184 Heilbron
mixed mathematicians and natural philosophers engaged included (to
choose a few stereotypes) French engineers, British agriculturalists, clerics
in and out of Italy, and German bureaucrats.
The natural knowledge to which the Paris Academy and the Royal So-
ciety devoted themselves aroused great interest in the wider society when
administered in homeopathic doses. It gave people something to talk
about. A large literature, usually arranged in dialogues, gave instruction
in natural- philosophical conversation. The earliest and most successful
of these manuals, Fontenelle’s Entretiens sur la pluralité des mondes, eaves-
drops on a beautiful marquise and her handsome young tutor, who stroll
through her gardens on summer evenings discussing cosmology. Fon-
tenelle was an homme de lettres—a poet and playwright—before becoming
a full- time natural philosopher. That he did in 1699, on the reformation
of the Paris Academy of Sciences, which chose him as its permanent sec-
retary. His duties were to publish the papers of the academicians, preface
their annual Mémoires with a précis of their most important results, and
celebrate each in turn, when his turn came, in an eloquent obituary no-
tice. Although Fontenelle ventured a work or two on mathematics, his
role as natural philosopher was organizational and rhetorical. He owed his
appointment to the clarity and eloquence of his writings—which shows
suffi ciently his distance from most academics of our time.
Fontenelle’s imitators included Francesco Algarotti and the abbé Noël
Antoine Pluche, whose Spectacle de la nature (Nature Displayed) has a count
and countess as instructors, a young nobleman as their tutee, and no math-
ematics or method. Pluche had learned that “mathematical Discourses,
or a chain of Dissertations... frequently satiate and disgust”; therefore
he chose interlocutors for their ability to “furnish conversation.”^29 Like
Pluche, Algarotti ruled out mathematics as giving a work “too scientifi c
an Air.” Also like Pluche, he purveyed natural philosophy to help “polish
and adorn Society.” And like Fontenelle, to whom he dedicated his New-
tonianismo per le dame, he took his dialogue from conversations between a
beautiful and witty noblewoman and a stand- in for himself. They talked
and basked under the summer sun at a villa overlooking Lake Garda.^30
In sunless England the parlor became as full of talk about natural phi-
losophy as about the weather. When Sir Richard Steele saw the fi rst orrery
in the workshop of its maker in 1716, he immediately perceived its im-
portance as a centerpiece of conversation. Even the dullest of his country-
men, he said, could learn the elements of astronomy from it in an hour
and have natural- philosophical conversation for a lifetime. “This one con-
sideration should encite any numerous Family of Distinction to have an
Orrery as necessarily as they would have a clock.”^31 Many English intro-