Re. “there is no evidence I know of that Cavendish ever concerned herself with substantive proposals on this subject”

Indeed, in February 1668 Cavendish was actively solicited for contributions towards

the Building of a College upon the ground near Arundel-house given by the Honourable Henry Howard of Norfolk for that end

by the Royal Society’s “Register” at the time, Dr. William Croone.

Although it was called a “College” in the 200 printed subscription forms sent to potential contributors, the purpose-built scientific institute planned by leading Royal Society figures such as John Wilkins was, from its conception in the years around 1660, intended exclusively for the study of nature and the arts. As such, it would be devoted to research and discussion rather than teaching (as were colleges at Oxford, Cambridge, and Gresham).

Given her recent visit to the Royal Society in May 1667, her intellectual relationships and close personal ties with various Royal Society Fellows, and her string of publications on scientific matters, Margaret Cavendish was included among the council’s short list of eminent “well disposed persons” who, while “not of the society” themselves, were believed to have an interest in assisting “a work of such public usefulness.”

Benefactors were to have their names registered in a lavish volume bound in gilt-stamped vellum and inscribed “Contributions towards Building the College,” and thereby, in the words of Henry Oldenburg when writing a similar letter of solicitation to Paul Rycaut (then the English consul in Smyrna and an absentee Fellow),

perpetuated to all posterity, as they shall well deserve, that doe assist according to their severall Abilitys, to render England the Glory of the Western World, by making it the Seat of the best knowledge, as well as it may be the Seat of the greatest Trade.

(Oldenburg, letter to Rycaut of 30 January 1668; qtd. in Michael Hunter, Establishing the New Science, 169)

Curiously, although Cavendish and her husband both gave endowments to Trinity College (Cambridge) in the 1660s, the duchess of Newcastle did not subscribe to a College for the Royal Society as requested. Other aristocrats and statesmen associated with the fledgling Royal Society similarly failed to respond to this or any other of the Society’s requests for help, prompting Michael Hunter’s claim that

This dichotomy therefore exposed with special clarity the Society’s rather pathetic illusions about the intent of the aristocratic sponsors — the traditional patrons of intellectual activity — who had allowed their names to be added to the Society’s roll.

(Hunter, Establishing the New Science, 163)

Cavendish did, however, bring out seven editions of her works in 1668, including the new title, Plays, never before Printed, which contained The Convent of Pleasure. We will never know now how much Cavendish’s redesign of a public scientific institute along the lines of a privately-held, feminized Convent of Pleasure owed to Dr. Croone’s epistolary stimulus. As far as I know, his letter to her has not survived, and neither institutional vision was brought to fruition.