Performing infrequently, Source is an acting group of conspicuous integrity. Thursdays through Sundays at 8:30 it is an offering two of Eugene O'Neill's early sea plays,"Ile" and "The Long Voyage Home," at ASTA, 507 8th St. SE.

These short plays - once linked under the latter title in an impressive John Ford film of 1940 - were both rooted in true stories of O'Neill's sea-faring days. They have the rugged, granite quality he exhibited so early, and while they are possibly of greater interest for what they reveal of O'Neill's life, a greater truth is in them.

It is this truth which Source's production illuminates, with Camille David directing "Ile" and Bart Whitrman "The Long Voyage Home".

The story of a captain's wife who never will regain her sanity after an endless whaling voyage to the Artic. "Ile" relies on the performances of Whiteman as the captain and Rebecca Beors Street as his wife. The implacable determination of the man and the gentleness of his wife are beautifully depicted in performances which achieve and maintain a gravity of rhythm.

The custon of shanghailing men for ship's labor is the basis of "The Long Voyage Home", set in a Baltimore waterfront saloon. O'Neill's period color and ironies are emphasized in the story of cautious Otto, whose self-knowledge does not extend to self-control. Bruce Clarke plays Otto with deceptive simplicity, building the part precisely according to O'Neill's development. As intended, we concentrate on him only gradually.

Both plays look better than they often do these days thanks to the confidence the directors show in the author's deliberate pace, a respect often denied older plays.

It is unfortunate that the scenic plan for "Ile" does not constrict the action to suggest the ship's cabin, and once more it seems that vocal techniques of power and control are not what these intelligent performers require for their best-intended effects. Nonetheless, both plays are presented with probity. Some of the other leading players include Chuck Turner, Bim Oakley, David Wildberger, Tim Quinn and Michaeleen O'Neil.