The Canal Zone Postal Service issued the 10-cent Gatun Locks-After commemorative (Scott 127) of the Twenty-fifth Anniversary Series on August 15, 1939. The series includes eight 'before' and eight 'after' scenes of important Panama Canal areas and facilities. In the June 1924 bird's eye shot used for the 10-cent stamp, the scene is almost identical to that used on the 8-cent 'Before' stamp.
All three levels of the locks are clearly seen, as does the lake also named "Gatun." The lake formed when the giant earthen dam, barely seen at right, blocked the waters of the Chagres River. The Gatun powerhouse, the large building at left, stands near the site of the wooden construction- era building that appeared on the 8-cent stamp. The new town of Gatun appears at the far left, and ships can be seen approaching the locks from the lake and also in one of the chambers.
As planned, the 10-cent stamp covered airmail to some of the nearby Central American and Caribbean lands. Otherwise, patrons combined it with other stamps to satisfy postage on letters and packages.
Sales of the 10-cent stamp were double those of the 'Before' stamp with the same scene, leaving only about 126,000 to be withdrawn from sale on February 28, 1941, and burned on April 12 of that same year.
Collectors found the entire Twenty-fifth Anniversary Series extremely appealing when issued. In unused condition, the stamps are all readily available. However, other than on the literally dozens of different cacheted first day covers, the 10-cent on cover rarely appears. A fair number of covers bearing the 10-cent and other, higher value stamps of this series are found on letters containing stamp orders from the Canal Zone Philatelic Agency because the agency was apparently attempting to use the stamps when possible.