a mine of proportionable value we do not yet know. I was yesterday with an officer of the Army who farms a silver-mine for the State, who hath promised me what assistance he can in my mineral inquiries, and told me that a metallist and refiner whom he extolled with superlative elogies assured him that there was no country in Europe so rich in mines as Ireland, had but the inhabitants the industry to seek them, and the skill to know them.” But Robert Boyle was impatient to leave Ireland. “I live here in a barbarous country,” he told Clodius in this letter, “where chemical spirits are so misunderstood, and chemical instruments so unprocurable, that it is hard to have any hermetic thoughts in it and impossible to bring them to experiment.” In the autumn of 1654 he was back in England. In the previous year, during his flying visit to London, he had talked with Dr. Wilkins, of Wadham, about Oxford, and had probably ridden down to Oxford to see what it was like. Stalbridge was all very well, but it was removed from the by-paths of intelligence; somehow, since his illnesses, there was a sadness over its orchards which Vulcan himself could not dispel. London was a fascinating labyrinth of interests, but in Oxford he believed he could “live to philosophy.” Oxford was to be his Athens. Thither, already, some of the Invisibles had migrated from London. For it was no longer the old Royalist Oxford, where the sunburnt boy with the bow and arrows had once thought of joining the King’s Army. It was Oxford six years after the Parliament’s Visitation and Purgation; Oxford after the imposition of the Covenant. The old Heads had conformed or been summarily ejected, the new Heads were Commonwealth men; and Cromwell himself was Chancellor. It was an Oxford where the use of the Liturgy was not openly permitted. And yet, “speech is thrall, but thocht is free,” says the old Scottish proverb. At Oxford a man could still fast quietly, if he was so minded, for forty-one hours, without being sent down for it.[185] At Oxford one might still study philosophy, and mathematics, and Oriental languages unimpeded. And there was the Bodleian. Oxford was indeed “the only place in England where, at that time, Mr. Boyle could have lived with much satisfaction to himself.”[186] His horse would carry him between Oxford and London at any time: each night, on the road, he might lie under some hospitable roof of friend or relative, in mansions set in shady parks, amid flower-gardens and fishponds. And once in London, his sister Ranelagh’s door in the Old Mall was always open to him. And Gresham College, and Mr. Hartlib, and Mr. Clodius, and the rest of the Invisibles would receive him with ecstasy. The Hartlib family had moved to Charing Cross; and Hartlib and his “very chemical son” were excessively happy in their new abode.