yond the Alleghanies and as far as the Rockies, a new science of
transportation was now to be learned--the art of finding the dividing
ridge. Here the first routes, like the "Great Trail" from Pittsburgh
to Detroit, struck out with an assurance that is in marvelous agreement
with the findings of the surveyors of a later day. The railways, when
they came, found the valleys and penetrated with their tunnels the
watersheds from the heads of the streams of one drainage area to the
streams of another. Thus on the Pennsylvania, the Baltimore and Ohio,
the Southern, the Chesapeake and Ohio, and other railroads, important
tunnels are to be found lying immediately under the Red Man's trail
which clung to the long ascending slope and held persistently to the
dividing ridges.

Even this necessarily brief survey shows plainly how that preeminently
American institution, the ridge road, came about. East and west, it
was the legitimate and natural successor to the ancient trail. With the
coming of the wagon, whose rattle was heard among the hills as early
as Braddock's campaign, the process of lowering these paths from the
heights was inevitably begun, and it was to the riverways that men first
looked for a solution of the difficult problems of inland commerce.
Eventually the paths of inland commerce constituted a vast network
of canals, roads, and railway lines in those very valleys to which
Washington had called the nation's attention in 1784.

CHAPTER III. The Mastery Of The Rivers

It would perhaps have been well, in the light of later difficulties and
failures, if the men who at Washington's call undertook to master the
capricious rivers of the seaboard had studied a stately Spanish
decree which declared that, since God had not made the rivers of Spain
navigable, it were sacrilege for mortals to attempt to do so.
Even before the Revolution, Mayor Rhodes of Philadelphia was in
correspondence with Franklin in London concerning the experiences of
European engineers in harnessing foreign streams. That sage philosopher,
writing to Rhodes in 1772, uttered a clear word of warning: "rivers
are ungovernable things," he had said, and English engineers "seldom or
never use a River where it can be avoided." But it was the birthright
of New World democracy to make its own mistakes and in so doing to prove
for itself the errors of the Old World.

As energetic men all along the Atlantic Plain now took up the problem
of improving the inl