1874, Justice 40 centavos lilac, 2 copies, tied by mute cancel to 2nd rate letter sheet with adjacent "ESTAFETA DE CAMBIO MADRID 1 JUL 75" to Lagnau, Switzerland. Originally the letter had been franked just with one stamp, the post detected second weight step, marked the letter "2" and applied the tax handstamp "T", which was cancelled after the sender applied second stamp for correct postage. Only reported FIRST DAY USE of the GPU “T”. A world class rarity.
