Anecdotes of Painters, Engravers, Sculptors and Architects and Curiosities of Art (Vol. 3 of 3) by S. Spooner (pdf to ebook reader .TXT) 📕

Alexandria, one of the two obelisks

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, a

general, 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