The letter was send from the Army on Active Service at Balcans(field post sub-office #4 - 26/01/1879) via St.-Petersburg 31/01/1879 to Helsingfors
(Finland). Why the handstamp "BEZ.PLAT.(NO)" (free of charge)? As is known, this handstamp was used only for letters delivered free of special charge
to some addressees within St.-Petersburg