to himself and satisfaction to his countrymen. During his stay in
England he was elected a fellow of the Royal Society. He soon after paid
this society the compliment of dedicating to it his Latin poem, entitled
_De Solis et Lunae Defectibus_ (London, 1764). This prolix composition,
one of a class which at that time was much in vogue--metrical epitomes
of the facts of science--contains in about five thousand lines,
illustrated by voluminous notes, a compendium of astronomy. It was for
the most part written on horseback, during the author's rides in the
country while engaged in his meridian measurements. The book is
characterized by G.B.J. Delambre as "uninstructive to an astronomer and
unintelligible to any one else."

On leaving England Boscovich travelled in Turkey, but ill-health
compelled him soon to return to Italy. In 1764 he was called to the
chair of mathematics at the university of Pavia, and this post he held,
together with the directorship of the observatory of Brera, for six
years. He was invited by the Royal Society of London to undertake an
expedition to California to observe the transit of Venus in 1769; but
this was prevented by the recent decree of the Spanish government for
the expulsion of the Jesuits from its dominions. The vanity, egotism and
petulance of Boscovich provoked his rivals and made him many enemies, so
that in hope of peace he was driven to frequent change of residence.
About 1770 he removed to Milan, where he continued to teach and to hold
the directorship of the observatory of Brera; but being deprived of his
post by the intrigues of his associates he was about to retire to his
native place, when the news reached him (1773) of the suppression of his
order in Italy. Uncertainty as to his future led him to accept an
invitation from the king of France to Paris, where he was naturalized
and was appointed director of optics for the marine, an office
instituted for him, with a pension of 8000 livres. He remained there ten
years, but his position became irksome, and at length intolerable. He
continued, however, to devote himself diligently to the pursuits of
science, and published many remarkable memoirs. Among them were an
elegant solution of the problem to determine the orbit of a comet from
three observations, and memoirs on the micrometer and achromatic
telescopes. In 1783 he returned to Italy, and spent two years at
Bassano, where he occupied himself with the publication of his _Opera
p