Anecdotes of Painters, Engravers, Sculptors and Architects and Curiosities of Art (Vol. 3 of 3) by S. Spooner (best ebook reader under 100 TXT) 📖
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called Cleopatra's Needles; the other is still standing. The project of
removing it to London and erecting it in Waterloo Square, was
entertained for some time by the English government, but seems to have
been long abandoned; recently, however, an expedition is being fitted
out for the purpose.
CARBURI'S BASE FOR THE EQUESTRIAN STATUE OF PETER THE GREAT.
Milizia gives the following interesting account of the removal of the
immense mass of granite, which forms the pedestal or base of the
equestrian statue of Peter the Great, from the bogs of the Neva to St.
Petersburg, a distance of about fourteen miles. He also cites it as an
instance of extraordinary ingenuity and skill in mechanics. It is,
however, a much easier task to move a ponderous mass of rough, unhewn
rock, than a brittle obelisk, an hundred feet or so in length, requiring
the greatest care to preserve it from injury. It is also worthy of
mention, that in widening streets in New York, it is no uncommon thing
to see a three-story brick house set back ten or fifteen feet, and even
moved across the street, and raised an extra story into the bargain--the
story being added to the _bottom_ instead of the _top_ of the building.
Thus the large free stone and brick school-house in the First Ward, an
edifice of four lofty stories, 50 by 70 feet, and basement walls 2½ feet
thick, has been raised six feet, to make it correspond with the new
grade in the lower part of Greenwich-street. It is also no uncommon
thing to see a ship of a thousand tons, with her cargo on board, raised
out of the water at the Hydraulic Dock, to stop a leak, or make some
unexpected but necessary repairs.
"In 1769, the Count Marino Carburi, of Cephalonia, moved a mass of
granite, weighing three million pounds, to St. Petersburg, to serve as a
base for the equestrian statue of Peter the Great, to be erected in the
square of that city, after the design of M. Falconet, who discarded the
common mode of placing an equestrian statue on a pedestal, where,
properly speaking, it never could be; and suggested a rock, on which the
hero was to have the appearance of galloping, but suddenly be arrested
at the sight of an enormous serpent, which, with other obstacles, he
overcomes for the happiness of the Muscovites. None but a Catherine II.,
who so gloriously accomplished all the great ideas of that hero, could
have brought to perfection this extraordinary one of the artist. An
immense mass was accidentally found buried 15 feet in a bog, four miles
and a half from the river Neva and fourteen from St. Petersburg. It was
also casually that Carburi was at the city to undertake the removal of
Nature alone sometimes forms a mechanic, as she does a sovereign, ageneral, a painter, a philosopher. The expense of this removal was only
70,000 rubles and the materials left after the operation were worth
two-thirds of that sum. The obstacles surmounted do honor to the human
understanding. The rock was 37 feet long, 22 high, and 21 broad, in the
form of a parallelopipedon. It was cleft by a blast, the middle part
taken away, and in the cavity was constructed a forge for the wants of
the journey. Carburi did not use cylindrical rollers for his
undertaking, these causing an attrition sufficient to break the
strongest cables. Instead of rollers he used balls composed of brass,
tin, and calamina, which rolled with their burden under a species of
boat 180 feet long, and 66 wide. This extraordinary spectacle was
witnessed by the whole court, and by Prince Henry of Prussia, a branch
from the great Frederick. Two drums at the top sounded the march; forty
stone-cutters were continually at work on the mass during the journey,
to give it the proposed form--a singularly ingenious idea. The forge was
always at work: a number of other men were also in attendance to keep
the balls at proper distances, of which there were thirty, of the
diameter of five inches. The mountain was moved by four windlasses, and
sometimes by two; each required thirty-two men: it was raised and
lowered by screws, to remove the balls and put them on the other side.
When the road was even, the machine moved 60 feet in the hour. The
mechanic, although continually ill from the dampness of the air, was
still indefatigable in regulating the arrangements; and in six weeks the
whole arrived at the river. It was embarked, and safely landed. Carburi
then placed the mass in the square of St. Peter's, to the honor of
Peter, Falconet, Carburi, and of Catherine, who may always, from her
actions, be classed among illustrious men. It is to be observed, that in
this operation the moss and straw that was placed underneath the rock,
became by compression so compact, that it almost equalled in hardness
the ball of a musket. Similar mechanical operations of the ancients have
been wonderfully exaggerated by their poets."
COMPARATIVE SKILL OF THE ANCIENTS AND MODERNS IN MECHANICS.
Many persons suppose, and maintain, that the grandeur of the monuments
of the ancients, and the great size of the stones they employed for
building purposes, prove that they understood mechanics better than the
moderns. The least knowledge in mechanics, however, will show this
opinion to be erroneous. The moderns possess powers which were unknown
to the ancients, as the screw, and the hydraulic press, the power of
which last is only limited by the strength of the machinery. The works
of the ancients show that they expended a vast deal of power and labor
to gratify the pride and ambition of kings; but the moderns can do all
these things much easier, and in far less time, whenever they deem it
proper. There was nothing in ancient times to be compared with that
daring, ingenious, and stupendous monument of engineering skill--the
Britannia Tubular Bridge, across the Menai straits--projected, designed,
and built by Robert Stephenson, the famous English engineer. He had
previously built a similar but smaller structure--the Conway Tubular
Bridge.
THE BRITANNIA TUBULAR RAILWAY BRIDGE.
Had this stupendous fabric existed in ancient times, it would have been
regarded as the _first_ of the seven wonders of the world. Greater and
more expensive structures have been raised, but none displaying more
science, skill, and ingenuity, and none requiring such tremendous
mechanical power to execute.
