The effect of the Gulf Stream on Ireland’s climate came up (it keeps winters mild enough, by and large, for palm trees and various other subtropicals to grow successfully). Here are a few links about that (the last one the best in my opinion, though it deals only glancingly with Ireland per se):
A snippet from “Earth and Sky”
From Coastal and Geodetic Survey Stories & Tales: including Benjamin Franklin’s early notes on the subject. (That man…there was nothing he wasn’t interested in. But then, as the excerpt shows, the subject came up in the couse of his business as Postmaster-General.)
A little earlier in the same article: Martin Frobisher says (in the 1570’s): ” Sayling toward the northwest parts of Ireland we mette with a great current from out the southwest, which carried us [by our reckoning] one point toward the northeastward of our said course, which current seemed to us to continue itself toward Norway and other of the northeast parts of the world, whereby we may be induced to believe that this is the same which the Portugese mette at Capo de Buong Speranza [Cape of Good Hope], where, stricking over from thence to the Straits of Megellan and finding no passage there for the narrowness of the sayde Straits, runneth alongue to the great Bay of Mexico, where also having a let of land it is forced to strike back again toward the northeast, as we not only here but 
in another place also further northward by goode experience this year have found.” The writer of the article adds: “How the currents returned to the Cape of Good Hope from the ‘northeast parts of the world’ is not stated, but the general course of the Atlantic system is very fairly laid out.”
…This could start to get fascinating, and I have work to do, so I should stop this now. To one side, though, you can see a thumbnail of Athanasius Kircher’s 1678 chart of the Gulf Stream in the south Atlantic: the first one made, apparently.
Meanwhile, it’s a chilly, blowy, wet morning: high winds roaring through the branches of the trees, heavy rain. I lit a fire and took a 
turn through the house to see where the cats are. All are scattered hither and yon in attitudes suggesting that no one in their right mind would be conscious during weather like this: that the only thing to do is sleep through it. Well, it’s nice that they can get away with it, but for my own part, I need to go make some tea and then get busy with Holiday. (And later, see what Peter did with the script last night. He was up till something like 5 AM with it.)
