The Sun.
London, England, 1864-04-11 00:00:00

RUSSIAN ARMOUR-PLATES.

On Saturday afternoon the first of a series of
enormous iron bars, ordered to be rolled by the
Millwall Iron Company for the Russian Govern-
ment
for the construction of a powerful iron fort at
Cronstadt, was rolled most successfully in the pre-
sence of a large number of visitors. It is now some
years since efforts have been made to induce our
own and various Governments to sanction the adop-
tion of iron instead of granite in important land
forts; but it is only recently, and since the con-
struction of the ironclads have proved the value of
the system, that the proposal has been entertained.
Armour-plates of immense thickness are now being
made at Messrs. Brown and Co.'s Works at Sheffield
for the Belgian Government, to be used in the
construction of some additional iron defences at
Ant werp. France, it is said, intends similar works
on all the more important points of Cherbourg's
sea defences, and now Russia has ordered the
materials for an iron fort at Cronstadt. The enor-
mous advantages which iron possesses over stone,
not alone in its utter impregnability, but in allowing
the guns the widest range while limiting the open-
ing of the embrasure to little more than the width
of the muzzle of the ordnance, has long been seen,
and the general adoption of iron for land defences
has only been checked by the difficulties of manu-
facturing sueh enormous masses sound throughout.
But, with the experience gained in the manufacture
of our armour-plates, the great foundries through-
out the kingdom are improving every day, and con-
tracts are now eagerly sought for which, four years
ago, every firm would have refused, as requiting
manufacturing impossibilities. The bars rolled at
these works on Saturday, however, were in advance
again upon what has been hitherto done, and the
result was looked forward to with some doubt,
for each bar when delivered was to weigh six tons,
to be 15 inches square, to be tongued and grooved
in the roiling, and to be perfect in its soundness
throughout. The furnaces were opened at 3 o'clock
and the immense mass of metal was drawn forth on
to an iron truck, heated to a brilliancy that was
almost binding in:;its intense whiteness, and in-
stantly changing the temperature of the vast fac-
tory to a scorching sulphurous heat that was insup-
portable. Directly it was out, workmen, shielding
their faces as they best could, swept :,he impurities
from its surface with long brooms soaked in water,
but which eevertheless lit like tow the instant they
came in contact with the iron, which was sparkling
like a gigantic firework. It was then let down the
incline to where the rollers, turned by one of the
largest fly-wheels in the kingdom—mere than 100
tons weight, and nearly 401 t. in diameter—we s
waiting to crush the mass into its required form.
This was the critical moment; for au instant or
two the rollers failed to grip it, but at last they
caught it, and the whole machinery moved slower,
as amid loud cheers frem the workmen they began

,o wind it in. As it was slowly crushed through,

the refuse melted iron was squirted out in showers
in all directions, and as the mass emerged from the
rollers on the other side it lit up everything with a
bright, lambent flame, said to be caused by the pres-
sure to which the bar was subjected. This was
only the first roll, but it had to be passed through
three times to reduce it to its proper thickness. It
was toot, however, as in the case of ordinary armour-
plates, a mere question of reduction, as these bars
have to be rolled, tongued, and grooved to fit into
each other. Thus in the rolling they have to over-
come all the peculiar difficulties of their construction
almost in two operations, which must be done while
is in a half melted state, or the whole is spoilt. The
bars, as we have said, are 15 inches square, but each
of these presents a most difficult section. In the
first place the lower part of the bar has a projecting
rib, and in the upper part is a groove, corruspond-
ing in size with the rib on the lower half, so that
the projection of one bar may fit into the groove of
the one beneath, thus making a solid dove-tailed
wall of iron. Beyond these, also, is a rid at the back

of the bar, formed to dovetail again into projecting

masses of iron in the rear supports of the fort, and
in the process of rolling all these departures from a
plane and smooth suthca have to be formed, and to
be formed with so much accuracy that each part fits
into the other without the necessity cf any machine
Planing of surfaces. To give to the mass of metal
the required section the rollers of the mill are
grooved where the raised surface is required, and
sunk to produce the projecting ribs. It took three
rolls on Saturday before all was finished, and at the
completion of each the workmen, who seemed in-
tensely interested in the success of the experiment,
cheered 'loudly. The last operation was effected by
lifting the bar into a bed, so to speak, made be-
tween two masses of iron, and then passing over it
an enormous iron roller, which removed the curved
form the bar had received in passing between the
rollers. Now that the success of the first bar has
been achieved, the rolling of the others will go on
every day until the whole order is completed. When
the fort is erected in Russia it is intended to test

