Can any of the brick experts here tell me when bricks first started to be made with holes in them? I ask as I'm currently rebuilding part of one of our fireplaces and a previous repair has been done with parts of this sort of brick. This in itself doesn't surprise me too much, it is just that it is being held into position with lime mortar so this suggests that it has been there some while. Other work in the house has been done in cement so this patch of lime is out of place.
(The brick is the standard red - it is just a bit lime stained)
(The brick is the standard red - it is just a bit lime stained)