multitude of things there is no resemblance, except the fact of being
considered as parts of one whole, as 'the world,' or 'the town of
Nottingham' (meaning its streets and houses, open spaces, people, and
civic organisation), the term denoting them as a whole is Singular; but
'the world' or 'town of Nottingham,' meaning the inhabitants only, is
Collective.

In their strictly collective use, all such expressions are equivalent to
singular terms; but many of them may also be used as general terms, as
when we speak of 'so many regiments of the line,' or discuss the
'plurality of worlds'; and in this general use they denote any of a
multitude of things of the same kind--regiments, or habitable worlds.

Names of substances, such as 'gold,' 'air,' 'water,' may be employed as
singular, collective, or general terms; though, perhaps, as singular
terms only figuratively, as when we say _Gold is king_. If we say with
Thales, '_Water is the source of all things_,' 'water' seems to be used
collectively. But substantive names are frequently used as general
terms. For example, _Gold is heavy_ means 'in comparison with other
things,' such as water. And, plainly, it does not mean that the
aggregate of gold is heavier than the aggregate of water, but only that
its specific gravity is greater; that is, bulk for bulk, any piece of
gold is heavier than water.

Finally, any class-name may be used collectively if we wish to assert
something of the things denoted by it, not distributively but
altogether, as that _Sheep are more numerous than wolves_.