hanged habitat and racial intermixture, is
furnished by the virility of the colonial peoples of our own day. The
receptiveness to new ideas and the rapidity of material progress of
Americans, South Africans and Australians are proverbial. No one doubts,
probably, that one or another of these countries will give a new
stimulus to the progress of civilization, through the promulgation of
some great epochal discovery, in the not distant future. Again, the
value of racial intermingling is shown yet nearer home in the
long-continued vitality of the British nation, which is explicable, in
some measure at least, by the fact that the Celtic element held aloof
from the Anglo-Saxon element century after century sufficiently to
maintain racial integrity, yet mingled sufficiently to give and receive
the fresh stimulus of "new blood." It is interesting in this connexion
to examine the map of Great Britain with reference to the birthplaces of
the men named above as being the originators of the inventions and
discoveries that made the close of the 18th century memorable as
ushering in a new ethnic era. It may be added that these names suggest
yet another element in the causation of progress: the fact, namely,
that, however necessary racial receptivity may be to the dynamitic
upheaval of a new ethnic era, it is after all _individual_ genius that
applies its detonating spark.

Nine periods of progress.

Without further elaboration of this aspect of the subject it may be
useful to recapitulate the analysis of the evolution of civilization
above given, prior to characterizing it from another standpoint. It
appears that the entire period of human progress up to the present may
be divided into nine periods which, if of necessity more or less
arbitrary, yet are not without certain warrant of logic. They may be
defined as follows: (1) The Lower Period of Savagery, terminating with
the discovery and application of the uses of fire. (2) The Middle Period
of Savagery, terminating with the invention of the bow and arrow. (3)
The Upper Period of Savagery, terminating with the invention of pottery.
(4) The Lower Period of Barbarism, terminating with the domestication of
animals. (5) The Middle Period of Barbarism, terminating with the
discovery of the process of smelting iron ore. (6) The Upper Period of
Barbarism, terminating with the development of a system of writing
meeting the requirements of literary composition. (7) The First Period
of