its powers of resistance with a gun throwing a shot
of a thousand pounds weight, which is in a short
time to be cast in Prussia for the Imperial Govern-
ment. In the calibre of its ordnance Russia seems
making a great effort to keep ahead of the rest of
Europe, and is most liberal in its orders for the
largest guns in any country which will undertake
to manufacture for it. But in the calibre of its
ordnanc3 Europe is now as it ever has been far be-
hind America. At Pittsburg, in Pennsylvania, a
50.t0n gun has just been successfully cast for the
United States' Government. This monster piece of
ordnance, which is stated to be perfect in its cast-
ing, is to throw a solid 20 inch shot weighing
1;600ib.

After the rolling of the bars on Saturday the visi-
tors were conducted over the whole of the extensive
smithries, machine shops, and shipbuilding depart-
ments of the company's works. The Northumberland,
iron-clad frigate, the fine model of which formed so
prominent a feature in the late Exhibition, attracted
considerable attention, and especially her enormous
sternpost —one forging of more than 60 tons weight.
An ironclad cupola ram, in course of construction
for the Italian Government, was noticed on account
of the intense ugliness of its outline and the for-
midable offensive qualities of. its projecting beak.
The immense iron c(,lumns for the new Blackfriars-
bridge, and the cylinders used by the engineers of
the London, Chatham, and Dover Railway in build-
ing up the piers of the bridge, were also shown to
the visitors. Some of the iron plates rolled at the
Millwall Works, classed A 1, and which have been
fired at in some of the experiments, showed, by the
deep indentations on their surface, how perfect had
been their manufacture and how great their powers
of resistance.

Mr, Glaisher's Eighteenth Balloon Ascent
from Woolwich Arsenal, April 6.

TO THE EDITOR OF THE SUIT.

Sir,—The balloon left the earth at 4h. 7m. p.m, ;
in three minutes it was I,oooft. high, and moved
very evenly upward, at the rate of I,oooft. in three
or four minutes, to the height of 11,000 ft. at 4h.
38m.; it descended at the rate of 500 ft. per minute)
till we were within 1,500 ft. of the earth at 4h. 59m. ;
we then descended very slowly, were I,oooft. high
at 51. 4m., and reached the ground at sh. 18m; We
were accompanied by our friend Mr. F. Norris, who
has been up with us on several occasions.
During the whole day the sky was overcast, and
the wind was from the S.E. ; on leaving we at once
crossed over the river to Essex; at the height of
500 ft. the air was very misty, and the view very
limited, but Woolwich Dockyard, the town of
Woolwich, the river under us, the numerous ship-

ping, with so many upturned faces from their decks,
formed a very pleasing and interesting sight. The
mist increased in density as we rose. When at
2,500 ft. we entered a dense white cloud, and shortly
afterwards lost sight of the earth; at 3,500 ft. there
was a very thin fine rain ; at 4,000 ft. the clouds
were less in density, and there was a great increase
of light ; at 4,boOft. we saw the sun faintly, but
there was more cloud above; at 5,000 ft. the sun
cast a faint shadow, but we were still in cloud,
which decreased :.in density as the balloon rose.

When at B,looft. high we felt the wind press against
us with a sensible pressure, and interred that there
was another change of the wind, but we had no
means whatever of determining the direction from
which it came; the mist again increased till the
height of 9,000 ft. was reached ; we here heard
a train and supposed we were over the Chelms,
ford lino of railway. At the height of 9,500 ft.
the sun shone very brightly, and it was
quite warm ; at 10,000 ft. we were entirely out of
cloud, and there was a sea of white cloud dazzling
in its brightness, extending without a break or irre-
gularity in its surface as far as we could see all
round—that is, for more than 100 miles on all sides.
Near to us on the cloud, on the side opposite to the
sun, was a bright oval halo of immense extent, in
the centre of which was situated the shadow of the
balloon and car, but without prismatic colours ; this
all appeared to revolve with us, for it was constant,
and we knew we were turning round by the su❑
now shining at our backs and then in our faces ; at
the greatest elevation (11,000 ft.) there was perfect
repose, the sky was without a cloud, and of a beau-
tiful deep blue. We were, however, quite baffled
in our attempts to determine our direction, as we
could not see any inclination in the grapnel line.
Mr. Coxwell had been watching the weather all

