Scientific apparatus made from grates under ring (4,4)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

JARS (as a verb = grates = seems incongruous and/or unsettling) after (under, in a down clue) BELL (as in “give me a bell” = “give me a ring” = call me on the telephone). Bell-shaped glass covers used in scientific experiments.