"Three French airships, Liebig trade card, c 1910. "
© Science Museum / Science & Society Picture Library
"'La Navigazione Aerea' (Aerial Navigation). One of a set of trade cards showing the French dirigibles 'La Republique', 'Ville de Paris' and 'Clement-Bayard'. Airships were used during World War I for both offensive military purposes and aerial observation. Its great military advantage was its ability to hover in a single location and remain airborne for long periods of time, but its size and relative lack of speed made it vulnerable to enemy airplane attack. The Liebig company produced sets of trade cards to promote their meat extract, a cheap and nutritious product invented in 1847 by chemist, Justus von Liebig. The meat extract was produced from 1865 at the Fray Bentos-Liebig processing plant set up in Uruguay. 1,863 sets of cards were produced continuously from 1872 until 1975 by which time the company had joined with Brooke Bond to become Brooke-Bond Oxo, owned by Unilever."