Burma to Boston 1855 via Southampton

This 0-1/2 oz. tissue paper letter was datelined in Henthada, Burma on Feb. 17, 1855 and sent to Boston.  A pair of the first Issue of India paid the rate to Calcutta, but it was unpaid thereafter.  From there it took P&O steamers to Southampton and a Cunard steamer from Liverpool to Boston.  The 1 shilling mark at left was the rate between a British Colony and the U.K.  At Boston, the addressee paid there full 45c rate between the U.S. and British India (Burma was part of India at that time). Because it was carried on a British Packet to Boston, there was a 40c credit to the U.K.