This is the quotation I was scrabbling for before.
The old orchard and the herb garden beyond it had been so silent, so
freighted with oblivion, that they recalled to me the Atrium of Time,
and Valeria with her exquisite face warmed in furs.
Claw, chapter XXIII, opening words
Apart from the first reaction `Not thinking about women again?', this shows just the associations I was trying to suggest for the Atrium. The Atrium doesn't travel in time, which implies darting back and forth, materialising in 1970s Britain to defeat the Sea Devils, materialising in 19th Century Britain to defeat horrible things in the sewers, materialising in 1980s... well, you get the picture. It remains fixed in time, unmoving (remember the carved animals?), while all else travels forward. Of course, we know it has seasons, but that's just the stuff it's fixed with respect to. (It's OK, I don't understand that either.)
Wolfe probably means `atrium' to have something like the classical meaning (is there a Peristylium of Time?), but the word, in modern parlance, means something like a big reception area, not unlike a Wolfean Antechamber, where you wait and wait and nothing happens.
corncrake