ST. IVES

Loosely derived from Robert Louis Stevenson's last, unfinished novel, these adventures of a roguish captain (Barr) in Napoleon's army leap briskly -- if less than rollickingly -- from boudoir conquests to sword fights and pistol duels to daring escapes over hill and dale. But the movie is perhaps best enjoyed as a slyly witty, subtly ribald romance. ''Drink me, quaff me, swill me!'' entreats Miranda Richardson's not-so-proper lady, throwing herself at the hero's twittish English counterpart (Grant). Okay, so it's not Tom Jones, but it'll do.