What Did Slavoljub Eduard Penkala Invent?

Slavoljub Eduard Penkala was a Croatian engineer and inventor of the first mechanical pencil or then called 'automatic pencil' in 1906 and the first solid-ink fountain pen in 1907. He also designed the first Croatian two-seat aeroplane in 1909. Together with an entrepreneur named Edmund Moster, he started a factory of pens and pencils called 'Penkala-Moster' and it still exists today called 'TOZ-Penkala'.