ch towns must have clearly defined limits
of population, _dependant finally on the minimum yearly produce of the
district they control_. If ever they rise above that limit the natural
checks of famine, and of pestilence following enfeeblement, will come
into operation, and they will always be kept near this limit by the
natural tendency of humanity to increase. The limit would rise with
increasing public intelligence, and the organization of the towns would
become more definite.

[15] I owe the fertilizing suggestion of this general principle to a
paper by Grant Allen that I read long ago in _Longman's Magazine_.

[16] It is worth remarking that in 1801 the density of population in the
City of London was half as dense again as that of any district, even of
the densest "slum" districts, to-day.

[17] Be it noted that the phrase "available area" is used, and various
other modifying considerations altogether waived for the present.

[18] Their temporary suppression of the specialist is indeed carried to
such an extent that one may see even such things as bronze ornaments and
personal jewellery listed in Messrs. Omnium's list, and stored in list
designs and pattern; and their assistants will inform you that their
brooch, No. 175, is now "very much worn," without either blush or smile.

[19] The present system of charging parcels by the pound, when goods are
sold by the pound, and so getting a miserly profit in the packing, is
surely one of the absurdest disregards of the obvious it is possible to
imagine.

III

DEVELOPING SOCIAL ELEMENTS

The mere differences in thickness of population and facility of movement
that have been discussed thus far, will involve consequences remarkable
enough, upon the _facies_ of the social body; but there are certain
still broader features of the social order of the coming time, less
intimately related to transit, that it will be convenient to discuss at
this stage. They are essentially outcomes of the enormous development of
mechanism which has been the cardinal feature of the nineteenth century;
for this development, by altering the method and proportions of almost
all human undertakings,[20] has altered absolutely the grouping and
character of the groups of human beings engaged upon them.

Throughout the world for forty centuries the more highly developed
societies have always presented under a considerable variety of
superficial differences certain features in common. Alw