Stamps of PANAMA
1901: Double rate cover from Panama October 1901 to London, England franked by two 1892 10c stamps (Scott 18) and 1892 Colombian Late Fee stamp (Scott I2). London receiving mark 1901 on reverse. R-4
For any mail introduced to the post office after closing will pay a rate of 2½ for every 15 grams or 15 minutes if the customer wanted it to leave that day otherwise it will be stamped with T (TARDE) late and it would leave the following day. This late fee was introduced by the Colombian postal authorite since March 1st, 1887.
The 2 ½ c Retardo stamp
*Resolution number 851 of 17 November 1896