7355 miles.
In 1856 23,242 miles.

Thus from 1830 to 1840, the rate is as 2167/41 or 53 nearly; from
1840 to 1850, 7355/2167, or 3 nearly; and from 1850 to 1856, 23242/
7355 or 3 nearly; and from 1850 to 1860 we may suppose the rate will
be about 4. The rate is probably now at its permanent maximum,
taking the whole country together,--the increase in New England
having nearly ceased, while west of the Mississippi it has not
reached its average.

Among the larger and more important roads and connected systems in
our country may be named the New York and Erie Railroad,--connecting
the city of New York with Lake Erie at Dunkirk, (and, by the road's
diverging from its western terminus, with "all places West and South,"
as the bills say,)--crossing the Shawangunk Mountains through the
valley of the Neversink, up the Delaware, down the Susquehanna, and
through the rich West of the Empire State.

The Pennsylvania Central Road: from Philadelphia through Lancaster
to Harrisburg, on the Susquehanna, up the Juniata and down the
western slope of the Alleghanies, through rock-cut galleries and
over numberless bridges, reaching at last the bluffs where smoky
Pittsburg sees the Ohio start on its noble course.

The Baltimore and Ohio Railroad: from Baltimore, in Maryland, to
Wheeling and Parkersburg, on the Ohio;--crossing the lowlands to the
Washington Junction, thence up the Patapsco, down the Monocacy, to
the Potomac; up to Harper's Ferry, where the Potomac and the
Shenandoah chafe the rocky base of the romantic little town perched
high above; winding up the North Branch to Cumberland,--the terminus
of the Chesapeake and Ohio Canal, and of the great national turnpike
to the West, for which Wills' Creek opened so grand a gate at the
narrows,--to Piedmont the foot and Altamont the summit, through
Savage Valley and Crabtree Gorge, across the glades, from which the
water flows east to the Chesapeake Bay and west to the Gulf of Mexico;
down Saltlick Creek, and up the slopes of Cheat River and Laurel Hill,
till rivers dwindle to creeks, creeks to rills, and rills lose
themselves on the flanks of mountains which bar the passage of
everything except the railroad; thence, through tunnels of rock and
tunnels of iron, descending Tygart's Valley to the Monongahela, and
thence through a varied but less rugged country to Moundsville,
twelve miles below Wheeling, on the Ohio River.

These are our three great roads where eng