Temps de résolution pour ce puzzlePartagez vos temps de résolution avec vos amis
When naturally occuring graphite was discovered, chemistry was in its infancy and the substance was thought to be a form of lead. Consequently, it was called plumbago (Latin for "lead ore") . The black core of pencils is still sometimes referred to as "lead," even though it never contained the element lead.
Partager ce casse-tête
Mer Reflection Fall LakeMar Boat on BeachLun Alluaudia ProceraDim Macaroon ThreeSam Trees by LakeVen Pachypodium LamereiJeu Candy QuartersAutres puzzles précédents