The Sun.
London, England, 1857-11-23 00:00:00

LAUNCHING OP BIG; SHIPS.

The following letter has been addressed to a con-
temporary
SIR,--The difficulties and dangers incidental to
the launching of the Great Eastern are essentially
inherent to the sliding system, as applied to the
launching of ships of so extraordinary a bulk.

The real interest that I take in the success of an
undertaking which, it is to be hoped, will contribute
to the progress of navigation as well as to the
honour of England, prompts me respectfully to au b-
mi t, through your influential columns, a system of
launching founded on different principles.
It substantially consists in floating down the great
ship from her actual place to the river, through a
temporary lock of colossal dimensions, yet of an
easy and comparatively cheap construction. This
sort of lock should be formed with piles rising to a
sufficient height above the ground, with sail canvas
spread against them. Water should be introduced
with steam pumps till the ship can float and be
hauled close to the river aide of the lock. Theu by
lifting up a part of the canvas a portion of the in-
side water is let out, and a level is established be-
tween it and the river at high water time. Agate
Is now opened by lowering a few piles and props,
which were not driven into the ground, but simply
screwed, and leaning to lower and firmer supports,
opposite either to the s! em or the sterm. Through
t his opening the vessel may be longitudinallyhauled
out into the broad Thames.

In 1843 I made an extensive set of experiments,
in the canal of Bologna, and in the river Rene, on
this system as applicable to preventing or stopping
inundations. Several useful applications of this
hydraulic system have since been made in Italy—
one of them even in the river Po. It may possibly
not be amiss if I add a few general statements.
The leogth of the canvas must be greater than
the length of the row of piles to be covered ; for
the horizontal section must consist of a series of
convex circular arcs, in all the iutervala between
the piled. The ratio of 10.7 is nearly the most,
proper. The breadth, also, or height of the sail,
must be greater than the inten led height of the
water ; because not only the canvas should rise
more or less above it, but it wants also a consider-
able superabundance at the lower hem. When the
water is flowing through the row of piles, if you
wish to cut it off, fasten the upper hem of the sails
at the top of the piles, then spread the sail over the
water, and let it drop. As Buenas the water begins
to he higher ou the inside of the sail, the pressure
brings it close to the piles, and to all the sinuosities
of the bottom of the river, in an admirably regular
and prompt manner, so that the water soon pre-
cludes altogether the issue to itself. When a suffi-
cient extent of sail is overlapped to another sail
properly supported, or to the embankment of the
river, tee pressure fattens it sufficiently, without
sewing or any other provision.
The strength of the canvas must be in the coin-
pound ratio of the height of the water and of the
radius of curvature of the canvas in the intervals
between any two piles. The diameter of the piles,
if isolated, must be in the compound ratio of the
height of the water and of the distance between the
centre of each pile and that of the next ; the
depth to which it is driven must be in the
ratio of the height of the water. A row of
fir piles, driven three yards deep into a soil of
ordinary consistence, with 9-inch diameters at the
ground section, at the mutual distance of one yard
from centre to centre, and with ordinary sail can-
vas applied to them, can well stand he pressure of
water as high as three yards, and a little more. If
the water is to be held considerably higher, the
canvas must be stronger or double, and the inside
piles properly strengthened with one or more rows
of piles, connected with them through horizontal
and inclined props.
Under the peculiar circumstances of the Great
Eastern, instead of erecting the rivereAde row of
piles to the great height of 14 yards, which would
be nearly requ'red to float down the vessel imme-
diately to the river, it might be found easier, as
well as cheaper, to subdivide the space and the ope,
ratiou into three successive stages.

If the launching succeeds with the means already
tried, so much the better ; if not, I am confident
the method which I have had the honour of placing
before you might satisfactorily answer. At all
events, my modest and well meant suggestion may
possibly find some other useful application.--I
am, &c., L. FILOPANTI.
(Late Professor of Hydraulics at Bologna.)

ADVERSITY.—SureIy we deceive ourselves to think ou
earth continued joys would please. It is a way that crosses
that which nature goes. Nothing would be more tedi-
ous than to be glutted with perpetual jollities. Wore the
body tied to one dish always—though of the most exqui-
site flavour it could make choice of—yet, after a small
time it would complain of loathing and satiety ; and so
would the soul, if it did ever epicure itself in joy. Dis-
contents are• sometimes the better part of our life. I
know not well which is the most usefitl ; joy I may
choose for pleasure, bat adversities are the best for profit;
and sometimes those do so far help me, as I should with-
out them want much of the joy I have.