with reference to this answer, tremolo notation,
It's not completely clear to me how one should interpret two bars placed on a half-note, in 4/4 (or 2/4) time. I'd always treated a two-bar marking as splitting the base-beat note into four pieces, so two bars on a half-note would mean playing sixteenths. However, some references such as dolmetsch indicate a double-slash half note to be played as eighth notes.
My particular concern in this case is the cello part to Dvorak's New World Symphony. What's the proper interpretation?