Brunelleschis Dome (17 page)

After these tools had shaped the block into its proper geometrical profile, the surface of the stone was given three or four separate polishes. The first polish involved using an iron plate to rub a sharp sand across the stone, thus removing the irregularities of the surface. The second used a finer sand, or sometimes dust from a whetstone, and the third used rottenstone, an abrasive red limestone powder known as
tripoli
. The final polish was performed with a putty made from tin oxide. So burnished, the marble would be as smooth as glass.

Dressing the marble at the quarry had the advantage of lower transport costs, for only the finished stone was shipped to Florence, not the heavier and more ungainly rough-hewn blocks. Yet moving the stone intact over long distances and across rough terrains was by no means an easy process. If they passed inspection, the blocks were raised from the quarry with hoisting tackle and conveyed down winding roads on carts — two delicate operations — until they reached the busy town of Carrara, whose cathedral and principal buildings all were built from gleaming
bianchi marmi
. After export taxes were paid, they were carted several more miles to the old Roman port of Luni, on the malaria-ridden coast. Here they were moved across the beach on wooden rollers, lifted onto barges by means of a treadwheel crane, then launched into the waters of the Ligurian Sea. This leg of the journey was particularly perilous, as was discovered in 1421 when one of these barges sank during a storm with a loss of its cargo, a load of
bianchi marmi
destined for the cornice on the dome’s rain gutter. After a 25-mile sea voyage, the boat would reach the mouth of the Arno, up which the cargo was transported over sandbars and shoals toward Florence.

The Opera was able to defray the expense of bringing marble from Carrara by offering some of it for sale as tombstones to the wealthier citizens of Florence. But at times marble tombstones originally destined to glorify deceased magistrates and wool merchants became part of the cupola instead. In July 1426 there was a shortage of good marble due to the high transport costs, causing the Opera to order the cutting up of tombstones — presumably those from a stockpile rather than ones already marking graves. But by that time it was clear that a cheaper and more expedient method of acquiring this precious stone was needed. And Filippo, ambitious and inventive as ever, had just the plan up his sleeve.

Water transport was considerably cheaper than overland carriage, which was prey to the vagaries of the terrain and the weather, the moods and endurance of beasts of burden, and the frailty of wagons. It was, for example, twelve times more expensive to transport grain by land to Florence than along the Arno.
¹
But water transport to Florence was made difficult by the Arno’s capricious flow, the volume and rate of which was highly variable, depending on the season and the weather. The fifty-mile stretch from Florence to Pisa was badly silted and, in the hot summer months, little more than a trickle. Unlike, say, the river Thames, the Arno had virtually no tide on which a vessel might ride. Galleys rowing to and from Pisa were sometimes forced to winch themselves forward with the help of trees along the riverbank. In periods of heavy rain the Arno was even more impossible. During the
piena
, the spring flood, it became a frenzied torrent.Water hurtled down from the slopes of the Apennines, eroding its banks, smashing bridges, and inundating both Florence and Pisa with monotonous regularity. Even under ideal conditions, flat-keeled barges could travel upriver only as far as the port of Signa, still ten miles from the gates of Florence, because of the shallow water and numerous sandbanks. As a result, all cargo bound for Florence had to be transferred to mules or carts and padded with straw-filled sacks for the final stretch.

Various attempts were made to solve the problem of the Arno’s fickle currents. Silt was scraped from its bed by dredgers — rigged with treadmills powering buckets or scoops fixed at the end of long shafts. But with each flood the silt returned. Riverbanks pulverized by floodwaters were shored up with the wrecks of old galleys, but these were always liable to drift away again. In 1444, in one of his last acts as a civil engineer, Filippo would fortify the bank of the Arno near the Porto San Marco in Pisa. Decades later, and most ambitious of all, Leonardo da Vinci planned to bypass the clogged artery of the Arno altogether by constructing a 50-foot-wide canal that would leave the Arno near Florence and run through Prato and Pistoia, 25 miles to the northeast, before swinging south and rejoining the river at Vicopisano, a few miles upstream from Pisa. This venture, like most of Leonardo’s plans, was never carried out.

But in 1426 Filippo had in mind a different solution to the problem of river transport. An innovator in countless other areas, he had also received, in 1421, the world’s first ever patent for invention.
²
Describing the
capomaestro
as “a man of the most perspicacious intellect, industry and invention,” this document granted him a patent of monopoly for “some machine or kind of ship, by means of which he thinks he can easily, at any time, bring in any merchandise and load on the river Arno and on any other river or water, for less money than usual.”
³
Until this point no patent system existed to prevent an inventor’s designs from being stolen and copied by others. This is the reason why ciphers were so widely used by scientists and also why Filippo was so reluctant to share the secrets of his inventions with others. Filippo complained about this plagiarism to his friend Mariano Taccola in a bitter diatribe against the ignorant multitude:

Many are ready, when listening to the inventor, to belittle and deny his achievements, so that he will no longer be heard in honourable places. But after some months or a year they use the inventor’s words, in speech or writing or design. They boldly call themselves the inventors of the things that they first condemned, and attribute the glory of another to themselves.
⁴

The patent for invention was designed to remedy this situation. Possibly Filippo already had in mind a cheaper and more effective means of shipping marble up the Arno; but the patent makes clear that the invention would have a wide application, being of great benefit “to merchants and others.” Once built, this curious-looking vessel quickly became known as
Il Badalone
,“the Monster.” According to the terms of the patent, any boat copying its design, and thereby violating Filippo’s monopoly, would be condemned to flames.

