19. In substances, both by showing and by defining.
III. Thirdly, for the explaining the signification of the names
of substances, as they stand for the ideas we have of their distinct species, both the forementioned ways, viz., of
showing and defining, are requisite, in many cases, to be made use of. For, there being ordinarily in each sort
some leading qualities, to which we suppose the other ideas which make up our complex idea of that species
annexed, we forwardly give the specific name to that thing wherein that characteristical mark is found, which we
take to be the most distinguishing idea of that species. These leading or characteristical (as I may call them) ideas,
in the sorts of animals and vegetables, are (as has been before remarked, ch. vi. SS 29, and ch. ix. SS 15) mostly
figure; and in inanimate bodies, colour; and in some, both together. Now,
