Ken,

I should think that if the reference to leading beards is cosmetological, the
lead would more likely be a whitener (like powdering one's wig) than a
darkener.  But I don't do it either way, being a firm (and simultaneously
flabby) believer in the notion that trying to outwit mother nature is asking
for trouble.  If it's not cometological, Cod only knows what weird things
they did back in the olden days when people know how to build real buildings
(when did Trollope write? 1840's-50's?) instead of getting Dryvit in their
hair.

Ralph