Silicon adhesive works very well. However it all depends on what
kind of stress and/or bearing these pieces may have on each other or
separately.
I doubt doubt for an instant that adhesives have improved massivle in the
last 100 years. However, for historical (hysterical?) reasons I'll
include a little bit from "Watch and Clockmakers' Handbook, Dictionary
and Guide" by F. J. Britten. Mine is the 10th editon, 1902. If yoy are
repairing some antique object, you may want to use the methods that were
used when it was originally made.
'Mending Marble Clock Cases -- Plaster of Paris may be used, but it is
bette, especially if the mended part is visible, to soak the plaster of
Paris in saturated solution of alum, and then bake it. It is used with
water, may be mixed with any desired colouring material and will take a
high polish. Lime and white of egg make the best cement for closely
fitting surfaces, but it requires using very quickly as it so soon sets.
Marble case makers use a cemetn composed of Russian tallow, brickdust,
and resin melted together, and it sets as hard as stone at ordinary
temperatures'.
-tony