the 5th of July 1859. He was the author
of numerous inventions, including the cagniardelle, a blowing machine,
which consists essentially of an Archimedean screw set obliquely in a tank
of water in such a way that its lower end is completely and its upper end
partially immersed, and operated by being rotated in the opposite direction
to that required for raising water. In acoustics he invented, about 1819,
the improved siren which is known by his name, using it for ascertaining
the number of vibrations corresponding to a sound of any particular pitch,
and he also made experiments on the mechanism of voice-production. In
course of an investigation in 1822-1823 on the effects of heat and pressure
on certain liquids he found that for each there was a certain temperature
above which it refused to remain liquid but passed into the gaseous state,
no matter what the amount of pressure to which it was subjected, and in the
case of water he determined this critical temperature, with a remarkable
approach to accuracy, to be 362 deg.C. He also studied the nature of yeast and
the influence of extreme cold upon its life.

CAGNOLA, LUIGI, MARCHESE (1762-1833), Italian architect, was born on the
9th of June 1762 in Milan. He was sent at the age of fourteen to the
Clementine College at Rome, and afterwards studied at the university of
Pavia. He was intended for the legal profession, but his passion for
architecture was too strong, and after holding some government posts at
Milan, he entered as a competitor for the construction of the Porta
Orientale. His designs were commended, but were not selected on account of
the expense their adoption would have involved. From that time Cagnola
devoted himself entirely to architecture. After the death of his father he
spent two years in Verona and Venice, studying the architectural structures
of these cities. In 1806 he was called upon to erect a triumphal arch for
the marriage of Eugene Beauharnais with the princess of Bavaria. The arch
was of wood, but was of such beauty that it was resolved to carry it out in
marble. The result was the magnificent Arco della Pace in Milan, surpassed
in dimensions only by the Arc de l'Etoile at Paris. Among other works
executed by Cagnola are the Porta di Marengo at Milan, the campanile at
Urgnano, and the chapel of Santa Marcellina in Milan. He died on the 14th
of August 1833, five years before the completion of the Arco del Sempione,
which he designed for his n