The supply of Colombian registration stamps was exhasted in March 1900. Resupply was impossible due to the civil war. While a provisional registration stamp, Scott Panama F3, was been printed, a stock of the current 10 centavos stamps was handstamped with a large "R", these were used for 3 days on the 14, 15 and 16 of March of 1900. 

Schaye reported in 1961 that a few hundred of these stamps were prepared and used. He illustrated a local cover addressed to Angelo Lupi with registration number 2215.  He also stated he had examined pieces or loose stamps whith numbers 2096-2097, 2121, 2123 and 2240 and that number 2245 was known on a scott Panama F3. The Helme collection contained five covers with provisional stamps with numbers 2021, 2041, 2068, 2212, 2236 and a piece with 2128.  His notes stated that he knew the existence of seven covers and seven loose stamps. There have been 5 new discovered with a total of twelve. The other two covers were those from James Cross collection the second is a Wo Kee cover to San Francisco reduced at right, but showing the registration stamp with number 2028 which is the only known cover with this stamp from foreign mail. There is also 2099 on piece.addressed to Sr Don manuel Lynns, Panama, just like 2068, reconstructed.

Helme covers: 2021, 2041, 2068, 2212 and 2236
James Cross:  2215, 2028
Shown here:.   2229
Others:             2228, 2234, 2235, 2036
On piece:         2099 see it reconstructed
Stamps of PANAMA
2nd MAP ISSUE 1892-95
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The 1900 Provisional "R" stamp

Used on March 14, 15 and 16, 1900
This stamp registration number is a makeshift. Any number other than the ones or in between those mentioned are considered  makeshift.
Provisional 'R' handstamp, 1892: 10 c. orange, used with 10 c. orange with Provisional 'R' registration stamp with blue '2028' handstamp, on reduced cover, from Panama to San Francisco, dated 14 March 1900, tied by Panama datestamp in black, on reverse New York registered oval in black dated 29 March 1900 and partial San Francisco arrival in purple (3 April)
1900 Mar 16 provisional local registered arrived March 17, 1900 with registration number 2229.