Franjo Hanaman (1878-1941), chemist and metallurgist, distinguished professor of the University of Zagreb, invented together with Aleksandar Just the first economical electric bulb with wolfram filament. During 1910, when Hanaman sojourned in the USA, his patent rights have been bought by the General Electric Co. During his visit, he met Nikola Tesla.

William David Coolidge, american physicist and since 1932 director of the scientific laboratory of General Electric Co, wrote on the occasion of Hanaman’s 50th birthday and the then 25th anniversary of his first patent the following in his letter sent to Professor Vladimir Njegovan (see [M. Kastelan-Macan, p. 53]):

Allow me, however, to take this opportunity to express my keen appreciation of the pioneer work of Professor Hanaman in the tungsten lamp field. To him and to Dr. Just belongs the honor of being the path finders who led the world to a wonderful new light.

Let me also pay my tribute to Professor Hanaman’s sterling character and lovable nature. I feel fortunate indeed in being able to count him as one of my very good friends.

For more detailed information, see Marija Kastelan-Macan: Franjo Hanaman, FKIT, Zagreb 2017.

Billions of electric bulbs worldwide, with wolfram filament, have been produced during the past hundred hears (from the beginning of 20th to the beginning of 21st centuries), based on the patents of Hanaman and Just.