The Britannia Tubular Bridge was built to conduct the Chester and
Holyhead Railway across the Menai Straits, to the island of Anglesea, in
the Irish Sea.
The difficulties which the engineer had to overcome, were greatly
augmented by the peculiar form and situation of the straits. Sir Francis
Head says, "The point of the straits which it was desired to cross,
although broader than that about a mile distant; preoccupied by Mr.
Telford's suspension bridge--was of course one of the narrowest that
could be selected, in consequence of which the ebbing and flowing
torrent rushes through it with such violence, that, except where there
is back water, it is often impossible for a small boat to pull against
it; besides which, the gusts of wind which come over the tops, down the
ravines, and round the sides of the neighboring mountains, are so
sudden, and occasionally so violent, that it is as dangerous to sail as
it is difficult to row; in short, the wind and the water, sometimes
playfully and sometimes angrily, seem to vie with each other--like some
of Shakspeare's fairies--in exhibiting before the stranger the utmost
variety of fantastic changes which it is in the power of each to
assume." The Menai Straits are about twelve miles long, through which,
imprisoned between the precipitous shores, the waters of the Irish Sea
and St. George's Channel are not only everlastingly vibrating, backwards
and forwards, but at the same time and from the same causes, are
progressively rising and falling 20 to 25 feet, with each successive
tide, which, varying its period of high water, every day forms
altogether an endless succession of aqueous changes.
THE TUBES.
The tubes forming the viaducts, rest upon two abutments and three piers,
called respectively the Anglesea abutment and pier, the Carnarvon
abutment and pier, and the Britannia or central pier, built upon the
Britannia rock in the middle of the straits, which gives name to the
bridge. The Anglesea abutment is 143 feet 6 inches high, 55 feet wide,
and 175 feet long to the end of the wings, which terminate in pedestals,
supporting colossal lions on either side, 25 feet 6 inches in length, 12
feet 6 inches high, and 8 feet broad, carved out of a single block of
Anglesea marble. The space between the Anglesea abutment and pier is 230
feet. This pier is 196 feet high, 55 feet wide, and 32 feet long. The
Carnarvon abutment and pier are of the same dimensions as those above
described, on the opposite shore. The Britannia pier is 240 feet high,
55 feet wide, and 45 feet long. This pier is 460 feet clear of each of
the two side piers. The bottom of the tubes are 124 feet above low water
mark, so that large ships can pass under them, under full sail.
There are two tubes, to accommodate a double track (one would have done
in this country, but in England they do nothing by halves), and each is
1513 feet long. The total length of the bridge is 1841 feet. These tubes
are not round or oval, but nearly square at the termini; the bridge
being constructed on the principle of the arch. A section of one of the
tubes at the Britannia pier is in the form of a parallelogram, where it
is 30 feet high, gradually diminishing towards each end to 20 feet. The
tubes are riveted together into continuous hollow beams; they are of
the uniform width of 14 feet 8 inches throughout; they are constructed
entirely of iron, and weigh about 12,000 tons, each tube containing 5000
tons of wrought iron, and about 1000 tons of cast iron. The tubes were
constructed each in four sections; the sections extending from the
abutments to their corresponding piers, each 250 feet long, were built
_in situ_, on immense scaffolding, made of heavy timbers for the
purpose, even with the railway; but the middle sections, each 470 feet
long, were built on piers on the Carnarvonshire shore, then floated into
the stream, and elevated to their position; each of these sections
weighed 1800 tons.
CONSTRUCTION OF THE TUBES.
The sides, bottom, and top of these gigantic tubes are formed of oblong
wrought iron plates, varying in length, width, and thickness, according
to circumstances, but of amazing size and weight. They are so arranged
as to obtain the greatest possible strength, the whole being riveted
together in the strongest manner. In addition to the 1600 tons of
wrought iron in each of the four large pieces, an additional 200 tons
was used to form lifting frames, and cast iron beams for the purpose of
attaching the tube to those huge chains by which they were elevated. The
construction of the tubes is thus described in the London Illustrated
News, from which this account is derived:
"In order to carry out this vast work (the construction of the tubes),
eighty houses have been erected for the accommodation of the workmen,
which, being whitewashed, have a peculiarly neat and picturesque
appearance; among them are seen butcher's, grocer's, and tobacconist's
shops, supplying the wants of a numerous population. A day school,
Sunday school, and meeting-house also conspicuously figure. Workshops,
steam-engines, store-houses, offices, and other buildings meet the eye
at every turn; one is led to conclude that a considerable time has
elapsed since the works were commenced, yet it is little more than two
years ago. A stranger, on coming to the ground, is struck with wonder
when for the first time he obtains a near view of the vast piles of
masonry towering majestically above all the surrounding objects--strong
as the pillars of Hercules, and apparently as endurable--his eyes wander
instinctively to the ponderous tubes, those masterpieces of engineering
constructiveness and mathematical adjustment; he shrinks into himself as
he gazes, and is astonished when he thinks that the whole is the
developed idea of one man, and carried out, too, in the face of
difficulties which few would have dared to encounter."
FLOATING OF THE TUBES.
The tubes were floated to the places whence they were elevated to their
positions on eight huge pontoons, fitted with valves and pumps to
exhaust the water from them, when all was ready to float the prodigious
iron beams. These pontoons or boxes were each 90 feet long, 25 feet
wide, and 15 feet deep. The pontoons having been placed under one of the
tubes (sections), the floating was easily effected, and the operation is
thus described by the "Assistant Engineer."
"The operation of floating the tubes (the four sections, and one only at
a time), will be
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