the particles
of bodies, by some causes hithero unlmown, are dther mutually impelled towards one another, and cohere in r^n la r figures, or are repelled and recede from one another.”
