LIBERIA (1980) Hydro-electric plant. Imperforate proof mounted on Format International Security Printers card. Scott No 756, Yvert No 879.
AVAILABLE AT $60
AUSTRIA (2019) Victor Kaplan. Turbine. Black print.
AVAILABLE AT $15
GERMANY (1957) Spark gap transmitter*. Photo essay (See Note) of unaccepted design for 100th anniversary of birth of Heinrich Hertz. Scott No 762, Yvert No 131.
AVAILABLE AT $60
GERMANY (1957) Electromagnetic waves. Candle. Photo essay (See Note) of unaccepted design for 100th anniversary of birth of Heinrich Hertz. Scott No 762, Yvert No 131.
AVAILABLE AT $60
GERMANY (1957) Electromagnetic lines of force. Candle. Photo essay (See Note) of unaccepted design for 100th anniversary of birth of Heinrich Hertz. Scott No 762, Yvert No 131.
AVAILABLE AT $60
GERMANY (1957) Electromagnetic lines of force. Stylised people. Photo essay (See Note) of unaccepted design for 100th anniversary of birth of Heinrich Hertz. Scott No 762, Yvert No 131.
AVAILABLE AT $60
GERMANY (1957) Heinrich Hertz. Photo essay (See Note) of unaccepted design for 100th anniversary of birth of Heinrich Hertz. Scott No 762, Yvert No 131.
AVAILABLE AT $60
GERMANY (1957) Magnetic lines of force. Waves. Photo essay (See Note) of unaccepted design for 100th anniversary of birth of Heinrich Hertz. Scott No 762, Yvert No 131.
AVAILABLE AT $60
GERMANY (1966) High voltage power transmission tower. Photo essay (See Note) of unaccepted design for 75th anniversary of discovery of 3-phase transmission by Dolivo & Dobrowolsky. Scott No 965, Yvert No 378.
AVAILABLE AT $60
GERMANY (1966) Transmission pole with insulators. Photo essay (See Note) of unaccepted design for 75th anniversary of discovery of 3-phase transmission by Dolivo & Dobrowolsky. Scott No 965, Yvert No 378.
AVAILABLE AT $60