Subject
- Coal-tar colors5
- Farbenfabriken vorm. Friedrich Bayer & Co.5
- Mineral industries5
- Paint industry and trade5
- Scientists--Biography5
- Textile fabrics5
- Textile industry5
- Water--Purification5
- World War (1914-1918)5
- Agricultural chemicals4
- Baking powder4
- Chemistry--Experiments4
- Chlorination4
- DDT (Insecticide)4
- Dyes and dyeing--Chemistry4
- Education, Secondary4
- Electricity4
- Electrochemistry4
- Food adulteration and inspection4
- Food--Analysis4