New-York daily tribune. [volume] (New-York [N.Y.]) 1842-1866, 1851-10-24
Tlree-decked Man-OEWG Steamers.--


An interesting experiment Is IN PREPARATION al '"e
seapor, ofToulon. TIE French Government mas
ordered an engine of4Oo horse power to &c pu' ID"
the man -of-war Napoleon, Of one hundred guns
calculated that ths machine will propel the vessel al
tie speed Of eigh. miles ar hour The atiemp' is
looked upon with considerable interest IN France
and England. II successful II VIII be inflated IN
other ships.
Length of Rulways.-The total num-
Der Of miles Of railway now III operation a50Oo, OF
which there are in the United States lo2o0 miles IN
CUBA 300 miles in Great Britain 6,Jco miles IN
Belgium 200 miles in France 800 IN Spain CO.
&c Comparing these numbers With the population,
there are for each inhabitant in the United States 81
feet of railroad and in Cuba 10 feet, in Grea. Britain
70 feet III Belgium feet IN France feet IN Spain
inches.
Dring. Vessels. Mr.. Cave, the owner
and manager OF one cf the first iron workshops IN
Pans, Is now building two large boats to De used UNI
der water in the work Of clearing away the bar at
the mouth of the Nile They are on new plan.
and better than anything of the kind we have heard
Of In the middle of the deck Is a large circular
hole going vertically through the ship, and II 1t
slides cylinder reaching 10 the bottom of the river,
telescope. Above the opening is large air chamber
% feet in diameter and 10 feet high. BY forcing
compressed air into the air chamber the water in the
tube IS driven out at the lower end, leaving dry
portion of the bed An apparatus of the same kind,
but on reduced scale, is nov in operation on the
ryeISeine.
Enforcement IN Rd,lrOdds-We have
lately seen announced plan to increase the power
of traction locomotives, by pressing them against
the rails by means of an artificial oadstone. We
permitted to describe recent discovery, which the
inventors hope TO render still more perfect, and
which is just the Of the above. II consists
in reducing the friction Of the cars on the rails 10
mere nothing by electric battery, so arranged as
to raise and very nearly suspend them in the air--a
perfect suspension being only prevented by the ne
cesslty of a slight pressure to maintain the cars on
the track. The inventors design first to apply their
process to the transportation Of passengers and they
expect travel at the rate Of eghty miles an hour,
with less expense and greater safety than is now
done at IS miles Their rails in the form, and
not weighing more than seven pounds TO the foot,
are supported by wooden pillars, like lamp-posts, at
an elevation of feet above the ground, and feet
apart. The cars only q feet wide, but 80 feet long,
are suspended between them upon wheels OF
small diameter fOlllhg, OF course, uiOh we tpP
OF the rails. IT the two extremties OF each
car and in the middle, at a sufficient distance from
the wheels are attached powerful magnets made of
an immense number of reels of wire, wound around
pieces Of soft iron, the poles placed directly below
the rails, and near them as practicable. The
effect is easily understood As soon the wires
are united TO pile to form circuit, the magnets ex-
ercise powerful attraction on the rail but this
being immoyabe, the magnet itself obeys the attrac-
ton, and the car attached following the slight pres
sure which It still exercises on its wheels IS Just
equal to its weight minus the attractive power Of
the magnets It may be observed that electricity
IN this arrangement will not cos; much. IL is no.
used as motive power but static pressure 1t does
not consequently, become exhausted, and may be
continued without much expense. This invention
is very good in principle. We cannot yet Judge
whether it has been sufficiently elaborated to be
practicable The first invention above alluded to, to
press locomotives against rails, is not worth much,
in our opinion, to apply to common locomotives,
which may, without difficulty, be made weighty
enough for any labor required of them but in con-
necton with the second invention, it is invaluable,
as it allows the use of locomotives at least as light
as the cars themselves and this is of great import
ance when the structure does not stand upon solid
ground
Colored DdguerreOtypeS.- This import
ant discovery appears to have been made simulsa-
neously in America by Mr.. Hill. and in France by
Mr.. Niepce. Specimens have been exhibited here
and there, but no clear explanation of the process
has been made known in either country.
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