The diagnostic classification is based on the division of gases into two principal types a contemporary and ancient gases a and ... Considering in 1931 the classification of natural gases, Vernadskii [ l] wrote: aquot;A scientific classification is an empiric ... In other words, a classification interests us only so much as it answers practical needs in evaluation of phenomena. ... In studies of natural gases, the efforts of all investigators are directed on one hand toward a recognition of individual gasanbsp;...