Full of hope from these promising reports, on 3rd May Galileo arrived at Rome with the MS. of his “Dialogues.” And events during his two months’ stay seemed to realise his expectations. Soon after his arrival he had a long audience of Urban VIII., and wrote on 18th May in high spirits to Florence:—“His Holiness has begun to treat my affairs in a way that permits me to hope for a favourable result.”[225] Riccardi also met Galileo, as was to be expected from Castelli’s letters, in the most obliging way. Galileo showed him his work with the express request that he would examine it closely. The papal censor, however, could not but perceive, with all his personal regard for Galileo, that in his “Dialogues” he had by no means always kept, _de facto_, within the limits of hypothetical treatment of the Copernican system, and in some parts had far exceeded them. He decided, therefore, both as his official duty and in the interest of Galileo himself, to have the book altered to the hypothetical standpoint. Many corrections were to be made, and both preface and conclusion were to be altered so as to agree with them. Riccardi intrusted the first task to his official assistant, Father Rafael Visconti, who seemed well qualified for it in his capacity of professor of mathematics. He executed it with equal prudence and ingenuity, improved many passages, and finally approved the work thus revised.
The middle of June had meanwhile arrived, and Galileo was anxious to leave Rome on account of the heat. But Riccardi wished to look through the “Dialogues” once more after they had been revised by Visconti, before giving them his _imprimatur_. Galileo represented that this second revision was not customary, and succeeded in inducing Riccardi _to grant permission for the printing for Rome_.[226]
On the other hand, Galileo undertook to fashion the beginning and end of the work in accordance with a plan of the supreme authorities of the censorship. There were also still a few passages to be personally discussed with the author; and as he was unable to stay longer at Rome without danger to his health, which was already beginning to suffer, it was agreed that he should return in the autumn, and meanwhile[227] he would prepare the index and the dedication to the Grand Duke, and revise the preface and conclusion. The main condition, however, under which Riccardi gave the book his _imprimatur_, was that after its final completion it should be submitted to him; and in order to avoid loss of time, he engaged to look it through sheet by sheet, and to send each at once to press after inspection. As was usual in the case of members of the Accadémia dei Lincei, the work was to be published in the name of this society, and the president, Prince Cesi, was to see it through the press.