China. (Indo-Chinese Post Offices in Canton - India). 1904. Registered envelope addressed to Bombay bearing Canton SG 23, 20c red/ green (2) and SG 23, 30c cinnamon (pair) tied by Canton - Chine double ring '3rd Juin 04' with boxed hand-struck 'R', endorsed 'Per Steamer "Simla" with oval 'Sea Post Office' (registered) on face, routed via Hong Kong with Registered/ Hong Kong transit 'Ju 4' and Bombay arrival '22nd June' on reverse..
Scarce Indo-Chinese Post Office stamps on cover sent through the Indian Sea Post Office with oval endorsed '1478' in blue crayon in center.