Someone asked about whether butter bells work: the answer is, yes, they
do--but there is one drawback--the butter at the top of the bell (which is
on the bottom when the bell is in the part which contains the water) is
often wet from that water. I do have, and use, a butter bell, particularly
in the summer time, when butter can go rancid in no time flat. But in the
latest copy of the KA Flour catalog, they have a new, Polish, three-part
butter dish which has a water reservoir on the bottom, then a tray in which
you put the water, and finally a cover which goes over the whole
assemblage. I haven't personally tried one, but it looks as though it
would work, and it has the advantage of not getting any water on the
butter. Also, the butter bell requires you to soften the butter, and then
smush it into the bell, and that can be kind of tricky--the new dish takes
a whole, intact stick of butter, without requiring that it be reshaped in
any way.
Susannah