The Canal Zone Postal Service issued the 25-cent Gatun Spillway-Before (Scott 134) commemorative stamp on August 15, 1939, as one of the high values in the sixteen-stamp Twenty-fifth Anniversary Series. The series includes eight 'before' and eight 'after" scenes of important Panama Canal facilities.
This stamp features an image of the giant concrete spillway and gates as they appeared on February 13, 1913, when the impounded waters of the Chagres River began filling one of the world's largest artificial lakes. The dam itself at Gatun still stands almost unchanged from the day completed. It rises from over a half mile wide at its base to only a hundred feet at its crest and 105 feet above sea level. This scene sweeps over the new river channel towards the spillway from the downstream or northern side. In the far distance, a glimpse of the slowly filling Gatun Lake can be seen.
Like many of the stamps in this series, the 25-cent stamp had no readily identifiable use. Patrons used it as a 'make-up' stamp on packages and special usages such as registered airmail letters.
The Bureau of Printing and Engraving produced 105,000 of this stamp, the fewest of any stamp in the series. Only 34,283 sold, leaving almost 71,000 remaining after being withdrawn from sale on February 28, 1941. Of all the stamps in this series, only the 11-cent is scarcer, with barely over 34,000 having sold.
All of the stamps in this long series sold well on the first day of issue. Collectors purchased large quantities, and many appeared on cacheted first day covers. Like the others, covers postmarked at any of the smaller towns and military bases are scarce. In terms of non-philatelic usages, collectors consider it the scarcest. For example, the 11-cent, even rarer in terms of sale, occasionally appears on a first class airmail letter that cost fifteen cents.
The relatively high value of the 25-cent stamp precluded its use for anything but a special service usage or package. Collectors soaked most of these off; others just simply threw them away. A few appear on envelopes from the Canal Zone Philatelic Agency, but any other usage is rare.