Since the Brattle Theatre Company has shown in "The Country Girl" that Restoration comedy can be sparkling and enjoyable in modern hands, there is good reason to be disappointed in the current production of "The Roaring Girl." The major disappointment is the play itself. It is a farce by Thomas Dekker and Thomas Middleton, about an old man, his wayward son, and a town character known as Mad Moll, the roaring girl. There are some moments of delightful comedy during the evening, but most of the time the actions seem mere posturing and the words mere wind.

It is no coincidence, either, that Nancy Walker seems to be onstage when most of the delightful putting much gusto into her acting as the roaring girl, she still manages to extract a good deal of humor from her material. It is not Restoration wit that gets the laughs when she is on; it is Nancy Walker, pure and simple. She wipes her nose with her sleeve and makes love to a cello with a savage determination that is generally both frightening and funny.

The trouble is that when Miss Walker says, with a Brooklyn intonation, "I'm much beholdin' t'ya," she is being funny by acting in direct opposition to the spirit of the play, instead of remaining true to that spirit. The rest of the cast stay pretty well within the confines of the script. Their acting is spirited, and a credit to themselves and to director Peter Temple, who comes as close to making the play live as possible. Especially engaging are Jerry Kilty as Trap Door, the scoundrel, and Robert Fletcher as Laxton, the lecher. Many of the minor characters are also amusing caricatures of London town-types; one of these is Jack Dapper, the fop, played by Nick Benton (who turns up again in a red wig).

Randall Thompson has selected some charming music, which, played on a piano that has been emasculated in some manner to make it sound like a harpsichord, provides a background for several brief interludes. Robert O'Hearn's sets, like the costumes by Chris Mahan and Robert Fletcher, are good but not up to the usual Brattle standard.

In spite of the brave attempt of director Temple and the cast, "The Roaring Girl" is often a tedious bit of theatrical fare. It is too strained, too contrived to be truly entertaining today. Long speeches come and go without conveying much meaning; a good deal of the famed Restoration bawdiness seems not so much bawdy as dull; and all in all, "The Roaring Girl" seems like a poor choice for the Brattle Theatre.