ilippo ran short of money and
contrived to make this good by setting jewels of price for certain
goldsmiths who were his friends; and thus he was left alone in Rome, for
Donato returned to Florence, while he, with greater industry and labour
than before, was for ever investigating the ruins of those buildings.
Nor did he rest until he had drawn every sort of building--round,
square, and octagonal temples, basilicas, aqueducts, baths, arches,
colossea, amphitheatres, and every temple built of bricks, from which
he copied the methods of binding and of clamping with ties, and also of
encircling vaults with them; and he noted the ways of making buildings
secure by binding the stones together, by iron bars, and by
dove-tailing; and, discovering a hole hollowed out under the middle of
each great stone, he found that this was meant to hold the iron
instrument, which is called by us the ulivella,[18] wherewith the stones
are drawn up; and this he reintroduced and brought into use afterwards.
He then distinguished the different Orders one from another--Doric,
Ionic, and Corinthian; and so zealous was his study that his intellect
became very well able to see Rome, in imagination, as she was when she
was not in ruins. In the year 1407 the air of that city gave Filippo a
slight indisposition, wherefore, being advised by his friends to try a
change of air, he returned to Florence. There many buildings had
suffered by reason of his absence; and for these, on his arrival, he
gave many designs and much advice.

[Footnote 18: This was probably something like the modern lewis.]

In the same year a congress of architects and engineers of the country
was summoned by the Wardens of Works of S. Maria del Fiore and by the
Consuls of the Guild of Wool, to discuss methods for raising the cupola.
Among these appeared Filippo, giving it as his advice that it was
necessary, not to raise the fabric directly from the roof according to
the design of Arnolfo, but to make a frieze fifteen braccia in height,
with a large round window in the middle of each of its sides, since not
only would this take the weight off the supports of the tribunes, but it
would become easier to raise the cupola; and models were made in this
way, and were put into execution. Filippo, being restored to health
after some months, was standing one morning in the Piazza di S. Maria
del Fiore with Donato and other craftsmen, when they began to talk of
antiquities in connection wit