Poenaru’s fountain pen
In 1826 he went to France and attended the École Polytechnique in Paris, where he studied geodesy and surveying. He was so busy taking notes and copying courses, that he invented a fountain pen that used a swan’s quill as an ink reservoir. On 25 May 1827, the Manufacture Department of the French Ministry of the Interior registered Poenaru’s invention with the code number 3208 and the description “plume portable sans fin, qui s’alimente elle-meme avec de l’ancre” (“never-ending portable pen, which recharges itself with ink”).
In 2010 Poșta Română issued a 5 lei stamp depicting Poenaru next to his fountain pen project.
The Petrache Poenaru metro station in Bucharest is named in his honor.