The Sun.
London, England, 1857-09-03 00:00:00

dicator, which sank suspended to the lead, the one
being a creek on the other, so tiit no error of
moment could avoid detection. In no event could
the depth be greater than the azruount of line out,
while owing to deflecting causes affecting the line
alone, Ma,.sey's indicator might with perfect accu-
racy read considerably less. During the first half
of the cruise care was taken to obtain the precise
depth with the line, with the most gratifying agree-
ment of its returns with the readiness of the self-
registering sounding apparatus. As in every case,
however, the readings of the latter were preferred,
it was found convenient to throw out a supera-
bundance of line to assure the descent of the lead to
the bottom • the amount of line out wts thus often
in considerable excess of the re:iordei depth. Two
sets of soundings were thus obtained ; ono with
Maßiey's apparatus, and the other with the odd
moth,xl of simple line and sinker. That the former
is to bi preferred is argued by the fact that specimens
from the bottom being obtained every time, the
depth could not have been in excess of the length
of line out, while it might, have bees as much less
as the readings on Massey's apparatus, the sounding
line being deflected from the perpendicular by
driftage and currents,- and that these causes of error
really exist is admittiAl by Maury in a dozen places.
The imperfections of the system he advises arc pro-
digioug, and when overcome ar3 the exceptional
cases ; not one-tenth of -the deep-sea s -,endings ob-
tained under it are considered reliable by Maury
himself. At a depth of one mile or two miles,- with
no currents or driftings, it may be trusted. These
conditions were apparently perfectly obtained by
Captain Plitt, of the Albany, in the Gulf of
Mexico ; yet, sounding twice at the same point, the
returns differed one-half. But these conditions arc
hardly ever obtained. The ocean is full of currents,
which will carry off the sounding line in immense
.leops ; and in the immense ocean depths, where
the shock of the sinker striking bottom cannot be
zonveyel through two or three miles of line, it be-
' comes almost impossible to arrive at an approxima-
tion of its true depth. Two boundiogs at the same
spot will differ 50 and 100 per cent. It is tbis
im-
potent manner of obtaining soundings that has fos-
tered the vulgar belief in the unfathomable depth
of the sea. However great are these causes of error,
they are not applicable to the little self-registering
sounding apparatus used on board of the Arctic.
It may have errors of its own: but it escapes these:;
and on the precision of its returns will depend, in
no small degree, the success of failure of the At-
lantic Telegraph.

THE ROYAL ALBERT BRIDGE AT

SALT el 51L

and flags—this excellent arrangement obviating
any of the old plan of shouting out the orders or
sending missages. Each vessel stationed bore a
distinguishing number.
At a very early hour in the morning there were
strong indic dions that the inhabitnnts of the three
towns intended to make the occasion a grand and
general
,hiliday. From about 10 o'clock in the
.shoring till
.three in the afternoon, six statners
were constantly running from Devonport to Salt-
ash, without the least intermission, conveying to
Saltash during the day nearly 10,000 persons. The
railway also brought a large number of persons to
the neighbourhood. At noon the greater number
of the shops closed, and shortly after thousands
ware seen wending their way to the point of at-
traction, where ultimately some persons estimated
t at nearly 100,003 persons mast have assemb'ed.
The Devonport Dockyard was closed at 12 o'clock,
and most ef the officera and artisans were among
the spectators.
The townspeople of Saltash also, not to be be-
hind hand in expressing their joy and mirth on so
festive an occasion for their interests, suspended
flags in Various parts of the town, and the merry
peal of the church bells enlivened the scene
throughout the afternoon. A large number of
yachts, vessels, and boats, many of them gaily de-
coratedwith flags, were also on the river, and
every avadalde station on the surrounding hills
was occupied by spectators. Several tents and
marquees wore erected to afford accommodation to
them. The weather was most genial, and the scene
altogether presented such a lively coup d'ceil as is
seldom witnessed in that vicinity. Along the
Devon side, of the river were ranged a row of
itinerant refreshment stalls and confectioners'
stands ; a few shows were also present. The pub-
lic-houses, beershops, and tea-houses in the neigh-
bourhood were also densely crowded.
Atie.s in the afternoon, the whole of the prepa-
rdtions having. been completed, the pontoons glided
into the river. Just under the tube, in the centre
of the roadway, a platform was erected, which was
occupied by Mr. Brunel and part ofthe staff of his
engineering department. There were about 500
men on board the vesesls and ashore employed in
the operation, and kept busily at work, especially
those on board No. 4, station vessel, whose assist-
ance was required for a longer period than the
others. The arrangements were so admirably con-
ducted that not the least irregularity occurred, or
the least noise or confusion prevailed. As the mt s-
sive structure moved round towards its destined po-
sition everybody gazed on it With admiration ; aud t he
mechanical skill ana ingenuity of the engineer, Mr.
Brunel, was the sole subject of conversation. About
half-past 3 o'clock the western end of the tube was
placed in its position, amidst the cheers of the thou-
sands of spectators that were present. The band of
the Royal Marines- were placed on board asteamer,
near the tube, and throughout the afternoon playel
a variety of musical pieces, which greatly enlivened
the proceedings. The tube and roadway chains,
stn.:Us, &c., present a most unique appearance ; at
once a memorial of engineering ingenuity, and the
t iumph-of mechanical science, as applied to practi-
cal purposes of great difficulty. It is believed that
several months will be occupied in raising this sec-
tion vertically to its permanent place on a line with
the railway. From its present position it will be
gradually raised, as circumstances will allow, by
means of hydraulic presses.
About 5 o'clock the band played the National
Anthem, and the spectators began to disperse, the
steamers being again crowded on their return passage.
A large number of private and public carriages and
equestrians were at the passage during the after-
noon, but we are happy to say that notwithstanding
the numbers present awl the magnitude of the un-
dertaking, not the slightest accident occurred dur-
ing the day.