Isle Of Man. (Prisoner Of War Mail). 1915. Registered 'Prisoner of War' envelope addressed to Devon bearing SG 368, 2d orange tied by Peel date stamp '5th Mar 15' with 'R/Peel' registration label and oval 'Aliens Detention Camp/Knockaloe, I.O.M.' in violet on face routed via Liverpool with Sidmouth arrival on reverse. Herman Heiser was interned early in the war first in the short lived Stratford Camp and then Deepcut and Frimley Camps before being transferred to Knockaloe Camp. Scarce item of registered mail paying the 2d registered rate after the rate change.