The following is from Mary Geiter's "The Restoration Crisis and the Launching of Pennsylvania, 1679-81":
In April 1679 Charles made the first move to neutralize the opposition by forming a new Privy Council with the Earl of Shaftesbury as its president. Although the news was greeted with "joyful bonfires" in the City, the verdict had still to be given as to "whether we are landing upon New Atlantis or only in the view of old Brasile."
The footnote for this phrase states it was found on the back of a list of names for the new Privy Council.
What exactly is meant here by New Atlantis and old Brasile? I can gather that new Atlantis is hopeful of some ideal that this council will bring about, but old Brasile doesn't make a whole lot of sense to me. My guess is "same old shit," but why that specific phrase?
The statement is literary allusion. " The New Atlantis" was a work by Francis Bacon published in 1626 as a philosophical fable about a visit to an ideal island in the Pacific Ocean and the social conditions there.
Brasile, or Brasil, or Hy-Brasil was a name used for fictitious islands off the West coast of Ireland, from folklore and sometimes equated with Greek mythology as the "Isles of the Blest". The significant point here being that although sometimes seen they are unattainable, fading away when approached. The word "Old" is used in contrast to "New" Atlantis.
So the phrase means approximately "The verdict is out on whether we are coming into a new political ideal or whether the promise of it will just fade away as we approach."
See The Oxford Companion to English Literature for an explanation of the terms.