Not much is known about the precise design of
Il Badalone
, the finer points of whose construction Filippo, despite the protection of his patent, kept secret for fear of imitators. Manetti and Vasari do not even mention the episode, which does not exactly redound to their hero’s glory. However, it must have been technologically novel and adventurous to have been deemed worthy of a patent. The nickname implies a great and perhaps even ungainly size, which would have been one of the boat’s chief economic advantages — and possibly also the source of its undoing.

The only picture we have of the boat was done by Mariano Taccola, to whom the
capomaestro
, in a rare fit of candor, appears to have described its construction. In his book
De Ingeneis
Taccola shows how a wagon with fourteen wheels that transports the marble overland from the quarry can be converted into a raft tugged by a rowboat. We know that in 1427 Filippo borrowed from the Opera a rope with which to tow
Il Badalone
. It is therefore very likely that the boat consisted of a large, raftlike wooden platform possibly buoyed by a number of floats, such as barrels, and tugged along the river either by another boat or by oxen toiling up the towpath. But even Taccola, a skilled engineer, appears to have been flummoxed by the design: he attempts a description of
Il Badalone
only to find that his pen fails him.“Let it be known that one cannot explain each and every detail,” he writes in some frustration. “Ingenuity resides in the mind and intelligence of the architect rather than in drawing and writing.”

Whatever the boat’s design, its first and only known employment was the shipment of marble for the ribs of the dome. One year after the Opera had been forced to use tombstones in its building, Filippo acquired a contract to transport 100,000 pounds of white marble from Pisa. With his ingenious new boat he calculated that he would reduce the shipping cost by almost half, lowering it from 7 lire and 10 soldi per ton to 4 lire and 14 soldi.

Taccola’s version of
Il
Badolone
.

Not everyone was so optimistic.
Il Badalone
appears to have been a source of ridicule from the start, a stick which Filippo’s enemies, temporarily overawed by his astonishing success with the dome, now gleefully used to beat him. Most vocal of these was his old adversary Giovanni da Prato, who composed a sonnet attacking Filippo and his latest invention, which he described scathingly as an
acque vola
,“water bird.” This description implies that
Il Badalone
, rather like a Mississippi steamboat, may have featured paddle wheels, the sight of which, thrashing in the water like an awkward pair of wings, could have inspired Giovanni’s insulting nickname. Such paddle wheels, powered by treadmills, were certainly at a design stage a few years later.

Giovanni’s ill-humored piece of verse makes his earlier comments regarding the faulty profile of the dome seem positively tame by comparison. He not only mocks the famous
capomaestro
as a “pit of ignorance” and a “miserable beast and imbecile,” but furthermore promises to commit suicide should Filippo’s plan succeed. Filippo was not one to suffer such discourtesies in silence. He may not have been a man of letters of the same stature, but he was no stranger to literary pursuits, as his study of Dante proves. He composed a sonnet of his own, equally caustic, in which he derided his distinguished opponent as a “ridiculous-looking beast” who was incapable of understanding the mysteries of nature in his — Filippo’s — ingenious designs. These exchanges became so rancorous that a short time later Filippo was among the citizens of Florence made to swear an oath to “forgive injuries, lay down all hatred, entirely free themselves of any faction and bias, and to attend only to the good and the honor and the greatness of the Republic, forgetting all offences received to this day through passions of party or faction or for any other reason.” It was an oath that, in the years to come, Filippo would find difficult to keep.

A sketch of a boat with paddle wheels by the Sienese inventor Francesco di Giorgio.

In the end, Giovanni da Prato was not required to carry out his grisly promise to kill himself. Problems taxed the enterprise from the start. Although the patent was granted in 1421,
Il Badalone
did not make her maiden voyage for another seven years, by which time the patent, originally for three years, had needed to be renewed at least once. In the summer of 1426 Filippo traveled to Pisa to confer with the consul of maritime affairs regarding the heightening of the city’s fortifications. It seems likely that he took the opportunity to negotiate over
Il Badalone
, for the consul of maritime affairs inspected boats and merchandise passing through Pisa and issued permits for all crafts using the Arno.
Il Badalone
was possibly even built in Pisa, which had long been renowned for its shipwrights. The galleys of the new Florentine navy — the first of which had sailed for Alexandria in 1422 — were at that time under construction in its dockyards. In any case, one day in early May 1428 Filippo’s revolutionary new boat, laden with 100 tons of white marble, was launched from the dock at Pisa, in the shadow of another, leaning, technological folly.

It is not clear whether disaster struck because of a design flaw, the Arno’s treacherous sandbanks and currents, or some other mishap: the precise details of
Il Badalone
’s fate have not been recorded. We do know that the boat not only failed to reach Florence but did not even make Signa. It either sank or became stranded near Empoli, 25 miles from Pisa, with the loss of its entire load. Shortly thereafter anxious officials from the Opera notified Filippo that he was “required within eight days . . . to ship by small boats to the Opera that quantity of white marble which he had shipped on the
Badalone
from the city of Pisa to Empoli.”