Definition of "subtile"

And sometimes this perception, in some kind of bodies, is far more subtile than the sense; so that the sense is but a dull thing in comparison of it: we see a weather-glass will find the least difference of the weather, in heat, or cold, when men find it not.

1819, Francis Bacon, The Works of Francis Bacon, volume 2, page 2

I burst into mirth at this—I liked him even better when he was subtile than when he was simple.

1888, Henry James, chapter 2, in The Solution