Gas production from hard coal, 1950ABOUT Rare historical wall charts on energy production, with detailed texts and explanations, made for school visual instruction in the 1950s. Printed after signed original illustrations of the commercial artists K. Kluger and W. Hauch. It got printed by the famous Hofmandruck in Vienna. Despite their age, the condition of the prints is as good as new, the drawings and illustrations are highly professional, the colors are beautiful and well preserved!