meter. After the suppression of the Jesuits
Father Boscovitch was made Director of Optics for the Marine, a post
created for him in order to secure his services for France.

During the second period of the history of the Vatican Observatory at
the end of the eighteenth and the beginning of the nineteenth century,
the upper story of the Gregorian tower was fitted up with
meteorological and magnetic instruments with a seismograph, a Dolland
telescope, a small transit instrument and a pendulum clock and a
series of very careful observations on a number of subjects made. From
1800 to 1821 Gilii made an uninterrupted series of meteorological
observations, reading the instruments twice a day, at 6 a.m. and 2
p.m. The observations are published for seven years and the rest are
preserved as manuscripts in the Vatican Library. There are also
deposited astronomical observations of eclipses, comets, Jupiter's
satellites and of a transit of Mercury. Gilii laid down the meridian
line in front of St. Peter's with the obelisk as a gnomon and the
readings of the seasons by the length of the shadow. To him are due
also the bronze marks on the floor of St. Peters, giving the
comparative lengths of the greatest churches of the world. It was he
who placed the first lightning rod on the cupola of St. Peter's. The
{479} heavens, the weather, the lightning are supposed often to be set
by religiously inclined persons particularly under the care of
Providence, to be influenced by prayer, yet these are exactly the
three departments of science that were faithfully followed in their
detailed scientific aspects during all the centuries by the Papal
Astronomers under the patronage and with the approval of the Popes,
with the avowed purpose of discovering the natural laws under which
they occur.

Two of the distinguished teachers of mathematics and astronomy of the
end of the eighteenth century at Rome were Father Thomas Leseur,
professor at the Sapienza, and Professor Franz Jacquier, professor at
the Roman College, who wrote a commentary on Isaac Newton's
_Principia_ which did much to popularize Newton's work.

When, because political influence was brought to bear very strongly on
the Pope, the Jesuits were suppressed in 1773, the Roman College
passed from their hands and the real reason for allowing the Vatican
Observatory on the Papal grounds to fall into disuse was manifest, for
the Popes at once took up the question of re-establishing their o