GR translation: on the maniac side of the 18th century

[Mike Jing]

V79.20-25, P81.1-7    . . . the lilting Hungarian gypsy-whisper bashing
like tambourines all around the room, provoking, in one way or another,
everyone here except for the aged Brigadier himself, who just goes rambling
on from the pulpit of what was a private chapel once, back there on the
maniac side of the 18th century, and is now a launching platform for “The
Weekly Briefings,” . . .

Which time period does "on the maniac side of the 18th century" refer to
exactly? And why was it "maniac"?