Did it also mean an impossible one?
Yet Katie would prefer showing her Ann to Mrs.Prescott than to Zelda Fraser.

Zelda, the fashionable young woman, would pounce upon the absence of certain little tricks and get no glimmer of what Katie vaguely called the essence.

Might not Mrs.Prescott find the reality in the possibilities?
"It comes to this," Katie suddenly saw, "I'm not shamming, I'm revealing.

I'm not vulgarly imitating; I'm restoring.

The connoisseur should be the first to appreciate that." It turned her off into one of those long paths of wondering, paths which sometimes seemed to circle the whole of the globe.