Miniature Sheets no. 2, 3 and 4: Visit of King of Romania (1937):

 

Miniature Sheet no. 5: Fifth National Philatelic Exhibition in Warsaw (1938):

 

Miniature Sheet no. 6: The Planned First Polish Flight of a Stratosphere Balloon from the Chocholowski Valley in the Tatra Mountains (1938) (1):

 

Miniature Sheet no. 7: 20th Anniversary of Independence (1938):

 

Miniature Sheet no. 8: Polish Legion 25th Anniversary (1939):

 

 

 

 

(1) In 1937 a stratospheric balloon flight was proposed in Poland. The Polish balloon aviation flourished thanks to the balloon and parachute factory in Legionowo, which used to make very good balloons. Polish aviators did very well in international balloon competitions, for example they won several times the Gordon-Bennett Cup. The military aviators proposed a balloon flight to break the world record of manned balloon flight altitude. The record was held at that time by an American aviator captain Stevens, who in 1935 flew to the altitude of 22 km.
The military organizers of the flight were told that their flight might be possible if they had a serious scientific goal besides that of breaking the record of flight altitude. A Scientific Council of the flight was formed and decided that the scientific goal of the flight would be a measurement of altitude dependence of cosmic ray intensity.
The balloon was named "Star of Poland". The flight crew was captain Zbigniew Burzynski - an experienced balloon pilot, who won twice the Gordon-Bennett cup and set three international records - and Dr. Konstanty Jodko-Narkiewicz, a cosmic ray physicist, traveler, alpinist and aeronaut.
The launch was planed for September 1938 in Chocholowska Valley in Tatra mountains. An attraction of the event was the presence of the world record holder, captain Stevens. Due to meteorological reasons, the launch was delayed many times. Finally, on 14 October the apparatus was installed in the balloon gondola and filling of the balloon with hydrogen began. The pilots come and took over but as the balloon lifted off the hydrogen gas ignited and balloon burned down relatively quickly. Luckily, there were no casualties. Although another flight attempt was planned for next year, the outbreak of the World War II prevented the flight.
To publicize this undertaking and to collect funds for it, the Polish mail issued a post stamp featuring the balloon. A special post mark was used at Zakopane post office and at the Chocholowska Valley.