As a result of the Taft Agreement of December 3, 1904, the Canal Zone Postal Service began issuing the Third Series on Monday, December 12, 1904. The stamps were issued for the same postal purposes as the stamps of the Second Series.
The Third Series is very interesting and presents the Canal Zone specialist with the best opportunity for plating, in this case a particularly fascinating study and a stiff collecting challenge because of the almost endless combinations of Canal Zone overprints, Panama overprints, Panama surcharges, Canal Zone errors, Panama errors, Canal Zone varieties, Panama varieties, and assorted oddities.
The Third Series includes the 1-cent green (Scott No. 9), the 2-cent rose (Scott Nos. 10 and 11), the 5-cent blue (Scott No. 12), the 8-cent on 50-cent bistre brown (Scott Nos. 14, 15, 18, 19, and 20), and the10-cent yellow (Scott No. 13). Although these ten stamps include three different basic Panama issues, they are considered to be only one Canal Zone issue because each was overprinted with the same Canal Zone overprint plate in at least one and often more of its six stages, and usually several of these stamps were overprinted with the same stage(s).
The majority of the Third Series was first issued December 12, 1904, including the first printings of Scott Nos. 9, 10, 12, 14, and the only printing of Scott Nr. 15. The rest of the stamps—Scott Nos. 11, 18, 19 and 20—were issued in late 1905.
When this series went on sale, the director of posts wrote a memorandum to all postmasters, saying, ". . . these stamps will be sold for their face value in gold; Colombian silver will be accepted for payment for postage at the rate of two for one." Thus, because U.S. currency was based on the gold standard, the denomination of each stamp corresponds to U.S. currency, dollars and cents (as is the case with all subsequent Canal Zone issues).
Various quantities of these stamps were delivered to the Canal Zone between December 10, 1904, and August 1906. They were at first overprinted under the authority of the Canal Zone Division of Map Making, and then in August 1905 the job was transferred to the Printing Bureau of the Engineering Department, also known as the 'Commission Printing Office'.
Collectors have recognized a total of six stages of overprinting.
Quantities of Third Series Stamps
Scott Number Description Quantity Issued
9 1-cent Green Map, 1st Rep. of Panama stamp series, Scott 179 319,800
10 2-cent Rose Map, 1st Rep. of Panama stamps series, Scott 180 367,500
11 2-cent rose, overprint of Panama Scott No. 77 150,000
12 5-cent blue, overprint of Panama Scott No. 78 400,000
13 10-cent yellow, overprint of Panama Scott No. 79 64,900
14 8-cent brown, overprint of 50-cent Panama Scott 81 27,800 estimate
15 8-cent brown, overprint of 50-cent Panama Scott 81 500
18 8-cent brown, overprint of 50-cent Panama Scott 81 17,500 estimate
19 8-cent brown, overprint of 50-cent Panama Scott 81 19,000 estimate
20 8-cent brown, overprint of 50-cent Panama Scott 81 19,600