Ben -  Your pot has friends in Baltimore.  In the early 1980s we were doing
excavations near Pascault Row in Baltimore (near Lexington Market in city)
and found a large deposit of very similar vessels.  Hundreds were buried on
site....  They appear to have been same shape and size, but our lugs seem to
have been longer and have come more toward center (in comparison with your
picture).  The lugs had a very handmade, added-on look to them and vessels
were glazed on inside but not exterior.  All in all I would say they are
identical.  I left collection at University of Maryland at College Park when
I came to American University about a decade ago.  I don't know if any
examples are still extant?  Function is a problem....  We did identify a
perfume factory nearby, but the vessels found may have just been dumped
there and have no real historical conext in terms of immediate neighborhood?
 I suspect they are for some second half of 19th century idustrial process
and may have been base for some sort of "double-boiler" type apparatus
(something else sat inside?).  At any rate, that's the best I can do. If you
ever find anything else out about them, I'd be interested.

Joe Dent
American University