day, and once during a break in the lower clouds he
had sent up a pilot balloon, which had moved to-
wards the east when at a high elevation, and, con-
necting this with the current we had met with, he
had begun to fear that the railway we had beard
might b 3 the Southend railway, end, if so, we were
drifting out to sea. He therefore determined to
take a dip downwards without delay, before attempt•
ing a higher elevation, so that if we found ourselves
over water we might have gas enough to keep up
for some time. We began the dip downwards, the
sky continued of a deep blue, the air free from-mist,
and the sue hot, till we approached the height of
7,000fc. and at 6,000 ft. we lost sight of the sun, and
were in a dense white cloud at 5,500 ft. high ; when
at 3,000 ft. fine rain fell and we caught sight of the
earth at the height of 2,500 ft. ; we expected to find
ourselves over Essex, but hills and a beautiful tine
dulating country presented themselves, and it was
evident we were at fault.

_ _ •
Mr. Coxwell then decided upon anchor:tag, and we
did so on the outskirts of a pine plantation, near
Sevenoaks, in Kent, on the estate of the Marquis
Camden, and we found the direction of the wind
here S.E., the same direction as at starting. The
temperature of the air was 46 deg. on leaving, at
the height of I,oooft it was 411 deg., at 1,500 ft it
wis 40 deg., at 2,000tt, 37 deg.; at 3,000 ft it was
34 dek; from 3,500 ft to 4,000 ft there was no var:a-
tion from 33 deg.; this was the lowest temperature
met with; at 5,000 ft the temperature increased to
36 deg., and did not change for 500 ft, then decreased
to 34 deg. at 6,500 ft, at which point it turned to
increase, and was 40 deg. at B,oooft ; it decreased
to 34 deg. again at the height of 9,000 ft ; it then
increased, on leaving the cloud below, to 36 deg. at
11,000 ft, and rapidly to 46 deg. while between
10,000 ft and 11,000 ft high. The highest tempera-
ture observed was at 8,600 ft, on descending, when
it was 47 deg.; from this point the temperature de-
clined, on descending, to 40 deg., at 1,500 ft high,
being nearly the same as on ascending, and to 46
deg. on the ground.
The temperature of the dew point, or that tem.,
perature at which water, in the invisible shape of
vapour, is deposited as water on substances of that
temperature, was 7 deg. below that of the air on
leaving the earth, and this difference was the same
up to 2,000 ft. It then decreased to 1 deg. on enter-
ing the cloud, and was from 1 deg. to 3 deg. while
in the dense cloud. On leaving it at B,ooolt this
difference suddenly increased to 10 deg., and varied
from 14 deg. to 24 deg. between the heights of
8,000 and 11,000 feet, and decreased on again en-
tering the cloud to 5 deg. and 6 deg.
There were 21 grains of water in a cubic foot of
air near the ground, about two grains in the cloud,
and about one grain only above the cloud.
The humidity of the air, therefore, increased from
the earth to the centre of the cloud, where it was
all but saturated, and decreased rapidly above the
cloud, where it was very dry.
No ozone was detected by Schonbein, MofLt, or
Lowe's papers during the whole time the balloon was
in the air.
The lines in the solar spectrum were very nume-
rous and well defined. The spectrum itself was very
long.

The goat was very uneasy, and continued bleating
till we passed through the cloud and into a warmer
atmospheae, when it was quiet and happy.
This ascent was intended to have reacted to five
miles high,
but in ascending from London or Wool-
wich, MI. Coxwell's tactics are put to the severest
tests, especially
if the sky be overcast as it was on
this day, although the visible mass of vapour floated
away in a north-westerly direction ; yet some indi-
cation during the day led Mr. Coxwell to conclude
that there was an upper westerly current, and it was
this induced him to descend. It is impossible to say
how far we went into Essex, where we re-crossed
the Thames, or how far we penetrated into Sussex,
or if we reached Sussex at all; but it is certain that