M — Just back from a short camping holiday in Brittany, and this reply of yours has brightened up my day, spent so far unpacking, washing, and cleaning. Thanks. Until now the silence on this topic was becoming rather deafening.

I was looking through Silber & Fleming (1880s) recently and noticed similarly proportioned jugs described as
Water Jugs listed with both wine and spirit decanters (i.e. water as a mixer rather than water as a drink, like lemonade). I don't know where Mark West found his description, but he has been around a long time so I am sure has a good contemporary source.
Whatever, it is almost certainly not a claret jug.
Bernard C.
