1915 'On Active Service' cover to Scotland with a ZOMBA 20.9.15. datestamp. Sent by Private J.C. Rhymas, B Company, British South Africa Police while en-route to the Northern Rhodesia border region. The cove has been endorsed with the initials 'W. B. Major'. This was Major Walter Baxendale of the Southern Rhodesia Volunteers who was killed in action a month later. This cover is the earliest recorded use at Zomba of the “On Active Service” free postage mail. Fine and very scarce.