nHaves, Chorus In 1st RehearsalFree Tickets Available For Concert Starring Negro TenorRoland Hayes, American Negro tenor, and a chorus of 200 Negro aviation engineers held their first joint rehearsal vestc day in 1 ondon for tfie concert they will give with the London Symphony Ore he ora in Royal Albert Hall next Tuesday and Wednesday evenings.The soldiers sang “Go Down, Moses and “Jo-huu F it the Battle of Jericho” with Have-, who came from the United States to take part in the concert. Thev will rehearse in Royal Albert Hall for the lirst time this afternoon.Erec tickets for the Wednesday per-formance will be available lor enlisted men and officers of Central Base Section beginning tomorrow* morning at the Special Service office in London. American soldiers showing pass or furlough papers may obtain free tickets at the American Red Cross Rainbow Corner at 11 AM Wednesday. Ticket-holders are asked to be in their seats in the hall at 5.45 PM Wednesday.All tickets for the Tuesday performance have been sold. The concert is sponsored by the London Daily Express, in conjunction with Headquarters, IIOLSA.